Horsepower

[EHog]

1st place auto-x at FSAE WEST had ~96HP and the car weighed ~425 with wings.

2nd place auto-x at FSAE WEST had ~48HP and the car weighed ~413 with wings.

How much relavance do the facts above have to the question I am asking below? Probably very little but I just thought I would inform...



I have been reading the FS Electric vs. FSC thread and I even noticed that one team said they limited power output to 70% in auto-x...


My question is, how much power do teams have? How much do you believe this helps times?

Also, a fundamental question that I simply do not know the answer to... Why was a restrictor of 19/20mm implemented? Was it a safety precaution or more of an engineering design challenge?

-Evan

[EHog]

1st place auto-x at FSAE WEST had ~96HP and the car weighed ~425 with wings.

2nd place auto-x at FSAE WEST had ~48HP and the car weighed ~413 with wings.

How much relavance do the facts above have to the question I am asking below? Probably very little but I just thought I would inform...



I have been reading the FS Electric vs. FSC thread and I even noticed that one team said they limited power output to 70% in auto-x...


My question is, how much power do teams have? How much do you believe this helps times?

Also, a fundamental question that I simply do not know the answer to... Why was a restrictor of 19/20mm implemented? Was it a safety precaution or more of an engineering design challenge?

-Evan

[thewoundedsoldier]

As I understand it, the restrictor is more to level the playing field. Without it, 450s could not compete with 600s. It brings engines into the same arena while giving teams much more design freedom than dictating a common engine like Baja does. Any old-timers have better insight into the rule?

The point about power is definitely appropriate. At Formula Hybrid this year, the second place overall team shut down their entire electrical drive system during endurance and only ran their 250cc engine because they knew they would be traction limited (the track was damp, and by damp i mean very lightly damp). To get traction limited with a 250cc on a nearly-dry track really says something.

[exFSAE]

Could someone remind me what max power can be generated by a choked flow 20mm restriction burning gasoline?

Asking teams how much power their make is an exercise in futility and BS. Dynos will tell you all sorts of things.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:
Without it, 450s could not compete with 600s. </div></BLOCKQUOTE>

Thats really my question though... Does it actually level the playing field? In a straight line? Maybe a bit... On a course though? We spend a considerable amount of time in corners...

Tell me what you think.



<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by exFSAE:
Asking teams how much power their make is an exercise in futility and BS. </div></BLOCKQUOTE>

exFSAE: Knowing how much HP car X has vs. car Y is clearly not going to make our team's car go any faster... It was meant more to be like "Fun Facts"

There are however, three more questions AFTER the futile question.

Suggesting im ignorant does not really help out anyone...


-Evan

[RenM]

a good power to weight ratio will always help you, as long as you dont sacrifice in other areas.

the singles can make up their lack of power on slow tracks by being able to drive a better line through tight corners. So it really depends on the track.

[thewoundedsoldier]

It might not level the playing field PERFECTLY equal, but I think it is as close as can get. It even in discrete ways forces vehicle dimensions onto the teams (wheelbase, track widths, CG height). I think that although it might not make a straight line when it comes to an autocross course, it does come pretty close after you consider ALL point-scoring opportunities.

I think that what exFSAE means is that team-provided HP numbers are generally garbage and useless as a point of comparison. How do we know that 1st place autox at west had 96HP and 2nd place had 48HP?

[BeaverGuy]

The displacement limit, restrictor, and throttle/turbo position wrt the restrictor are safety featurse. The restrictor with the throttle before and turbo after the restrictor limits airflow to ~72g/s and maximum power to around 110hp if you have a perfect setup. If there was no restrictor then FSAE would probably ban forced induction to keep power levels sane. I think the fact that smaller displacement engines can keep up with the larger engines is a bit of an after the fact effect. I can't imagine the rules committe envisioned teams using 450cc singles to try and compete with 600cc 4cylinders when they developed the restrictor rules 20 or so years ago. From the first competition I attended in 2004 I can only recall maybe 2 single cylinder teams however they made a big impression and other teams started to look at the singles more seriously after that time.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:
How do we know that 1st place autox at west had 96HP and 2nd place had 48HP? </div></BLOCKQUOTE>

I talked a lot with the engine guy from the 1st place autox team and our team was the 2nd place autox... Then again, from an outside standpoint, we could both be full of crap. http://fsae.com/groupee_common/emoticons/icon_cool.gif

Like I said... Fun "facts"

-Evan

[RobbyObby]

woundedsoldier is right. We ran engine dyno runs before West last year and were getting numbers in the 70s. But on the dyno at competition we only got like 56 or something. Unless you run all the teams on the same dyno there's no way to compare numbers.

Also what you have to consider, as RenM mentioned is the power-to-weight ratio. A 450 might not produce as much power as a 600 but it weighs considerably less.

[VFR750R]

I think the primary purpose of the restrictor was safety. But once implemented then they could open the rules to forced induction and keep power levels similar. I think when the original rules were written, no water cooled singles existed. The only real choice in the late 80's and all of the 90's were 600 cc 4 cylinder engines.

[thewoundedsoldier]

Missouri is not in the event guide so I don't know what path they took, but your car looks very small. 48/44 track is small.

We all know the weight savings involved, but more important is the dimension difference between large, powerful cars and small, agile ones. I'm sure you and OSU had an easier time in the slaloms, and Missouri had better acceleration off the corners.

I'll bite and provide numbers on our car. The 2010 SJSU Formula Hybrid car had two motors rated at 35kW each. Just thinking of that power number makes me laugh. We probably only realized about 25 HP each.

[TMichaels]

Just to fill the discussion with some data, which is at least a bit feasible: In 2008 we had some cars on the same dyno at FSG. The data can be found here w w w .formulastudent.de/fileadmin/user_upload/all/2008/Results/FSG08_Dyno_Results.xls

The results of the dynamic events from that year can be found here:
w w w .formulastudent.de/events/event-2008/results/

Maybe it helps.

Regards,

Tobias

[bob.paasch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
1st place auto-x at FSAE WEST had ~96HP and the car weighed ~425 with wings.

2nd place auto-x at FSAE WEST had ~48HP and the car weighed ~413 with wings.
</div></BLOCKQUOTE>

... and the 3rd place Autocross at FSAE West had ~45 HP and the car weighed 325 with an undertray. http://fsae.com/groupee_common/emoticons/icon_smile.gif

The same car without the undertray was 2nd in autocross at FSAE Michigan, 1st at FSUK, 2nd at FSG, and 4th at FSA.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
My question is, how much power do teams have?
</div></BLOCKQUOTE>

GFR, not much... http://fsae.com/groupee_common/emoticons/icon_smile.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
How much do you believe this helps times?
</div></BLOCKQUOTE>

As Steve and Pat are fond of saying, this is a handling competition, not a power competition.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Also, a fundamental question that I simply do not know the answer to... Why was a restrictor of 19/20mm implemented? Was it a safety precaution or more of an engineering design challenge?
</div></BLOCKQUOTE>

The restrictor was implemented primarily a safety precaution, but it certainly has worked out to be a nice design challenge.

My question for you, if you're only getting 48 HP out of that Ape, why bother? The 450 singles are cheaper, simpler, and lighter.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rp:
My question for you, if you're only getting 48 HP out of that Ape, why bother? The 450 singles are cheaper, simpler, and lighter. </div></BLOCKQUOTE>

To be honest, our peak HP could be anywhere between 45-60. We would have a legitimate number but we have a chain reduction on our dyno because the engine has so much torque at low RPM that the dyno couldn't pull it down.
It was going to go on the dyno at WEST after endurance but... well... lets just say the large cloud of smoke ruined that for us.



Bob,

We ran an F4i for many many years, and in 2009 we decided to switch to the Ape. The two primary reasons for switching was because
A) the ape is ~60lbs lighter
B) we wanted the nearly flat torque curve so that gear selection was much less critical

On a course in which you may need 1st-4th gear on the F4i, suddenly you only need 2nd and 3rd...
I know there are many more reasons but myself not being the engine guy, I won't even try to guess.


Out of curiosity, how much does your single cylinder with tranny weigh Bob? And what does the torque curve look like for such an engine?



NOTE: I am by no means the engine guy and if something in the above text is completely invalid, I apologize.

[thewoundedsoldier]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
B) we wanted the nearly flat torque curve so that gear selection was much less critical </div></BLOCKQUOTE>

+1

I think that's a subtle answer to the question this thread poses. Between 450cc singles and 600cc 4-cylinders, one type of engine has a flat torque curve and the other has a sharp torque curve. It's going to be hard to stay in the power band with the latter.

The GFR powerplant is a CRF450. I believe it peaks at like 35 ft*lbs @ 7k RPM, with a decently flat curve between 5k and 8k. I would be very happy to see Dr. Paasch provide tested numbers (i.e. after restriction!) http://fsae.com/groupee_common/emoticons/icon_biggrin.gif although this might be asking a bit much.

[Demon Of Speed]

On the note of singles having a flat power curve; it makes it much easier for non-professional drivers to drive the car fast(er).

I would bet there is as much time difference in autox due to different drivers as there is to differences in HP. Our fast guy in endurance was 2 sec. faster a lap than the other guy, I can't imagine going from 40-80 HP would make as large of a difference.

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[thewoundedsoldier]

I think the singles will generally have a less flat power curve.

Motorcycle engines are made to be driven easily i.e. flat curves--dirtbike engines focus on that peak torque at the cost of the wide band. While a dirtbike might plateau for a range of 2000-3000 RPM, a motorcycle engine (like the Aprilla SXV) has a range of closer to 5000 RPM.

This is the advantage of a *heavier* motorcycle engine. While durability is a perk, the ability of an inexperienced driver to stay in the band is clutch.

I'm also very much NOT an engine guy, so hopefully other, more experienced members can provide some insight.

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Demon Of Speed:
On the note of singles having a flat power curve; it makes it much easier for non-professional drivers to drive the car fast(er).
</div></BLOCKQUOTE>

i can not confirm that. I am a non professional driver and i had the opportunity to drive a top 4 cylinder car and a top 1 cylinder car. The 1 cylinder car was much harder to control when accelerating out of the corner. The 4 cylinder delivers the power much smoother and the throttle response was a lot better making it very easy to accelerate right on the edge.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
i can not confirm that. I am a non professional driver and i had the opportunity to drive a top 4 cylinder car and a top 1 cylinder car. The 1 cylinder car was much harder to control when accelerating out of the corner. The 4 cylinder delivers the power much smoother and the throttle response was a lot better making it very easy to accelerate right on the edge. </div></BLOCKQUOTE>

I dont buy this. Im not saying you are wrong in your observations, but... the suspension/drivetrain/chassis/ergo/everything of a seperate car could be enough to do this. The engine could have played a huge role in your experience or none... we cannot really say.

[Bemo]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
i can not confirm that. I am a non professional driver and i had the opportunity to drive a top 4 cylinder car and a top 1 cylinder car. The 1 cylinder car was much harder to control when accelerating out of the corner. The 4 cylinder delivers the power much smoother and the throttle response was a lot better making it very easy to accelerate right on the edge. </div></BLOCKQUOTE>

I dont buy this. Im not saying you are wrong in your observations, but... the suspension/drivetrain/chassis/ergo/everything of a seperate car could be enough to do this. The engine could have played a huge role in your experience or none... we cannot really say. </div></BLOCKQUOTE>

I don't see how you could compare the driveability of both concepts better than driving good versions of both.
I only drove cars from my team which all were 4-cyl cars. I can only say that I can hardly imagine that there should be any engine out there which is more driveable. Our 08 car had a very flat torque plateau from 5000 till 11000 rpms. And the response to the throttle is unbelievable.

I believe that in generel 4-cyl engines run smoother compared to singles and are therefor easier to drive. But that has nothing to do with the discussion about power.

I have to admit that I came to the opinion that you don't need a lot of power to perform well in dynamics (as Delft and GFR have sufficiently proven). But if you ask me - 4-cylinder cars look and sound better therefor they are more worth to be built http://fsae.com/groupee_common/emoticons/icon_wink.gif!

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">But if you ask me - 4-cylinder cars look and sound better therefor they are more worth to be built Wink! </div></BLOCKQUOTE>
+1

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:
But if you ask me - 4-cylinder cars look and sound better therefor they are more worth to be built http://fsae.com/groupee_common/emoticons/icon_wink.gif! </div></BLOCKQUOTE>

Our new cars have an ape in them... kind of a very angry sounding engine.

Sometimes (quite often) i just start up the older F4i cars just to listen to them... What a glorious sound http://fsae.com/groupee_common/emoticons/icon_cool.gif



Then again, when we kick some more 4-cyl butt with our ape... suddenly im fine with the angry engine again!

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
i can not confirm that. I am a non professional driver and i had the opportunity to drive a top 4 cylinder car and a top 1 cylinder car. The 1 cylinder car was much harder to control when accelerating out of the corner. The 4 cylinder delivers the power much smoother and the throttle response was a lot better making it very easy to accelerate right on the edge. </div></BLOCKQUOTE>

I dont buy this. Im not saying you are wrong in your observations, but... the suspension/drivetrain/chassis/ergo/everything of a seperate car could be enough to do this. The engine could have played a huge role in your experience or none... we cannot really say. </div></BLOCKQUOTE>
though not professional i am experienced enough to feel the difference between an agressive suspension setup and an engine that is running not as smooth as a 4 cylinder does. Throttle response is very easy to feel and has nothing to do with the rest of the car.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">But if you ask me - 4-cylinder cars look and sound better therefor they are more worth to be built Wink! </div></BLOCKQUOTE>
+1 </div></BLOCKQUOTE>

Definitely prefer the sound of a 4-cyl above the lawnmower sound of a single.

With respect to sound electric cars are a bit boring. How about adding a rule: "the car has to be equipped with a speaker system that can produce 110 dbA and an audible (loud) engine sound must be heard at the times the car is active"

Come to think of it, it's safer too http://fsae.com/groupee_common/emoticons/icon_wink.gif

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">With respect to sound electric cars are a bit boring. How about adding a rule: "the car has to be equipped with a speaker system that can produce 110 dbA and an audible (loud) engine sound must be heard at the times the car is active" </div></BLOCKQUOTE>

I thought about it, but it would ruin the night endurance http://fsae.com/groupee_common/emoticons/icon_frown.gif

Regards,

Tobi

[JVC]

Think of the upside though, an "engine sound selector" switch on your dash... today I think I will go for the V12... How awesome would that be http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

But to get back to the thread, I believe that at this year's FSG we have seen a very good argument for the single cylinder car, by Delft taking home the first prize, winning both overall dynamics and fuel efficiency. Admittedly fuel efficiency does not sound very cool, but it represents a fair amount of the overall points you can win.

Cheers,
Julien

[Zac]

The Fisker Karma, or at least the prototype I've seen on youtube, actually does have an external speaker to make a synthetic engine sound. It looks like their engineers opted for "jet engine."

It is a shame the rest of the car is an understeering pig.

[bob.paasch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rp:
My question for you, if you're only getting 48 HP out of that Ape, why bother? The 450 singles are cheaper, simpler, and lighter. </div></BLOCKQUOTE>

To be honest, our peak HP could be anywhere between 45-60. We would have a legitimate number but we have a chain reduction on our dyno because the engine has so much torque at low RPM that the dyno couldn't pull it down.
It was going to go on the dyno at WEST after endurance but... well... lets just say the large cloud of smoke ruined that for us.



Bob,

We ran an F4i for many many years, and in 2009 we decided to switch to the Ape. The two primary reasons for switching was because
A) the ape is ~60lbs lighter
B) we wanted the nearly flat torque curve so that gear selection was much less critical

On a course in which you may need 1st-4th gear on the F4i, suddenly you only need 2nd and 3rd...
I know there are many more reasons but myself not being the engine guy, I won't even try to guess.

Out of curiosity, how much does your single cylinder with tranny weigh Bob? And what does the torque curve look like for such an engine?

NOTE: I am by no means the engine guy and if something in the above text is completely invalid, I apologize. </div></BLOCKQUOTE>

If you're getting 60 HP out of the Ape, it may be worth the associated hassles. But if you're only getting 45 HP, well that's easy to get with a 450 single.

The CRF450X is around 30 kg. But don't forget the intake, exhaust and engine peripherals probably end up lighter as well. The Honda is dead easy and cheap to rebuild, and there's a TON of aftermarket support for these motors.

Our torque is dead flat from 6-10k rpm, however RenM's comment about drivability has some merit. To get a single to work with the restrictor, you need a pretty good sized plenum, which plays havoc with your throttle response. ETS runs a flap in their intake to give them two plenum volumes, Delft runs two fuel injectors.

I think the Ape was a very good answer two years ago when fuel efficiency was 50 points, but with fuel now at 100 points I see few areas of advantage over a 450 single. I have a lot of admiration, however, for the teams that have stuck with it and made the Aprilia work in an FSAE car. It was a real pleasure to see (and hear) Oklahoma ripping the enduro course at FSG.

In the end, winning competitions is about the points. Having 95 HP will gain you some points in some areas, but will also lose you some points in others. The original question was about how much power you need, well 3 of the 5 competitions this year (including the two most competitive) were won by cars with less than 50 HP.

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The original question was about how much power you need, well 3 of the 5 competitions this year (including the two most competitive) were won by cars with less than 50 HP. </div></BLOCKQUOTE>

I do not really see a statistical significance related to the engine concept as every official event except Japan in 2009 was won by a 4-cylinder car. Correct me, if I am wrong, but at least it is always the team winning the event and not the engine, the chassis, the tires, the electronics or whatever. I see so many threads discussing "Which xxx(insert random part of an FS car here) is best?"
Usually all of this discussions end up with: If it is done properly, nearly every concept is able to win an event.
The extra points for efficiency may favor the single cylinder cars a bit, but I don't think that we will see a real domination. If Delft would build a 4-cylinder car instead of a single, they would still be one of the top teams, because of their team and not because of their concept. The same counts for all other top teams in my opinion.

It would be really interesting to have a forced concept change every two years. For example every team has to change the number of cylinders every two years. Then we have a real design challenge!

Regards,

Tobias

[Mike Cook]

Tobias,

I'm sure you are aware that there was a rule change with regards to fuel economy in late 2008. The single cylinders proved that they can run just as fast as the 4 cylinders. Their fuel economy will always be better. With 100 points for fuel, there is really no reason to run a four cyclinder anymore. In 2011, they are going to cut back the points for acceleration to 50 as well, and this was one of the few places I think the 4 cylinders had an advantage.

[TMichaels]

Yes Mike, I am aware of the rule change after 2008. Did any comment from me lead you to a different assumption? That is why I wrote about the "extra" points. I meant the additional 50 points since 2009.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The extra points for efficiency may favor the single cylinder cars a bit, </div></BLOCKQUOTE>

There are several reasons to use a 4-cylinder:
1) Sound

2) Reliability, if one cylinder fails you still have three left http://fsae.com/groupee_common/emoticons/icon_cool.gif To be honest I know of several teams finishing endurance with 3 cylinders after one ignition coil / injector has failed. Reliability seems to be a weak part of the singles, maybe because of the vibrations?

3) Learning for real-life. No production car runs a single cylinder engine. Exhaust simulation and design for example should be much more complex for 4-cylinders. I'm not an engine guy, so please don't hurt me, if I am totally wrong.

4) Financial reasons. To my experience there are a lot of used 4-cylinders engines available, because the riders of these bikers are usually a bit reckles. The market for single cylinders is a lot smaller, since the enduro riders normally do not wreck their bikes or they fix them instead of selling them.

Regards,

Tobias

[Bobby Doyle]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Cook:
Tobias,

I'm sure you are aware that there was a rule change with regards to fuel economy in late 2008. The single cylinders proved that they can run just as fast as the 4 cylinders. Their fuel economy will always be better. With 100 points for fuel, there is really no reason to run a four cyclinder anymore. In 2011, they are going to cut back the points for acceleration to 50 as well, and this was one of the few places I think the 4 cylinders had an advantage. </div></BLOCKQUOTE>

Yep. http://fsae.com/groupee_common/emoticons/icon_frown.gif

I think a discussion of the upcoming points changes could be a new thread in itself, but I'll leave that to someone else...

[Mike Cook]

Sorry Tobias, I didn't mean to sound condescending. What I meant was, that the rule was put into place late in 2008 which means for the 2009 seasons teams really didn't have time to adapt which is probably why you still saw a lot of 4 cylinder teams winning. By 2010, a lot of teams had switched over and/or gained the necessary experience to become competitive with the singles.

With that said, you bring up some decent points of running a 4 cylinder, but here are some counter points -

Complexity - 4s have 4 of everything, which makes the wiring harness more complicated, header more complicated, intake more complicated, fuel system more complicated. You argue the 4's have better reliability, but I would think the singles are have a lot less things to go wrong (albeit when it does go wrong, your pretty much dead in the water - but in the endurance, if anything goes wrong (like lose a cylinder), you're probably not going to win).

Cost - Yes the 4s are cheap compared to lets say the ape, but singles are plentiful in the dirtbike/atv world, and like Mr. Paasch said, the aftermarket thrives and is probably more informed/educated then the streetbike crowd.

Availability - All the f4i's are getting old. The power bands of the new 4s are shifted up a lot which isn't going to work as well for a restrictor setup. Pretty much any used engine these days have a lot of miles on them and need a lot of work to even put in our car.

Sound - Yeah, you're right. 4s sound like mini indy cars. But then I heard UTA's turbo 250. Geez, talk about f1 sounding.


Anyways, I agree its about time for a post on the points distribution. I said it before and I 'll say it again. I don't mind the points layout THAT much, but what I do hate is the scaling of the points system. For instance, the difference between pulling 1.3g and 1.4g in the skid pad is incredible, but the points system does not reward it much more than going from 1.2g to 1.3g.

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Cook:
Tobias,

I'm sure you are aware that there was a rule change with regards to fuel economy in late 2008. The single cylinders proved that they can run just as fast as the 4 cylinders. Their fuel economy will always be better. With 100 points for fuel, there is really no reason to run a four cyclinder anymore. In 2011, they are going to cut back the points for acceleration to 50 as well, and this was one of the few places I think the 4 cylinders had an advantage. </div></BLOCKQUOTE>
In 2009 the Fuel rule was much harder then this year. And even though it was a very close battle with Delft, we won 3 competitions. At FSG 2009 we lost only 22 points to Delft in Fuel...
It got much harder for a 4 cylinder car with the rule changes and Delft and Oregon build very good cars but the singles are far from being dominant and being a must have.

regarding reliability:
The 4s are almost bullet proof. In contrast to a single you run them under the factory spec. You have to punish those engines really hard before they fail.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rp:

The CRF450X is around 30 kg. But don't forget the intake, exhaust and engine peripherals probably end up lighter as well. </div></BLOCKQUOTE>

Thats about 66lbs. From what I know, our ape is 72lbs dry (i could be wrong). You're right however, the peripherals will be somewhat lighter, but I wouldnt say a ton. So... Im going to take a shot in the dark and say your engine package is about 12-15lbs lighter than ours. Your car however, was 85-90lbs lighter than ours...

That would make it sound as though we might look at other areas of the car for weight loss first...

[Mikey Antonakakis]

Our F4i sounded good at Michigan this year, a few teams said we had the best-sounding car there... if only we would have double-checked that every cooling hose was actually a reinforced hose... http://fsae.com/groupee_common/emoticons/icon_frown.gif

[Dsenechal]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by rp:

The CRF450X is around 30 kg. But don't forget the intake, exhaust and engine peripherals probably end up lighter as well. </div></BLOCKQUOTE>

Thats about 66lbs. From what I know, our ape is 72lbs dry (i could be wrong). You're right however, the peripherals will be somewhat lighter, but I wouldnt say a ton. So... Im going to take a shot in the dark and say your engine package is about 12-15lbs lighter than ours. Your car however, was 85-90lbs lighter than ours...

That would make it sound as though we might look at other areas of the car for weight loss first... </div></BLOCKQUOTE>

Keep in in mind, you can build a much smaller frame in the rear end department, to accommodate the smaller engine. Plus a smaller wheelbase, if so desired, making for a lighter car overall. that along with 1/4 the weight of the headers, ligher intake, smaller gas tank as fuel economy is better, smaller radiator due to smaller engine with less power, etc... Alot of weight to shave on peripheral engine components switching to a single

We are switching to a single cylinder for the coming year, and have saved a considerable amount on the frame alone, close to 10 lbs from the 4cyl frame of last year. We are shooting for a 75 lb weight reduction wet on the overall weight.

[Demon Of Speed]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Cook:
Tobias,

I'm sure you are aware that there was a rule change with regards to fuel economy in late 2008. The single cylinders proved that they can run just as fast as the 4 cylinders. Their fuel economy will always be better. With 100 points for fuel, there is really no reason to run a four cyclinder anymore. In 2011, they are going to cut back the points for acceleration to 50 as well, and this was one of the few places I think the 4 cylinders had an advantage. </div></BLOCKQUOTE>

regarding reliability:
The 4s are almost bullet proof. In contrast to a single you run them under the factory spec. You have to punish those engines really hard before they fail. </div></BLOCKQUOTE>

The singles are easy to work on. The area we have the most reliability on is the starting system (for a single), which is amplified by trying to run E85. The problem is that well they have a starter they also have a kick start so the manufactures don't build the electric starters (and subsystems related) to have to start electronically every time.

The singles' crankcase and subsequent "oil pan" are already nicely packed up tight to the bottom of the engine unlike a 4. Therefore, no oil pan modifications are needed, which saves time/money/reliability.

[AxelRipper]

One more thing to add: I dont see how the parts for a single are cheaper and easier to find, at least not the ones that we go through often. For whatever reason, we had a rash of starter clutch failures that DOS mentioned. This is not easy to come by in our area. For whatever reason, it seems as though the parts that we seem to need at the current time are harder to get than parts for our old f4i, but then I remember that the f4i was run from ~2001-06 and there is a massive stockpile of parts accumulated in the shop and with the 450x going on its 3rd year here and not yet having a steady tune, it all makes sense.

it really is 6 of one and half dozen of the other.

and the sound of the f4i, even one running incredibly rich like our old car, is very sweet. The single sounds nice in its own right as well, but its just strange since the pitch changes so little from ~5k to redline

[MH]

I'd like to add something which has been neglected. I agree that it's not the chosen concept that is dominating but the team that builds it. We've seen awesome battles between different concepts last couple of years! That's the nice thing about the rules, there is enough room to choose your own direction.

But having driven both 4s and singles, I'm of the opinion that with regard to setup and handling it's easier to have a lightweight single. It's really underestimated how much 10kg can do, let alone 60!
Of course in the end it's the whole package, all I'm saying is that for non-professional drivers it's easier to handle and find a decent setup for a single then for a 4.
In fact this was the main reason for Delft to choose a single in those days...


regards,
Miki Hegedus
Delft University of Technology 2001-2008

[Bemo]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:
I'd like to add something which has been neglected. I agree that it's not the chosen concept that is dominating but the team that builds it. We've seen awesome battles between different concepts last couple of years! That's the nice thing about the rules, there is enough room to choose your own direction.

</div></BLOCKQUOTE>

That's absolutely right! But I'm afraid that the latest rules changes regarding fuel, less points for acceleration etc. will lead to a point where there is a clear advantage for singles. In my oppinion it is a fatal error to give one concept clear advantages by rule changes because of politics (what is in my oppinion the reason for giving 100 points for fuel). On the long term this will lead to less diversity and less freedom for creativity and therefor to a less attractive competition.

For a very long time we saw only minor rule changes, and if you ask me, that was the right way!

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:

That's absolutely right! But I'm afraid that the latest rules changes regarding fuel, less points for acceleration etc. will lead to a point where there is a clear advantage for singles. In my oppinion it is a fatal error to give one concept clear advantages by rule changes because of politics (what is in my oppinion the reason for giving 100 points for fuel). On the long term this will lead to less diversity and less freedom for creativity and therefor to a less attractive competition.

For a very long time we saw only minor rule changes, and if you ask me, that was the right way! </div></BLOCKQUOTE>

I think the aim of the fuel rules change was more to stimulate teams to think about fuel efficiency. Whether you do that by choosing a single or developing a very efficient 4-cylinder, that's up to the teams. The environment is a hot issue these days and this competition has to change with the world around it.

But to be honest, I think we'll see a dramatic shift to alternative fuels or electric in the near future anyway.

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[Mike Cook]

The fuel economy might have worked if there was a minimum weight. The problem is, I could do all the research and development in the world with a 4, and I'm probably not going to even come close to the fuel economy of a unmodified single. And therefore the team who just chose to go to a single will still get more points for fuel than the team with a radically, innovative, 4 cylinder. Essentially, they are rewarding the big picture concept more than the nuts and bolts of actually getting good fuel economy. And that big picture is saying you need to run the lightest single cylinder car as possible.

The point system basically says: Alright were going to build a single seater race car, but fuel economy is more important than the lateral performance, longitudinal performance, and only 20% less important than the overall on track performance.

Gotcha.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> The environment is a hot issue these days and this competition has to change with the world around it. </div></BLOCKQUOTE>

Last time I checked this was a competition mostly geared towards undergraduate engineers. Also, last time I checked the principles on which all of my classes were based on, have been more or less the same for about 50-100 years. FSAE is about reinforcing these principles. Therefore, I disagree strongly with you.

Mike

[Bemo]

I definitely agree with Mike.

The major goal of FSAE is to give students the opportunity to gain practical experience.
The environmental problems of the future won't be solved by any inventions made in this competition. If we are honest we have to admit that no team really "invents" anything, as there isn't sufficient time for that. It's more about understanding the latest technology and adapting it for the needs of FSAE.

And as Mike said. As there is no minimum weight it is impossible to compete with the singles if you're driving a 4. If the difference of the points is increased there it will lead to a point where it just gets impossible to win a competition with a 4. That would be a shame for this competition as it would mean a great loss of diversity of concepts.

[MH]

Well, the beauty of this forum and the competition is that we don't have to agree. Although I'll try not to sound condescending as some others.

My point I was trying to make is that the environment is changing around us and many companies need engineers who think about their design choices in terms impact on the environment. That means looking at ALL aspects of your design choices.

In all honesty that has been neglected in the past. Look at all the automotive companies that are currently doing research into fuel economic vehicles, alternative fuels and so on. What's wrong with stimulating the FSAE-engineers to think about that a bit more during their time in this competition?

I'm not just talking about the engine-mapping. I'm talking about the smart use of materials, lightweight construction, good loadpaths, simple construction and so on. And plane old thinking about the environmental impact of your choices. (I know I sound like a hippie http://fsae.com/groupee_common/emoticons/icon_wink.gif )

And no, the basic design principles may have not changed, but the importance of some design options during designing sure have. Do we still use wood in airplane wings? No, we've chosen other materials. Do we not keep improving engines? Do we not build cars that are more aerodynamic? The basic principle is still the same, but still we do it...

And I also don't agree that this competition is mainly to gain practical experience. That's what internships are for. This competition is about challenging engineers to think outside the box, to cope with new rules with which you may not agree, getting in touch with the costs side of things, getting organizational skills etc.

Having said that, I'd prefer more points for the Design Event, because that's where you can explain your choices and present your (environmentally) efficient design. There are many forms of good designs.

But like I said, it's nice to have different opinions http://fsae.com/groupee_common/emoticons/icon_smile.gif

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[Bemo]

Hey Miki,

In fact I agree with most of what you said. The problem is that if to many points are given away it gets impossible to win with a 4-cyl car which is well thought through and in fact very efficient against a single cyl car which is kept very basic.
Giving more points for design would be the better way, there you can give the points for everything you said about lightweight design, loadpaths etc. And also these are points which aren't depending on having a good driver.

The problem with that is, that this only works in accordance with a fair and transparent judging, which isn't the case at all competitions. FSG surely is a very good example, what design judging should be like. But in my opinion at quite a lot of competitions this isn't the case at all.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:

The problem is that if to many points are given away it gets impossible to win with a 4-cyl car which is well thought through and in fact very efficient against a single cyl car which is kept very basic.
Giving more points for design would be the better way, there you can give the points for everything you said about lightweight design, loadpaths etc. And also these are points which aren't depending on having a good driver.

The problem with that is, that this only works in accordance with a fair and transparent judging, which isn't the case at all competitions. FSG surely is a very good example, what design judging should be like. But in my opinion at quite a lot of competitions this isn't the case at all. </div></BLOCKQUOTE>

+1 on that. It would be a shame if one concept would have so much clear advantage over the other and it looks (emphasis on looks) like the singles are getting a headstart in the dynamics. Personally I like the battles of the concepts. In the German enduro final there were 2 singles and 2 4s. 3 cars on 10" tyres and 1 on 13". That was cool!

Design Judging is something of an art. Perhaps with some more explanation from what judges are looking for there is a way to make it more fair and transparant?

I think we're a bit off topic though http://fsae.com/groupee_common/emoticons/icon_wink.gif

rgds,
Miki Hegedus
Delft University of Technology 2001-2008

[bob.paasch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mike Cook:
The fuel economy might have worked if there was a minimum weight. The problem is, I could do all the research and development in the world with a 4, and I'm probably not going to even come close to the fuel economy of a unmodified single. And therefore the team who just chose to go to a single will still get more points for fuel than the team with a radically, innovative, 4 cylinder. Essentially, they are rewarding the big picture concept more than the nuts and bolts of actually getting good fuel economy. And that big picture is saying you need to run the lightest single cylinder car as possible.
</div></BLOCKQUOTE>

In an attempt to somewhat follow the original thread, I'm going to refer to low HP verses high HP rather than single verses four. http://fsae.com/groupee_common/emoticons/icon_smile.gif

At the current time, the low HP cars are only dynamically competitive with the high HP cars if they are very light. There were a lot of low HP cars at Michigan that were not competitive. If you've got less than 50 HP, you need to be down under 150 kg, otherwise the high HP cars are going to pull such a lead in accel, autocross and enduro that fuel efficiency/economy won't matter.

Getting down to 143 kg (Delft at FSG) takes a LOT of development. I also would be willing to bet that the best low HP teams did just as much engine development for fuel economy/efficiency as the top high HP teams. You don't just bolt in a 450 motor and get a competitive endurance time and use 2.5 liters of fuel.

In my humble opinion, the pre-2009 scoring favored high HP concepts. Low HP cars were able to win occasionally, but it took an excellent team (2006/07 RMIT) coupled with just a little good luck (2008 Delft).

It remains to be seen whether the current rules have actually shifted the playing field to make it more even, or whether it now favors low HP low weight vehicles. Regardless, it still takes an excellent team coupled with a little good luck to win a major competition.

[Mike Cook]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:
Regardless, it still takes an excellent team coupled with a little good luck to win a major competition. </div></BLOCKQUOTE>

Agreed.

[bob.paasch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:

The problem is that if to many points are given away it gets impossible to win with a 4-cyl car which is well thought through and in fact very efficient against a single cyl car which is kept very basic. </div></BLOCKQUOTE>

The top "low HP" cars are far from "very basic." Just how does a 45 HP car beat a 95 HP car in an FSAE autocross? It's not because the 45 HP car is "basic."

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Giving more points for design would be the better way, there you can give the points for everything you said about lightweight design, loadpaths etc. And also these are points which aren't depending on having a good driver.

The problem with that is, that this only works in accordance with a fair and transparent judging, which isn't the case at all competitions. FSG surely is a very good example, what design judging should be like. But in my opinion at quite a lot of competitions this isn't the case at all. </div></BLOCKQUOTE>

I should probably wait another three weeks before commenting about design judging. I'm not very concerned about fair and transparent design judging at FSAE Michigan, FSAE California, FSUK or FSG. Those competitions have solid groups of knowledgable, experienced judges. Obviously, we've been very pleased with design judging thus far this year, but that said, there will always be some irregularities in judging due to its subjective nature. Delft was second in design at FSUK, yet didn't make design finals at FSG. And we'll see about FSAE Italy... http://fsae.com/groupee_common/emoticons/icon_wink.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:
+1 on that. It would be a shame if one concept would have so much clear advantage over the other and it looks (emphasis on looks) like the singles are getting a headstart in the dynamics. Personally I like the battles of the concepts. In the German enduro final there were 2 singles and 2 4s. 3 cars on 10" tyres and 1 on 13". That was cool!
</div></BLOCKQUOTE>

Second year in a row for 2 singles and 2 fours. http://fsae.com/groupee_common/emoticons/icon_smile.gif http://fsae.com/groupee_common/emoticons/icon_smile.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Design Judging is something of an art. Perhaps with some more explanation from what judges are looking for there is a way to make it more fair and transparant?
</div></BLOCKQUOTE>

Hmmmm, given the presentation on design at FSG and the numerous articles from Pat and Steve on the FSG web site, I'm not sure how much more the chief design judges could do as far as explanation.

[Demon Of Speed]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bemo:
I definitely agree with Mike.

The major goal of FSAE is to give students the opportunity to gain practical experience.
The environmental problems of the future won't be solved by any inventions made in this competition. If we are honest we have to admit that no team really "invents" anything, as there isn't sufficient time for that. It's more about understanding the latest technology and adapting it for the needs of FSAE.

And as Mike said. As there is no minimum weight it is impossible to compete with the singles if you're driving a 4. If the difference of the points is increased there it will lead to a point where it just gets impossible to win a competition with a 4. That would be a shame for this competition as it would mean a great loss of diversity of concepts. </div></BLOCKQUOTE>

The FSAE cars from an environmental aspect burn very little fuel (we got 22 mpg in endurance). They are designed to race in an autocross environment where you do not need to pit for fuel (no advantage for fuel economy), and it is usually raced on weekends, the FSAE car would burn less fuel per year than a prius (if you owned both).

Additionally, I know of a team that ran a catalytic converter at competition to say "hey we are trying to be environmentally friendly" and got zero interest from the design judges for it. It would seam that if fuel economy was for the environment that some points should have been awarded for the proper design and fitment of a cat on a FSAE car.

I still think that design should be after the dynamic events, that way if you are slow/fast in an even you have to justify why to the judges and if your car fails then you have to explain your there as well. I have seen many concept the the design judges like that have either not lived up to what the team said or have failed entirely.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:
Hmmmm, given the presentation on design at FSG and the numerous articles from Pat and Steve on the FSG web site, I'm not sure how much more the chief design judges could do as far as explanation. </div></BLOCKQUOTE>

If it's all so transparent and fair, then how come for Delft there is a 45+ points difference in score in Design within FSUK and FSG? I know that they had the same team members and nothing changed on the car between comps. In fact some of the judges were the same in both comps. It seems to me that certain aspects of design such as innovation/carry-over, attention to detail, lightweight construction and even costs have different weight factors in different competitions when it comes to scoring during Design. And I'm not convinced that's because there were a lot of other cars, because that wasn't really the case this year.

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[TMichaels]

In FSG the motto is, as far as I know : "We judge your knowledge, not your car". In FSUK it seems to be very often only about the car itself (things you can look at). Maybe that is one of the main differences. This was my experience in 2008. Maybe it changed.

Regards,

Tobias

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Demon Of Speed:
It would seam that if fuel economy was for the environment that some points should have been awarded for the proper design and fitment of a cat on a FSAE car.
</div></BLOCKQUOTE>
Cats make fuel consumption worse, not better, as you cannot run lean. They are fitted to reduce pollutants during 'gentle' driving.

The lack of interest of the Design Judges may be because for a typical motorsports engine tune the cat is just dead weight. If the team does not realise this, it shows up a lack of knowledge.

Regards, Ian

[murpia]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:
In FSG the motto is, as far as I know : "We judge your knowledge, not your car". </div></BLOCKQUOTE>
That is also the briefing given to the FSUK design judges. Whether it happens in practice will depend on the individuals involved.

I was luck enough to judge Delft in 2009 and GFR in 2010. Both teams showed outstanding knowledge and were scored accordingly.

Note that a moderation process is applied following the individual judging teams scoring.

Regards, Ian

[blister]

Don`t be so damn serious.

We once had a design score difference of 55 points in 2008...between FSG and FS Italy. 95 in FSG and 150 in Italy

Concering Horsepower/weight: As we are building now electric cars maybe a more neutral position:

Look at the rules, do the calculations and you will see that there is no way you could win dynamics + fuel with a 4 clyinder assuming both drivers use the same % of the car`s potential.

Don`t forget the extra points in cost for less parts/less material. Also low weight is what brings you at least 10-20 points in Design (assuming the rest of the car is equally well done)

So why we never switched to a singly cylinder:
50% fear of the new (mostly justified due to time constraints and manpower)
50% emotional reasons (sound, revs, racy)

I talked to a lot of members of german top 15 finisher teams and NO ONE has given me a good reason why they don`t switch.

[TMichaels]

Don't get me started with respect to design judging in Italy in terms of seriousness http://fsae.com/groupee_common/emoticons/icon_smile.gif

Regards,

Tobias

[MH]

+1.
Half of those guys don't even speak English.

[Brian McGreevy]

One of the things our team (and probably many) have done for the last few years is tune for overall power usability. This leads to a very broad and flat torque curve from 7k all the way up to 11k. The throttle response is fantastic, as well. Peak power is ~75 bhp. This is for an F4i.

On the subject of fuel economy, I have a similar opinion to most of you here. The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. I doubt this rule will change anytime soon, however. What I would like to see is a normalized fuel economy based on displacement. This would tend to show the teams that did the best job with their chosen configuration (which I think should be the point of the fuel portion of endurance).

[blister]

you just have to speak italian to them ;-)

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
On the subject of fuel economy, I have a similar opinion to most of you here. The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. I doubt this rule will change anytime soon, however. What I would like to see is a normalized fuel economy based on displacement. This would tend to show the teams that did the best job with their chosen configuration (which I think should be the point of the fuel portion of endurance). </div></BLOCKQUOTE>

+1

[Old Greg]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. </div></BLOCKQUOTE>

Tell that to Audi or Peugeot. In fact, tell that to any Formula 1 or MotoGP team.

[Pennyman]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Old Greg:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. </div></BLOCKQUOTE>

Tell that to Audi or Peugeot. In fact, tell that to any Formula 1 or MotoGP team. </div></BLOCKQUOTE>

If you mean our endurance should be twice as long and have another driver change and a refueling maneuver, that would be interesting. But then it wouldn't really be geared to the weekend autoX'er would it?

Addressing the original topic, I think the course layout has a huge impact on whether hp (or even power-to-weight) matters. A better question might be which courses suit high hp and which suit low hp?

[MalcolmG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Old Greg:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. </div></BLOCKQUOTE>

Tell that to Audi or Peugeot. In fact, tell that to any Formula 1 or MotoGP team. </div></BLOCKQUOTE>

I agree with this strongly, and consider it to be perfect justification for the increased value of fuel economy.

10% improvement in fuel economy, and therefore required fuel load, is only worth maybe 0.3-0.6kg in FSAE, but in F1 for instance it could be more like 15kg, and presumably even more in enduro racing. In addition, in something like Le Mans it could add up to several minutes of time on track because you didn't have to pit as frequently to refuel.

Real race cars benefit from reduced fuel consumption a lot more than an FSAE car would in dynamic events, so having a high weighting on fuel economy doesn't concern me at all, it's just unfortunate for teams with a strong attachment to the larger engines who feel it makes them no longer competitive.

[Brian McGreevy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Old Greg:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The idea to make fuel economy, for a race car, more important than acceleration or skidpad is simply ridiculous. </div></BLOCKQUOTE>

Tell that to Audi or Peugeot. In fact, tell that to any Formula 1 or MotoGP team. </div></BLOCKQUOTE>

I never said fuel economy isn't important, I said to make it more important than fundamental dynamic performance is silly. An F1 or MotoGP or Le Mans team would also agree. There is no point in any of those series saving a lot of fuel if you are miles off the pace. If they do indeed chop 25 points off acceleration this year, it sends a clear message that this is no longer about using the best engineering principles to design a weekend autocross car. No one cares about fuel economy in autcross.

I am also not trying to 'hold on' to any particular design or engine, but I agree with those who said that SAE is artificially pushing all teams in one direction by making fuel economy worth so much relative to most of the dynamic events. Like I said before, if you normalized fuel based on displacement, I wouldn't care much about it being 100 points (though I still think it's too much).

[MalcolmG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:
If they do indeed chop 25 points off acceleration this year, it sends a clear message that this is no longer about using the best engineering principles to design a weekend autocross car. No one cares about fuel economy in autcross.
</div></BLOCKQUOTE>
One could argue that a 75m acceleration time or G's pulled on a skidpad are as irrelevant in autocross as fuel economy is, because all that really matters is how fast the car can go around an autocross style track, and whether it does that while being able to do well in straight-line acceleration is neither here nor there.

Edit: while I'm here, I disagree with the notion of normalising fuel economy for engine displacement. Fuel economy is hardly directly proportional to engine displacement, maybe normalising it for power output so you're actually looking at thermal efficiency would be fairer, but still overly complicated to implement IMO.

[Mike Cook]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:

One could argue that a 75m acceleration time or G's pulled on a skidpad are as irrelevant in autocross as fuel economy is, because all that really matters is how fast the car can go around an autocross style track, and whether it does that while being able to do well in straight-line acceleration is neither here nor there.
</div></BLOCKQUOTE>

Since at the very least, in an autocross, the vehicle starts from 0mph, improving longitudinal acceleration would always improve lap time.

[flavorPacket]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:
If it's all so transparent and fair, then how come for Delft there is a 45+ points difference in score in Design within FSUK and FSG? </div></BLOCKQUOTE>

The car supports the students. If a student has an 'off' day or simply does not know answers to questions the judge asks, the judge cannot award as many points as to a student who can answer all the questions.

In addition, not all judges ask the same questions. So in the very little time available in the design event, not all areas of the student's knowledge can be evaluated in equal depth (or maybe even at all).

When you think of design from the judge's standpoint, I think it becomes pretty clear how to be successful in the design event.

[MalcolmG]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Since at the very least, in an autocross, the vehicle starts from 0mph, improving longitudinal acceleration would always improve lap time. </div></BLOCKQUOTE>
but that is covered by the autocross event, so why have a separate event that rewards you solely for straight line acceleration? I'm certainly not advocating that the accel event should be dropped (as the only dynamic event my team managed to win, I think it should be worth at least 600 points...), I'm just providing the other side of the argument (because that's what I do).

[VFR750R]

As time goes on and today’s engine side FSAE'ers become tomorrow’s seasoned engine engineers, fuel economy will only become more important. It's really better preparing you for a job in the industry which is the real purpose of FSAE, not a make-believe SCCA autocross car.

I'm of the thought that fuel economy is an important design constraint for ALL internal combustion engines, both racing and production. It doesn't bother me that they raised the points for fuel economy. I also don't think it means the death of the 4 cylinder engines.

Most teams I've talked to either used generalizations when mentioning fuel economy (we used a single cylinder, we're running leaner then best power, etc.) or had not considered it all. One hint for those of you who haven't figured it out; you don't have to run the same A/F ratio all weekend or at all operating points.... And if you did something that you think improved fuel economy, bring data to prove it. One of the easiest things to test at a practice lot...ever.

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by flavorPacket:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:
If it's all so transparent and fair, then how come for Delft there is a 45+ points difference in score in Design within FSUK and FSG? </div></BLOCKQUOTE>

The car supports the students. If a student has an 'off' day or simply does not know answers to questions the judge asks, the judge cannot award as many points as to a student who can answer all the questions.

In addition, not all judges ask the same questions. So in the very little time available in the design event, not all areas of the student's knowledge can be evaluated in equal depth (or maybe even at all).

When you think of design from the judge's standpoint, I think it becomes pretty clear how to be successful in the design event. </div></BLOCKQUOTE>

+1

Judges are also influenced by the level of competition which is never the same, and almost always gets better. It's not practical to compare design scores from two separate events.

[VFR750R]

I hope they don't remove acceleration points.
The other events do not reward engine performance to the amount real racing does and this event allows proper weighting (IMHO) to be added to offset the slow autocross and endurance courses required for safety and limited by space.

If the cars were run on courses more representative of their size and capabilities, engine performance would have a more significant impact in lap times.

[Brian McGreevy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:
If they do indeed chop 25 points off acceleration this year, it sends a clear message that this is no longer about using the best engineering principles to design a weekend autocross car. No one cares about fuel economy in autcross.
</div></BLOCKQUOTE>

Edit: while I'm here, I disagree with the notion of normalising fuel economy for engine displacement. Fuel economy is hardly directly proportional to engine displacement, maybe normalising it for power output so you're actually looking at thermal efficiency would be fairer, but still overly complicated to implement IMO. </div></BLOCKQUOTE>

While it may not be directly proportional, it should have a strong correlation.

For instance:
A good fuel economy usage for a top 1 cyl team is 0.650 to 0.700 gallons.
A good fuel economy usage for a top 4 cyl team is 0.850 to 0.900 gallons.

0.700 / 450 = 0.00155
0.900 / 600 = 0.00150

You could argue that both of these engines were tuned for very similar A/F ratios and performance relative to their size based on these numbers. It would still be fair to the teams who worked very hard on economy (the ones using 0.5 to 0.6 gal), and punish the ones that didn't. But it also wouldn't cripple the teams who spent time optimizing an endurance-specific map for the best compromise between speed and economy.

[Demon Of Speed]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MalcolmG:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:
If they do indeed chop 25 points off acceleration this year, it sends a clear message that this is no longer about using the best engineering principles to design a weekend autocross car. No one cares about fuel economy in autcross.
</div></BLOCKQUOTE>

Edit: while I'm here, I disagree with the notion of normalising fuel economy for engine displacement. Fuel economy is hardly directly proportional to engine displacement, maybe normalising it for power output so you're actually looking at thermal efficiency would be fairer, but still overly complicated to implement IMO. </div></BLOCKQUOTE>

While it may not be directly proportional, it should have a strong correlation.

For instance:
A good fuel economy usage for a top 1 cyl team is 0.650 to 0.700 gallons.
A good fuel economy usage for a top 4 cyl team is 0.850 to 0.900 gallons.

0.700 / 450 = 0.00155
0.900 / 600 = 0.00150

You could argue that both of these engines were tuned for very similar A/F ratios and performance relative to their size based on these numbers. It would still be fair to the teams who worked very hard on economy (the ones using 0.5 to 0.6 gal), and punish the ones that didn't. But it also wouldn't cripple the teams who spent time optimizing an endurance-specific map for the best compromise between speed and economy. </div></BLOCKQUOTE>

The analysis of the two engine might work, if the single and 4 were the same weight when they ran the endurance. This would just promote people using 4's if they knew the rest of the car was going to be heavy.

If you want to look at the efficiency of the engine (due to good tuning) then look at the BSFC. This as mentioned this would be very trick to measure.

[Brian McGreevy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Demon Of Speed:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:

While it may not be directly proportional, it should have a strong correlation.

For instance:
A good fuel economy usage for a top 1 cyl team is 0.650 to 0.700 gallons.
A good fuel economy usage for a top 4 cyl team is 0.850 to 0.900 gallons.

0.700 / 450 = 0.00155
0.900 / 600 = 0.00150

You could argue that both of these engines were tuned for very similar A/F ratios and performance relative to their size based on these numbers. It would still be fair to the teams who worked very hard on economy (the ones using 0.5 to 0.6 gal), and punish the ones that didn't. But it also wouldn't cripple the teams who spent time optimizing an endurance-specific map for the best compromise between speed and economy. </div></BLOCKQUOTE>

The analysis of the two engine might work, if the single and 4 were the same weight when they ran the endurance. This would just promote people using 4's if they knew the rest of the car was going to be heavy.

If you want to look at the efficiency of the engine (due to good tuning) then look at the BSFC. This as mentioned this would be very trick to measure. </div></BLOCKQUOTE>

I think the point on the weight is void. If the single and the 4 were the same weight, I doubt anyone would run the single, as that is BY FAR its largest advantage. The singles are best when paired with an equally light car. Yes they'll have low fuel consumption regardless, but they'll also likely have great dynamics scores if quite light. If a team had a very heavy car, this would increase fuel consumption regardless of which engine chosen. Even if you put a 4 cyl in a heavy car, there's a good chance it will be worse off than a much lighter 4 cyl car. I don't see what the problem is there.

True on the BSFC, but as you reiterated, very hard to measure unless all cars were dyno'd. Even then, they would have to make sure teams used the same map as they did in endurance and that would be very hard to police.

[Old Greg]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:
No one cares about fuel economy in autcross. </div></BLOCKQUOTE>

You previously made a blanket statement about all race cars, and that's what I took exception to.

[Xeilos]

This is partly for those people who have actually participated in an autocross outside of FSAE (you know, in the real life marketplace that we are trying to 'sell' these racecars in).

If you ask someone at the end of the day of autocrossing what they would rather have, FTD (Fastest Time of the Day) or the car with the bragging rights saying you used the least amount of fuel but you did not get FTD. You can guess what they would choose...

These are not truly mutually exclusive objectives but if you had to choose, which one would you rather go for. If you chose fuel economy, you are in the wrong series (I will be flamed for saying this) but you need to go join FSAE-Electric or maybe your local solar car team. http://fsae.com/groupee_common/emoticons/icon_wink.gif

Ultimately, in the end its not about how much fuel you consumed to get from Point A to B; what is ultimately important is how short(or conversely how long) it took you to get from Point A to B. Bear in mind, what the consumer of these racecars would like to see.

I am not arguing fuel economy is not an important concept in the overall big picture especially in endurance (LeMans) or F1, but this car is aimed at a "weekend autocross'er". If you want to word the intent of this competition differently to better match the 'real' racing series, do so but realize it will change the intent of the competition itself and the focus of what each team does.

Some people need to realize that FSAE is not LeMans nor F1 nor MotoGP or any of those other racing classes, it is by itself in its own class with it's own objectives and rules. How often do people really directly compare F1 and say LMP1 cars side by side? Its like comparing a McLaren F1 to a Toyota Yaris (it does not make real sense and the comparison is not really valid).

Sorry for the rant today, but the importance we are putting on fuel economy for a FSAE-class racing car is in my opinion ridiculous and is compromising the intent of this competition in its current form.

[MH]

I think Xeilos' story shows exactly the difference in opinion about what the top level aim of the competition is.

I really think the FSAE competition is NOT about developing the quickest weekend-racer. In my opinion it's about creating better ENGINEERS. How? By giving them a challenge. Developing a weekend racer is a CASE, nothing else. Why a weekend racer as a case? Because it's probably more fun and appealing than designing a coffee machine.

And how do you prepare the engineers for real life the best? By changing the rules of the case every now and then, to meet the real world's challenges, because the world changes around us as well. And the world needs engineers who can cope with changing regulations or laws and changing challenges such as the climate problem.

Engineers should be flexible, creative, not afraid to think outside the box, able to see the big picture and take on any engineering challenge they meet in real life. They should NOT become experts in designing a quick weekend-racer.

That's how I see the competition anyway. But feel free to disagree http://fsae.com/groupee_common/emoticons/icon_smile.gif

regards,

Miki Hegedus
Delft University of Technology 2001-2008

[TMichaels]

+1
The weekend autocrosser is only the story to have a cause to build a car, nothing else. The purpose is, in my opinion and how we handle it in FSE, to enhance the abilities of future engineers.
Otherwise nobody with electronic gadgets, a monocoque, a car built to last one season or a car with the current pricing would have ever been able to win design. This is not meant as criticism to the teams having electronic gadgets (like we had) or teams building monocoques! PLEASE don't start discussing about this or flame me! This was only a comparison between the story and how it is currently handled.

Regards,

Tobias

[Brian McGreevy]

While I fully agree that FSAE has a primary purpose to further the development of future engineers, I still believe that there has to be a premise defined. Most passenger cars are designed for good fuel economy and comfort, with enough power to satisfy its usual conditions. Race cars are designed to be as fast as possible, but without burning so much fuel to make its speed for nothing. FSAE has to define the design premise we as engineers make assumptions on. The business portion is about marketing to a weekend autocross customer. The design portion is about using the best skills to define your goals and use analysis, data and good judgment to execute those goals in the best way possible. I will admit that this leaves it completely open to interpretation and that is a fantastic part about FSAE. The dynamic events are about going as fast as possible. The lion's share of the points currently resides with these areas, and in general, most of the fastest cars score well in design. At this point, the underlying premise appears to be an examination of a team's ability to design and successfully fabricate a purpose-built race car.

Rumored changes to the points structure (25 for skidpad, 50 for accel) will undermine this premise, as it will increase the importance of fuel economy to a point where you either design a race car, or an eco car.

[Xeilos]

The rules say:

The intended sales market is the nonprofessional weekend autocross racer. Therefore, the car must have very high performance in terms of its acceleration, braking, and handling qualities. The car must be low in cost, easy to maintain, and reliable”

Again, the above story is the purpose and the 'drive' (excuse the pun) behind why we are building this car. That is not to say I am encouraging ignoring the engineering portion of the competition and the side effect of helping everyone become a better engineer; that is also another facet of the competition.

But this competition is the practical application/outlet of an overly theoretical eduction in engineering. That word practical by itself represents the application of what we have learned to a 'real life' situation or event. This leads back to the fact that we are building a race car that someone might actually like to buy. No one is going to buy a race car in real life that is slow but has good fuel economy if ceter parablis (everything else remaining equal especially and specifically price) another alternative is available that is faster but gets worse fuel economy. Then again people DO buy Prius's! http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

Now looking at the engineering side of it, we all love new technology and the latest gadgets. That is what makes us what we are and alot of the time drives us to pursue otherwise stupid ideas in the name of innovation and that 'coolness' factor. We want a car that has high horsepower [a) it sounds good on paper and b) the performance benefit], returning briefly to the initial topic of discussion of this forum thread, and also one that handles well and uses some new technology that has trickled down from some upper-echelon of racing. We also need to be adaptable (as MH said) to an ever changing world as engineers.

Ultimately, I think the best car is one that is the fastest in all aspects and does so with the least fuel consumed. This is what we all strive for, regardless of engine choice, and is the concept that is creating the element of competition to...well...this competition. I just would hate to see an even further shift to focus on fuel economy at the expense of the performance measures/events of this competition.

P.S. Do not take offence to anything I say. I love extemperaneous debates and the discussion of these issue with like-minded and equally intelligent people brings in new perspectives and ideas; ultimately this enlightens everyone despite anyone disagreeing with a specific point of view.


<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Brian McGreevy:

Rumored changes to the points structure (25 for skidpad, 50 for accel) will undermine this premise, as it will increase the importance of fuel economy to a point where you either design a race car, or an eco car.
</div></BLOCKQUOTE>

+1 for the above point of view

[Seeger]

To address the comments that say that the engine side of the competition needs to better reflect the OEM design goals. If that is true then; A). shouldn't the suspension design reflect mainly around the McPherson strut as it is the most common suspension design. B). that frame design should focuses mainly on NVH isolation and dampening. C). That all cars should have an aerodynamics package of which it's sole purpose would be drag reduction.

The list goes on and to make the argument that we don't design for fuel economy as well as higher echelon racing i.e. F1, Le Mans, Moto GP is entirely true. But we also do not design any of our systems to the level the same level as racing series in the real world. Their are many reasons for this they get paid, there are a hell of a lot more of them working on every part, they don't have to go to classes, do homework and such.

The reason for my rant is to say that to make fuel economy more important than most of the rest of the cars overall design would mean that teams structures would have to change to reflect the change in points, more people designing the engine subsystem. I for one appreciate the fact the currently most systems have similar importance or weight in the overall design process. To change the rules in a way that might make the competition based more on one system seems like it would let down the team work aspect that employers want from the formula sae series.

just my view point feel free to point out the flaws of my logic

[EHog]

Unless you can find me a car that has won Auto-X AND Fuel Economy ON THE SAME MAP... I will not be satisfied.

A weekend autocrosser wants to go AS FAST AS THEY CAN at ALL points in time. Is it a good idea to change the map for different events in order to win this competition? Yes of course! Would the average weekend autocrosser, or any autocrosser for that matter say to oneself... "I want to go a tad slower so that I can save a nickel"? I dare you to find someone that would say this.

In a post above, there is a quote out of the rules. "Very high performance in terms of acceleration, braking, and handling qualities"

If even 0.01 seconds can be gained by throwing a bit more fuel in the cylinder, I cannot see a way to justify not doing such a thing.


There are TWO types of FSAE cars... IC and Electric. Why don't we leave the environmental aspects up to the electric dudes? I would hate to see this turn in to more of a supermileage competition than a racing competition. If that is the case though, I think we might just set up shop in Al Gore's backyard...

[TMichaels]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">There are TWO types of FSAE cars... IC and Electric. Why don't we leave the environmental aspects up to the electric dudes? I would hate to see this turn in to more of a supermileage competition than a racing competition. If that is the case though, I think we might just set up shop in Al Gore's backyard... </div></BLOCKQUOTE>

The main purpose of Formula Student Electric is not to be green. That's why we use exactly the same points distribution like the combustion events and do not add points to economy for example. Maybe you are mixing us up with the Formula Hybrid or Class1A

Regards,

Tobias

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:

Maybe you are mixing us up with the Formula Hybrid or Class1A

Regards,

Tobias </div></BLOCKQUOTE>


Absolutely correct. I was mixing you up with formula hybrid.

[3-Phase]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:

Maybe you are mixing us up with the Formula Hybrid or Class1A

Regards,

Tobias </div></BLOCKQUOTE>


Absolutely correct. I was mixing you up with formula hybrid. </div></BLOCKQUOTE>

Surprisingly, Formula Hybrid does not have an economy event. There are no points for efficiency. The rules provide you with a specific, set energy allotment limit, and your team is free to use that entire amount of energy without penalty or reward.

-Russell

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by 3-Phase:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by TMichaels:

Maybe you are mixing us up with the Formula Hybrid or Class1A

Regards,

Tobias </div></BLOCKQUOTE>


Absolutely correct. I was mixing you up with formula hybrid. </div></BLOCKQUOTE>

Surprisingly, Formula Hybrid does not have an economy event. There are no points for efficiency. The rules provide you with a specific, set energy allotment limit, and your team is free to use that entire amount of energy without penalty or reward.

-Russell </div></BLOCKQUOTE>

My mind has been blown. Hybrids not giving an economy score???? I think from now on, the prius should come with a sticker in the window that says "freakin good mileage" rather than an actual EPA number.


Instead of economy, they should just give us (FSAE IC) a max amount of fuel. The benefit of not needing much is that fuel is around 7 LBS PER GALLON!!! Is that not reason enough to attempt to use less fuel?

[Thrainer]

I can't understand why you're discussing and argueing about the intent of FSAE. I have never seen a weekend autocross and don't think that a big portion of the roughly 300 FSAE cars built each year get to run at weekend autocrosses regularely.

I for myself have three main reasons to participate: 1. Learn. 2. Do well at competition. 3. Have fun.

To do well at competition, you have to earn as many points as possible. When choosing your concept, you have to decide for yourself if you can afford to loose a lot of points in a certain area (be it cost, acceleration or efficiency).

Now to the thread topic "Horsepower". Last year before competition, I was certain that our "roughly 55 kW for 200 kg" Simplon would loose a lot of fuel efficiency points against the "roughly 30 kW for 150 kg" DUT09, but very confident that we would more than make up the deficit in acceleration, autocross and endurance. Well, I was shocked when both Delft and Oregon scored more than 90/100 points in autocross against the exceptional Stuttgart drivers (and left us far behind). On the other hand, I didn't expect us to be only 6 points behind Oregon in fuel efficiency, with a 4 cylinder and only one map (on E85, though).

Then this year, Delft comes back to FSG and wins Autocross, Endurance and Fuel Efficiency. At Silverstone, they ran one second faster than Monash and TU Munich in Autocross ("Sprint").

Now I have to read here along the lines of "the rules are favouring slow eco cars". Simply not true, these light single cars are efficient AND fast.

I am under the impression that many teams don't choose their concept objectively. If your last year's concept is not competitive under the new rules, then it's not the rules that have to stay the same, but your concept that has to change (if you want to do well at competition).

I hope some electric cars will do very well compared to the ICE cars next near. Not because they have more (horse-) power, but more control and a good balance of power and weight (energy storage). Instead of going from a 4 cylinder to a single, we went directly to electric http://fsae.com/groupee_common/emoticons/icon_smile.gif

Regards,
Thomas
Powertrain ETH Zurich 2008-2010

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Thrainer:
I have never seen a weekend autocross and don't think that a big portion of the roughly 300 FSAE cars built each year get to run at weekend autocrosses regularely.
</div></BLOCKQUOTE>

We do http://fsae.com/groupee_common/emoticons/icon_cool.gif

Its almost more fun than comp because we slaughter everything by 6-10 seconds! All the real life "weekend autocrossers" stand by the curb and giggle like little girls! Oh, how they wish they could have a FSAE car http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[Brian McGreevy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Thrainer:
Now to the thread topic "Horsepower". Last year before competition, I was certain that our "roughly 55 kW for 200 kg" Simplon would loose a lot of fuel efficiency points against the "roughly 30 kW for 150 kg" DUT09, but very confident that we would more than make up the deficit in acceleration, autocross and endurance. Well, I was shocked when both Delft and Oregon scored more than 90/100 points in autocross against the exceptional Stuttgart drivers (and left us far behind). On the other hand, I didn't expect us to be only 6 points behind Oregon in fuel efficiency, with a 4 cylinder and only one map (on E85, though).

Then this year, Delft comes back to FSG and wins Autocross, Endurance and Fuel Efficiency. At Silverstone, they ran one second faster than Monash and TU Munich in Autocross ("Sprint").
</div></BLOCKQUOTE>

Keep in mind that most FSAE teams have nowhere near the budget to develop and build a car like that. You pretty much have to have a monocoque to get that kind of speed out of a single-cylinder car.

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Seeger:
To address the comments that say that the engine side of the competition needs to better reflect the OEM design goals. If that is true then; A). shouldn't the suspension design reflect mainly around the McPherson strut as it is the most common suspension design. B). that frame design should focuses mainly on NVH isolation and dampening. C). That all cars should have an aerodynamics package of which it's sole purpose would be drag reduction.

just my view point feel free to point out the flaws of my logic </div></BLOCKQUOTE>

Maybe we should. Although one could argue that there are new cars out there with double wishbone suspension, frames built for weight and stiffness, and aero packages with downforce in mind. But, no new engines are designed without fuel economy and/or emissions as a consideration. Even weed-wackers and snowmobiles are 4 stroke now.

I wouldn't be opposed to almost any rule change that doesn't change the fundamentals of the competition. (Forcing teams to rethink their engine choice is not a fundamental change) I know most teams are invested in the current rules, most teams are, but that's not necessarily a good thing. Right now, most teams can use previously acquired knowledge (which is how the real world works), but in the real world the rules change sometimes too.

[thewoundedsoldier]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
My mind has been blown. Hybrids not giving an economy score???? I think from now on, the prius should come with a sticker in the window that says "freakin good mileage" rather than an actual EPA number. </div></BLOCKQUOTE>

FSE and Formula Hybrid are not about going the longest distance given a set time and set energy. They are about completing a set distance with set energy in the fastest possible time.

The distinction is pretty important and, in my opinion, is why FS is changing. Those who have trouble accepting changes like this are doomed to stay stationary while the ones who accept the change will drive forward.

Some day a team will make comparable endurance lap times on half as much fuel...the organizers are just trying to give us incentive to get there.

My $0.02.

[BrandenC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:
Some day a team will make comparable endurance lap times on half as much fuel...the organizers are just trying to give us incentive to get there.

My $0.02. </div></BLOCKQUOTE>

Yea, but what will they be driving, 180lb shifter karts?

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BrandenC:
they be driving, 180lb shifter karts? </div></BLOCKQUOTE>

+1 http://fsae.com/groupee_common/emoticons/icon_smile.gif

Some of the cars are starting to look more and more like go karts. Not cool if you ask me.

Note: Not cool does not imply not fast

[Pete Marsh]

Do those teams that don't cross the Atlantic realise the fuel event is scored differently in FSG and FSAE?

The FSG formula includes enduro time and is actually an efficiency score. A much better system IMO. It still doesn't make any difference while teams like RMIT, and now Delft, can win enduro anyway, but still much more in tune with the whole idea of FSAE than the USA formula just giving more points for low use of fuel regardless of performance in enduro.

As regards to the OP, once you add a driver, especially 95th percentile, even the 50KG advantage doesn't totally make up for the power loss of the single. I don't believe the 4 cylinder concept is dead,it should still be a faster car,and disagree with your points analysis if you do. (for FSG scoring!)

I put it to you that Delft is that quick because of other factors to make an overall competitive concept.
Specifically, in order to make the single cylinder concept win you must compromise strength and durability, safety/comfort, drivability, and maintenance/service intervals.
All in the name of fuel economy, and even then with FSG rules a good 4 can still win, it's no where near a done deal for a single.
For those that have had a close look at a UWA or Stuttgart car, and one of the quick singles, make an honest assessment of which concept you think would survive in a real autocross/hill climb world and be able to be bashed and crashed by its owner. We have crashed our car, and it is very strong. I'm happy to sit in it on a road with consequences, can you say that about you're car?

If a 145kg single wins because of a superior fuel score its because the 195kg 4 didn't sell the concept good enough in pres and design. As far as the track events, the 4 should have a slight edge, 25 points maybe, but perhaps Delft simply out raced everybody on the day by more than that. Drivers and testing is worth way more than 25 points.

Time will tell, but I seriously doubt we will see total domination by WR450 powered machines from now on, although I fully agree they may win more often than before.

Pete

[oz_olly]

I think far too many people get distracted by the fact they think they are designing an autocross car. Sure that is the context within which the rules are written but there is a fair bit of difference between autocross regulations and FSAE competition rules. At the end of the day we are all designing "FSAE CARS".

If you want to win FSAE, thoroughly analyse and understand the rules, develop a concept, come up with detailed solutions to meet your concept, manufacture them and then tests and adjust. Reading too much into the weekend autocross racer can lead you into making design decisions that may make the car a better weekend autocross car and a worse FSAE car. Designing for raw outright speed with no consideration for fuel economy is a great example of this. Like others have said this Engineering Project Realisation competition is put in the theoretical context of desiging an autocross car to attract students interest, it could just as easily be a wheel barrow comp. If so you would design the best wheel barrow to maximise your points score, not the one that will do the best job of moving your firewood from the shed to your house (providing your goal is to have the best possible SAE Wheel Barrow competition entry and not something to use at home after the comp).

[MH]

I think there is still a lot of sentiment or emotion involved when it comes to design choice. Of course 4-cyl turbo charged engines with 100bhp are cool. But it should not be the decisive factor. Well, not if you ever want to win the comp. It doesn't hurt to re-analyse the rules (and your competition!) and re-set your goals.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Thrainer:
I hope some electric cars will do very well compared to the ICE cars next near. Not because they have more (horse-) power, but more control and a good balance of power and weight (energy storage). Instead of going from a 4 cylinder to a single, we went directly to electric http://fsae.com/groupee_common/emoticons/icon_smile.gif

Regards,
Thomas
Powertrain ETH Zurich 2008-2010 </div></BLOCKQUOTE>

Well Thomas,

I think next season we'll see some interesting battles between Combustion and Electric cars. It is rumoured (not officially confirmed) that one or more of the teams mentioned above will switch to electric. http://fsae.com/groupee_common/emoticons/icon_cool.gif

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[TMichaels]

I heard the same rumours...It should really give the competition another boost if some more teams decide to switch. This year's event showed that the FSE cars are really competitive. Not to mention that they usually had less power and were heavier compared to the IC cars.

BTW: We plan to release a document containing the major rule changes for FSE2011 at the end of this week.

Regards,

Tobias

[Kirk Feldkamp]

I'd like to pose a question to those in this discussion that have data acquisition in their cars. How fully are you able to utilize your engine power? It's one thing to have 90 hp, but it's an entirely different thing to actually use that power often. I've seen a number of different data sets from various FSAE competitions in the US, for both singles and well tuned 4 cylinders. Throttle histograms of the data show a large proportion of time is spent at low and mid throttle. You can hear it on FSAE videos on YouTube too. This is in stark contrast to the outcome when the same cars are run at full size SCCA autocross events, where a significantly higher amount of time is spent at full throttle. If you haven't done this analysis before, prepare to be shocked. The singles tend to have much higher proportions at high throttle postions, which makes perfect sense. Does anyone care to post some histograms from their autocross or endurance runs at comp? How about for a SCCA autocross?

My point is that FSAE competition tracks tend to be so tight that arguing about weight vs. horsepower can be a null argument to some degree. Personally, I think it's *easier* to drive a car that's not as capable of overpowering the rear tires all the time. The balancing act you get into with an over-powered, under-gripped car is much tricker to drive than a car that you can lead foot a larger proportion of the time. Essentially, the traction limited power output vs. throttle position resolution is better with the lower power situation. If you were running a high speed autocross or road racing car, I would pick more power any day... but that's not really how FSAE competitions are laid out.

-Kirk

[bob.paasch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kirk Feldkamp:
I'd like to pose a question to those in this discussion that have data acquisition in their cars. How fully are you able to utilize your engine power?
</div></BLOCKQUOTE>

Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Big Bird]

Kirk, that is EXACTLY the argument we based our design decision on all those years ago. In fact, my personal ambition was to keep reducing the engine size and output until we found that balance point between controllability and speed.

I still think the 450 is a bit abrupt off low throttle, and I have a feeling the current crop of mid sized enduro thumpers (Husky 310, KTM350, etc) might be the ideal choice. But it was hard enough to convince a team to drop back to 450 - and once we got there the desire to overcompensate for the percieved "loss" took over.

Agreed with Bob's data, 15-20% full throttle time is pretty typical.

Cheers all

[thewoundedsoldier]

Excellent point, Kirk.

Throttle position histograms should really be the answer to this thread.

I would wet my pants if I saw a 350 at comp! Please please please someone do it!

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:

Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

We have frequently seen 20% and sometimes more with our 4 cylinder.

There is much more to drive-ability then not having a lot of power. The way the engine delivers the power is far more important. It has to be predictable and the engine has to have a very good throttle response.

[Neil_Roberts]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:

Throttle position histograms should really be the answer to this thread. </div></BLOCKQUOTE>

Maximizing points should really be the answer to this thread. Determining the optimum global set of compromises that will maximize a team's points potential is one of FSAE's primary engineering education opportunities.

Given the seemingly endless variety of design variables and their interactions, I'm surprised by how rare the use of lap time simulators seems to be. Design judges want to see engineering-quality objective evaluations of design alternatives. Hand-waving rationalizations are not engineering.

When evaluating options, it is often helpful to consider the extremes. A tiny 5 hp engine is easy the way to maximize the throttle histogram, but it will probably shift the maximum points potential away from the optimum for the overall event.

So what is the optimum compromise? Study the rules carefully, fire up the sim, and find out.

[Mikey Antonakakis]

Is this thread about how to win a competition? That assumes you're already on a top-level team. Is it about how a mid-level team can improve? Or how a new team should start?

As some people have mentioned, seat time, test time, and driver skill are worth a whole lot in this competition, at least for most teams. That is, after being able to finish endurance at all. We didn't finish, but considering the amount of testing time and suspension tuning we had on our car before competition (virtually none), and our driver skill level (that'd be me, and I don't claim to be a good driver), we were doing fairly well before we blew a cooling hose. Also, simple things such as throttle bore I'm sure would have a significant impact on a throttle position histogram.

I know this has been beat into the ground, but the fact that both singles and 4's win dynamic events, with singles usually getting better economy, shows there's no clear advantage to either strategy, and it comes down primarily to team management. The more professional-looking teams are usually the ones winning, and I don't think there's any coincidence there. The lack of a clear advantage by design philosophy is what makes this competition so awesome.

[thewoundedsoldier]

Neil, I think you may have ignored the very first post in this thread.

EHog: "My question is, how much power do teams have? How much do you believe this helps times?"

I don't see anything about points optimization. I agree it is important and should be done, but this thread is about how POWER affects LAP TIMES.

[Mikey Antonakakis]

Oh and to answer the original question, I think the answer from one of the consistently fastest teams tells all. They have a high-power car, but stress the importance of having good control of that power.

[thewoundedsoldier]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Neil_Roberts:
When evaluating options, it is often helpful to consider the extremes. A tiny 5 hp engine is easy the way to maximize the throttle histogram, but it will probably shift the maximum points potential away from the optimum for the overall event. </div></BLOCKQUOTE>

A 5HP engine would not have a T.P. histogram. It would be a straight line along the number "100" of the y-axis. Similarly, a 120HP engine would show a very slightly waving line around 5-10%. Those curves, in themselves, are answers to how power affects lap times. It highlights that there is an optimal solution somewhere for each different car.

[woodsy96]

Rather interesting thread. We began this year by trying to quantify how many points 1hp was worth (among other things) to our overall competition performance to decide out where we should allocate our resources and to work out what our goals for the year were.

For those who don't know, last year our team swapped from a Supercharged 600cc 4 cylinder (which won acceleration at FSAE-A 2008) to a NA 450 single (which IIRC the last or second last classified car in acceleration at FSAE-A 2009).

Our driver's complained lots about a lack of power last year. Admittedly the track in 2009 was a lot more open than 2008, so the apparent problem was probably compounded.

On the throttle position, our data suggests that we are running a lot higher than "a typical FSAE/FS track": around 40% of the lap last year was at 100% throttle. A lap from Autocross in heat 2 is below.

http://i308.photobucket.com/albums/kk323/woodsy96/TPShistogram.jpg

Making a quick simulation to work out how much time you think you can gain by adding x% more power isn't very hard using a couple of suitable assumptions. Just don't forget that at the end of the straight you will be travelling faster and hence need a longer braking zone.

Our simulations suggest that each extra hp we gained was worth [sensored] seconds per lap in autox and [sensored] seconds per lap in endurance and worth [sensored] seconds in Acceleration, which works out as an extra [sensored] points overall. I would be interested to compare this to other peoples conclusions if they have done similar analysis to see if they reached similar conclusions. But I don't want to just give our results out.

[TMichaels]

As mentioned before a throttle histogram is only helpful to optimize your concept, be it single or 4 cylinder as the bore of your throttle body heavily affects this histogram and may, if too big, lead to a histogram never reaching 100% throttle except for straights.

Another thing which is important is to deactivate traction control, if you are planning to evaluate your throttle histogram. Should be trivial, but has to be mentioned. Otherwise you may collect data, which produces a diagram which is in average significantly higher.

Regards,

Tobias

[Kirk Feldkamp]

Ok ok, fair enough. It's not really the throttle histogram that you care about per se, it's whatever it means with regard to power generation that you care about. The histogram is more of a quick indicator most tuners could use to demonstrate the point. One basic way to get to the heart of the issue would be to have dyno data at the various part throttle positions, and perform a calculation that translates the TP and RPM at any given time in the driving data into a power number. From there you could do a power histogram to analyze how often the driver actually uses the available power. A more accurate, direct method would be to use torque sensors on the drive axles, because the available traction would be taken into account. Regardless, I'm going to go out on a limb and say the overall outcome of the analysis will probably remain the same.

RenM, it sounds like you guys have already worked through the important part of this analysis. Driveability is the key, and that can be achieved through a variety of methods. The concept I'm suggesting is that it's not ultimate power that you're after in FSAE, it's excellent control of that power. Furthermore, having that extra power doesn't necessarily buy you much by way of points at comp. The easier things are to control, the easier it will be for the drivers to drive (especially relatively untrained drivers). My assertion is that this will tend to yield more points on average at comp than having a big power number.

Ultimately, this always gets back to the resources discussion. Time. Money. Manpower. Stuttgart, OSU/GFR, and a few handfuls of other teams have significant resources available to them (I think), so their methods may not apply to the average team. If you don't have a ton of resources available, the question becomes how can you get the biggest points bang for your resource buck? Does it make more sense to run a high power system if you have to use significant resources dumbing it down so it's more useable? Or, does it makes sense to be able to put an "underpowered" system in and be able to flat foot it more often? As you suggest, Geoff, there is probably a sweet spot somewhere, and most everyone is potentially still above that level. I would suggest that in the end, less resources would be used by coming from the other direction. Starting small and working up would eliminate most of the tricky driveability engineering that needs to be done on the other path. It's a fair bit easier to simply add power with off-the-shelf parts than it is to do the detailed driveability engineering. Here in the US, we don't have a lot of 350 models that I know of. We do, however, have a lot of 250X's and WR250's. The stock 250's are around 34hp, and heavily modified ones are around 43hp. I'd post the link, but that would take forever to get approved. Go to RonHamp dot com and look at the dyno section. The first one at the top of the list is what I'm talking about. Hey TheWoundedSoldier, what would you do if someone showed up at comp with a screamin' 250? http://fsae.com/groupee_common/emoticons/icon_wink.gif

Neil, I agree that points at comp is the real goal here. The hard part about simulations is that the inputs are notoriously difficult to get right. What's traction coefficient of the tires, what's the load at each contact patch, what's this, what's that... the reality is everything is dynamic, and to get any sort of fidelity to the real world requires a ton of resources. Testing also requires a ton of resources, but at least you're accounting for the real world variations in the variables. There is a time and a place for both. Geoff's often talked about lap sims provided a good "jumping off point" for RMIT to make the switch to the 450. He'll be the first to admit, however, that those models were pretty basic, and had somewhat limited capability (Geoff, please chime in if I'm full of it). An F1 team has the resources to account for all of the real-world variations, and testing is limited per the rules, so they rely heavily on simulations for their designs. This is yet another case where the rules of the game dictate how your resources should be spent. My take is that most FSAE teams rarely do enough driving/testing as it is, so any excuse to actually test should be a priority.

As with most racing, the proof is in what happens out on track. The objective of what I originally wanted to point out is that the reality of the situation when driving is far different than the assumptions that are made about it. It's a funky concept to get your head around at first... going faster on average in certain situations may be achievable by spending fewer resources on making power. Have an older 450 car just sitting around? Stick a 250 in there and do some tests. I dare you! http://fsae.com/groupee_common/emoticons/icon_smile.gif

Anyone outside of your own team telling you need more power in FSAE is smart. RenM, I'm looking at you! It's always a smart strategy to trick your competitors into thinking that they need to spend a disproportionate amount of resources on something that doesn't generate a whole lot of points in the end!

-Kirk

[RenM]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kirk Feldkamp:
Anyone outside of your own team telling you need more power in FSAE is smart. RenM, I'm looking at you! It's always a smart strategy to trick your competitors into thinking that they need to spend a disproportionate amount of resources on something that doesn't generate a whole lot of points in the end!
-Kirk </div></BLOCKQUOTE>

Its simply our design philosophy to have a good power to weight ratio while other teams philosophy is to build an extremly light car. There is nothing wrong about both. You can win and do good with both concepts.
And i dont think that Delft or OSU will switch back to a 4 cyl because i am defending using one here on the forums http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Neil_Roberts]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:
Neil, I think you may have ignored the very first post in this thread.

EHog: "My question is, how much power do teams have? How much do you believe this helps times?"

I don't see anything about points optimization. I agree it is important and should be done, but this thread is about how POWER affects LAP TIMES. </div></BLOCKQUOTE>

My post above is one of the few in this thread that offered EHog an objective, engineering-oriented means to answer his own question. I'd call that directly on-topic.

The older I get, the more I appreciate the value of clearly stated principles and objectives. I have become far more interested in why we do things than what we do. So, I feel the need to clearly establish, at least for myself, the fundamental reasons underlying my actions. Thus the points discussion. It also serves as a reminder that it is easy to lose sight of your big picture priorities while debating any sub-topic extensively.

One of the fundamental priciples that I live by, and that I wrote about in Think Fast, is "Don't guess when you can know". It doesn't take a high-fidelity lap sim to produce good-enough results for giant changes like engine selection.

Of course, if lap sims are not an option, there are other ways to determine fuzzy but useful indications of relationships among variables. Many years of event results, and the basic specs of the cars that produced those results, can be a goldmine waiting to be analyzed.

I fully agree that track testing is more valuable than sims for many reasons, but it's the beginning of the year for everyone. Unless track testing every engine option, and optimizing the design of the car for each option, is the plan, then lap sims are an attractive and practical alternative means to guide the decision making process.

[Kirk Feldkamp]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
There is nothing wrong about both. You can win and do good with both concepts.
And i dont think that Delft or OSU will switch back to a 4 cyl because i am defending using one here on the forums http://fsae.com/groupee_common/emoticons/icon_wink.gif </div></BLOCKQUOTE>

Haha, no intentional criticism at all. I respect Stuttgart's decisions because (A) you can justify them, and (B) you have made it work in practice. If you have the resources to do it your way, then more power to you! I just wanted to point out that the alternative path could reduce a newer team's resource requirements.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:
It doesn't take a high-fidelity lap sim to produce good-enough results for giant changes like engine selection.

I fully agree that track testing is more valuable than sims for many reasons, but it's the beginning of the year for everyone. Unless track testing every engine option, and optimizing the design of the car for each option, is the plan, then lap sims are an attractive and practical alternative means to guide the decision making process.
</div></BLOCKQUOTE>

You'll get no argument from me in this regard. The question is what you do after the first time you go through the lapsim justification process. Either you spend lots of time building more fidelity into your models, or you can think about the data you already have in different ways. If you're smart about the "new" car designs each year, then you're going to iterate on the previous car to some extent, so real world test data would generally prove more useful than a basic simulation at that point. The intent of my post was to point out that it's not necessarily power to weight ratio that tells the whole story for a FSAE car. Unconventional thinking about engine power and the data you have in your hands already can save you a lot of time, money, and manpower. Given that a couple of the fastest single cylinder FSAE teams on the planet weighed in and both said they don't even use all their available juice a large amount of the time suggests to me that there may still be an opportunity to free up program resources beyond what the 450's already do. That may or may not work well on track... so I'm just putting it out there for you guys to think about.

-Kirk

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:


Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

So you're saying 15-20% of the time you could use more HP http://fsae.com/groupee_common/emoticons/icon_wink.gif

Seems like most people are assuming low WOT times means you have too much power...I would say the exact amount of power that leads to 0% WOT time is the right amount http://fsae.com/groupee_common/emoticons/icon_smile.gif That's what the throttle is for!

[GianVioli]

Hey I'm gonna take a wild guess that just came up to my mind.

If we consider the acceleration event, and take into account that most of the difference in times is done in the first 20-25 meters of it. You can say that NOT much difference can be made on a stragiht if you are not starting from 0 speed, which is the case in Endurance and AutoX. BUT, we do face a lot of corners, and since we dont spent too much time in corners (I think F-SAE is all about corner entry and corner exit), is takes logic that this is a Handling competition!.

What do you guys think?

[J. Vinella]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:


Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

So you're saying 15-20% of the time you could use more HP http://fsae.com/groupee_common/emoticons/icon_wink.gif

Seems like most people are assuming low WOT times means you have too much power...I would say the exact amount of power that leads to 0% WOT time is the right amount http://fsae.com/groupee_common/emoticons/icon_smile.gif That's what the throttle is for! </div></BLOCKQUOTE>

Is there anybody hear that would like less horsepower from their car?

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Vinella:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:


Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

So you're saying 15-20% of the time you could use more HP http://fsae.com/groupee_common/emoticons/icon_wink.gif

Seems like most people are assuming low WOT times means you have too much power...I would say the exact amount of power that leads to 0% WOT time is the right amount http://fsae.com/groupee_common/emoticons/icon_smile.gif That's what the throttle is for! </div></BLOCKQUOTE>

Is there anybody hear that would like less horsepower from their car? </div></BLOCKQUOTE>

It's pretty obvious there is just one solution. An engine as light as a 450 single with the power of a turbo 4. Personally, I hate compromise http://fsae.com/groupee_common/emoticons/icon_smile.gif

[thewoundedsoldier]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Vinella:
Is there anybody hear that would like less horsepower from their car? </div></BLOCKQUOTE>

We are so far off topic it is crazy. I know a lot of people who would want to spare 1 hp for 5 kg of weight.

EHog's original question focused on two teams who were similar in weight, and pointed out that drastic differences in horsepower did not necessarily produce time differences on the track.

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:

We are so far off topic it is crazy. I know a lot of people who would want to spare 1 hp for 5 kg of weight.

EHog's original question focused on two teams who were similar in weight, and pointed out that drastic differences in horsepower did not necessarily produce time differences on the track. </div></BLOCKQUOTE>

Yeah, it happens. But back on topic, both of those cars had wings and they finished 1-2 in auto-x....I think we have been focusing on the wrong part of the original post.

[J. Vinella]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by thewoundedsoldier:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Vinella:
Is there anybody hear that would like less horsepower from their car? </div></BLOCKQUOTE>

We are so far off topic it is crazy. I know a lot of people who would want to spare 1 hp for 5 kg of weight.

EHog's original question focused on two teams who were similar in weight, and pointed out that drastic differences in horsepower did not necessarily produce time differences on the track. </div></BLOCKQUOTE>

Exactly. I was trying to get us back on topic. All this talk of CCs and weight.

But to go to the original question, just based on the weight and hp which car would you take?

[J. Vinella]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
I hate compromise http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

Me too.

This thread could go on with a myriad of different directions. Wings or no wings, aim for torque or top end power, single or twin or 4 banger or 0.5L V8, what weigh is necessary to get heat into the tires for auto-x http://fsae.com/groupee_common/emoticons/icon_confused.gif http://fsae.com/groupee_common/emoticons/icon_biggrin.gif, based on hp/engine sections what tires should I use, fuel economy and has the SAE chosen to take points from accel guiding this comp towards the Fuel Mileage competition... http://fsae.com/groupee_common/emoticons/icon_frown.gif

Yes, thank you, I'll take double the HP for a ~3% increase in weight.

Why the times are not more different? Driver skill, compliance between the two cars, how well the cars are setup. Or maybe HP and weight are not the only factors... http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif Given two sample points it is hard to judge performance.

[Mikey Antonakakis]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:


Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

So you're saying 15-20% of the time you could use more HP http://fsae.com/groupee_common/emoticons/icon_wink.gif

Seems like most people are assuming low WOT times means you have too much power...I would say the exact amount of power that leads to 0% WOT time is the right amount http://fsae.com/groupee_common/emoticons/icon_smile.gif That's what the throttle is for! </div></BLOCKQUOTE>
Which crazy 60s or 70s racer was it that said he'll never have enough power until he can spin the tires in top gear at the end of a straight (paraphrasing).

[Mike Cook]

M. Donohue

[DFT]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
1st place auto-x at FSAE WEST had ~96HP and the car weighed ~425 with wings.

2nd place auto-x at FSAE WEST had ~48HP and the car weighed ~413 with wings.

How much relavance do the facts above have to the question I am asking below? Probably very little but I just thought I would inform...

-Evan </div></BLOCKQUOTE>

I think the only way you could make any solid conclusions from this is if there where no significant differences between the cars besides for power and if both drivers got the maximum (or at least similar percentages) out of the cars, which seems pretty unlikely.

As far as the power difference is concerned, it seems pretty large either way, but is the 48HP your quoting at the wheels or crank? Because the 96HP is at the crank.

[EHog]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DFT:
As far as the power difference is concerned, it seems pretty large either way, but is the 48HP your quoting at the wheels or crank? Because the 96HP is at the crank. </div></BLOCKQUOTE>

Crank. Once again, 48 is not certain. You may read why in an earlier post.

[jerry_tung]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by woodsy96:
Rather interesting thread. We began this year by trying to quantify how many points 1hp was worth (among other things) to our overall competition performance to decide out where we should allocate our resources and to work out what our goals for the year were.

For those who don't know, last year our team swapped from a Supercharged 600cc 4 cylinder (which won acceleration at FSAE-A 2008) to a NA 450 single (which IIRC the last or second last classified car in acceleration at FSAE-A 2009).

Our driver's complained lots about a lack of power last year. Admittedly the track in 2009 was a lot more open than 2008, so the apparent problem was probably compounded.

On the throttle position, our data suggests that we are running a lot higher than "a typical FSAE/FS track": around 40% of the lap last year was at 100% throttle. A lap from Autocross in heat 2 is below.

http://i308.photobucket.com/albums/kk323/woodsy96/TPShistogram.jpg

Making a quick simulation to work out how much time you think you can gain by adding x% more power isn't very hard using a couple of suitable assumptions. Just don't forget that at the end of the straight you will be travelling faster and hence need a longer braking zone.

Our simulations suggest that each extra hp we gained was worth [sensored] seconds per lap in autox and [sensored] seconds per lap in endurance and worth [sensored] seconds in Acceleration, which works out as an extra [sensored] points overall. I would be interested to compare this to other peoples conclusions if they have done similar analysis to see if they reached similar conclusions. But I don't want to just give our results out. </div></BLOCKQUOTE>
33% of 0% throttle was not done by a good driver.

[jerry_tung]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Vinella:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:


Typical FSAE/FS track, our car is a full throttle 15-20% of the time. That's with 45 HP. http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

So you're saying 15-20% of the time you could use more HP http://fsae.com/groupee_common/emoticons/icon_wink.gif

Seems like most people are assuming low WOT times means you have too much power...I would say the exact amount of power that leads to 0% WOT time is the right amount http://fsae.com/groupee_common/emoticons/icon_smile.gif That's what the throttle is for! </div></BLOCKQUOTE>

Is there anybody hear that would like less horsepower from their car? </div></BLOCKQUOTE>
it depends on which car can accelerate faster. you were assuming the 4 is faster on the straight weren't you.

[J. Vinella]

Jerry,

I was not assuming that, you were assuming that I as assuming something I was not assuming. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

I was talking about from your car, as whatever package you have, single, 4 banger, 0.5L V8...

Take the car you have now and add HP...I'd take that. Per the original post.

I understand why the topic was posted and it stimulates interesting debate. But when the cars weight very close to the same weight it makes it kind of a self evident. (Granted we are looking at just peak HP)

[jerry_tung]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by J. Vinella:
Jerry,

I was not assuming that, you were assuming that I as assuming something I was not assuming. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

I was talking about from your car, as whatever package you have, single, 4 banger, 0.5L V8...

Take the car you have now and add HP...I'd take that. Per the original post.

I understand why the topic was posted and it stimulates interesting debate. But when the cars weight very close to the same weight it makes it kind of a self evident. (Granted we are looking at just peak HP) </div></BLOCKQUOTE>
haha, you are right.

[thewoundedsoldier]

When someone tries to quantify how much 1HP is worth, aren't they looking for how much 1HP is worth in terms of X amount of mass, X amount of time, X amount of money, or X amount of anything else.

We'd all take extra HP if it was free, but how much is it worth to you?

[williams13nr]

Nice thread, lots of good points and differing opinions.

I did not see anywhere in here bringing up the point that more weight will be more load on tires, and thus more force is possible. This tends to balance the actual accelerations of the two cars. I have not looked at the tire data, and do not know to what extent this increases the traction, but is potentially another factor.

Also, sorry to bring up an older part of the thread, but in FSAE Michigan this year, 2 4 cylinder cars were 1 and 2 in fuel economy, and both used under .6 gallons. I can speak for Villanova who was making 65 hp at the wheels, and ran a 4.37 in accel with the same map as enduro. Lap times are down in enduro and autoX, but this was largely due to lack of driver testing time and car setup IMO.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by williams13nr:
Also, sorry to bring up an older part of the thread, but in FSAE Michigan this year, 2 4 cylinder cars were 1 and 2 in fuel economy, and both used under .6 gallons. I can speak for Villanova who was making 65 hp at the wheels, and ran a 4.37 in accel with the same map as enduro. Lap times are down in enduro and autoX, but this was largely due to lack of driver testing time and car setup IMO. </div></BLOCKQUOTE>

That comparison is really bad. Villanova took 5.6 minutes longer to complete endurance than GFR (for whatever reason), which makes their average speed a lot lower. Approx 64kph for GFR compared to 50kph for Villanova. Of course you will burn less fuel, air drag goes up squared with the speed and rolling resitance increases too...
This is the reason its should be fuel efficiency which takes into account you enduro time. In theory I could just optimize my speed to win the Fuel Economy by driving really slowly. If I'm in the slow group, nobody will take me off course for not obeying the 133% rule...I know that for some teams this is their goal.

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[Thomas MuWe]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:

That comparison is really bad. Villanova took 5.6 minutes longer to complete endurance than GFR (for whatever reason), which makes their average speed a lot lower. Approx 64kph for GFR compared to 50kph for Villanova. Of course you will burn less fuel, air drag goes up squared with the speed and rolling resitance increases too...
This is the reason its should be fuel efficiency which takes into account you enduro time. In theory I could just optimize my speed to win the Fuel Economy by driving really slowly. If I'm in the slow group, nobody will take me off course for not obeying the 133% rule...I know that for some teams this is their goal.

regards,
Miki Hegedus
Delft University of Technology 2001-2008 </div></BLOCKQUOTE>

Sorry Miki,

cannot agree with that. Lets think about the case that one car gains the time during cornering....I do not know the villanova car from this year nor the GFR car this year. But what I know is that GFR has pretty damn good drivers.
So I assume that the minimum speed during cornering is higher for GFR. As a result they do not have to accelerate as hard as Villanova and as a result do not have to use the same amount of energy to get the same speed at the end of the straight as GFR. So the problem in maybe not the inefficiency of one car or the other. The problem is that one car has not the best drivers where the other car has it. IMO the fuel efficiency thing is definetely unfair. But that are just my 2 cents!

[Zac]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by MH:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by williams13nr:
Also, sorry to bring up an older part of the thread, but in FSAE Michigan this year, 2 4 cylinder cars were 1 and 2 in fuel economy, and both used under .6 gallons. I can speak for Villanova who was making 65 hp at the wheels, and ran a 4.37 in accel with the same map as enduro. Lap times are down in enduro and autoX, but this was largely due to lack of driver testing time and car setup IMO. </div></BLOCKQUOTE>

That comparison is really bad. Villanova took 5.6 minutes longer to complete endurance than GFR (for whatever reason), which makes their average speed a lot lower. Approx 64kph for GFR compared to 50kph for Villanova. Of course you will burn less fuel, air drag goes up squared with the speed and rolling resitance increases too...
This is the reason its should be fuel efficiency which takes into account you enduro time. In theory I could just optimize my speed to win the Fuel Economy by driving really slowly. If I'm in the slow group, nobody will take me off course for not obeying the 133% rule...I know that for some teams this is their goal.

regards,
Miki Hegedus
Delft University of Technology 2001-2008 </div></BLOCKQUOTE>

You know you are so dangerously close to making the case for aero.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Thomas Müller-Werth:

So I assume that the minimum speed during cornering is higher for GFR. As a result they do not have to accelerate as hard as Villanova and as a result do not have to use the same amount of energy to get the same speed at the end of the straight as GFR. </div></BLOCKQUOTE>

That sounds a bit strange to me. Are you implying that the top speed on the straight of both Villanova and GFR are the same?
I agree that a smooth driver probably uses less fuel than an aggressive driver. I also agree with you that the cornering speed of GFR was probably higher (thus higher resistance), but that underlines my statement because there are far more corners than straights. That speed has to come from somewhere if you look at the energies involved. If you win 5.6 minutes over another car, the chance is quite big that your speed is higher everywhere and therefore have a higher aero resistance and roll resistance.

@Zac: I don't know what you mean, but if my intention was to win Fuel in Michigan I'd think about a decent aero package to reduce drag and drive as slowly as I can get away with http://fsae.com/groupee_common/emoticons/icon_wink.gif

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by williams13nr:
Nice thread, lots of good points and differing opinions.

I did not see anywhere in here bringing up the point that more weight will be more load on tires, and thus more force is possible. This tends to balance the actual accelerations of the two cars. I have not looked at the tire data, and do not know to what extent this increases the traction, but is potentially another factor.

</div></BLOCKQUOTE>

That would be F=muN. I think everyone would agree with you except mu varies slightly as a function of N. So a 10lb increase in N will not necessarily create a linear increase in F. This is why weight is so important on real race cars which have way less tire/weight ratio then we do in FSAE.

[Zac]

If FSAE speeds are high enough that aero drag becomes a significant factor, they're also high enough that downforce becomes a significant factor.

[MH]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Zac:
If FSAE speeds are high enough that aero drag becomes a significant factor, they're also high enough that downforce becomes a significant factor. </div></BLOCKQUOTE>

Let's not confuse reducing drag on a car with generating downforce + additional drag. Downforce is not for free unfortunately.

Developing a useful downforce generating aero package takes a lot of time and money. Besides, the rules don't really favor sharp edged wings, so you're not exactly free to do everything.

But I think we've seen good examples of aero packages doing well at comp. Usually not in fuel though http://fsae.com/groupee_common/emoticons/icon_smile.gif

regards,
Miki Hegedus
Delft University of Technology 2001-2008

[RenM]

Kinetic Energy is defined as:
E=1/2*m*v^2
You can see 2 things:
If the speed is the same the mass is the deciding factor (1 cyl car vs 4 cyl car with same speed e.g.).
If the speed is not the same it has a huge influence on the Energy needed because its squared. With same efficiency and weight slower teams, that lift throttle on the straights, will use much less fuel.

Rolling and Aero resistance is rather unimportant compared to the energy being used for acceleration.

TMW:
your argumentation doesnt work, because you imply that because GFR is fast round the corners they lift throttle on the straights because they are fast enough anyways. I think they use their full engine potential on the straight like anyone does who wants to go fast.

The slight differences in cornering speed dont matter that much, because if u assume both teams had the same engine power, they would both go full throttle on the straights and use almost the same amount of energy. The difference is they will reach different top speeds.

[flavorPacket]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:

That would be F=muN. </div></BLOCKQUOTE>

Only for a very good driver. For the other 99.99%, the equation is F &lt;= mu*N.

[Thomas MuWe]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:

TMW:
your argumentation doesnt work, because you imply that because GFR is fast round the corners they lift throttle on the straights because they are fast enough anyways. I think they use their full engine potential on the straight like anyone does who wants to go fast.

The slight differences in cornering speed dont matter that much, because if u assume both teams had the same engine power, they would both go full throttle on the straights and use almost the same amount of energy. The difference is they will reach different top speeds. </div></BLOCKQUOTE>

[Thomas MuWe]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by RenM:

TMW:
your argumentation doesnt work, because you imply that because GFR is fast round the corners they lift throttle on the straights because they are fast enough anyways. I think they use their full engine potential on the straight like anyone does who wants to go fast.

</div></BLOCKQUOTE>

Hehe, no! I assume that the other car can accelerate faster and reaches the same speed at the end of the straight (which means 4-cyl compared to one)!
My whole post was a provocative one! :-)

And you are right: E = 0.5*m*v^2. So if there is a delta v which means different cornering speed and you want to make that up on the straight you have to put in more energy. And then think about the mechanical efficiency of a ICE......

[RenM]

you would have to have a really really bad drivers to explain such a time difference by slower cornering drivers....

[Thomas MuWe]

Of course 5 minutes are far too much to explain by slower cornering drives. This should just be an example....

[williams13nr]

Right, as it has been said here in the past, there are many more factors that contribute to lap times chassis, overall weight, and driver as we mentioned, to name a few.

I think someone mentioned though, that GFR no doubt had faster cornering speed, and this will produce a faster time largely independent of fuel consumption. That is one car needs to break less and carry more speed through a corner when both cars are not on the throttle. They both then floor it on a straight until the next corner to repeat. These two cars would be using similar ammounts of fuel, all other things considered equal in efficiency terms, but one would be much faster. I would tend to think this has a larger effect on the consumption/speed ratio than aero drag on our tracks would.

[Tom W]

There are some assumptions being made in this energy argument that I'm not sure I buy (essentially the energy argument has an inherent assumption of constant time on the straights), mostly because I spent a long time arguing a similar point with a former team member.

The argument we were having was wether we wanted power or torque. On the power side of the argument was that the purpose of the engine is to give a delta E on the straight and that dE=Pdt with t presumably being roughly constant so the higher power engine provides the greater delta E and is therefore the better engine. This argument then continues that power is proportional to airflow so you want to run a Wollongong/Cornell style turbocharged four cylinder and choke the restrictor throughout your operating range.

The torque argument runs that the wheel sees a torque from the engine the torque generates a force and that the tyre and the car only cares about the force that is being applied to it F=ma and whoever has the highest torque has the greatest acceleration and gets to the end of the straight quickest. This argument extends to say that since it is torque that matters for lap time you don't care what the power is for elapsed time. To maximise fuel economy you should then use the engine that generates torque at the lowest RPM point so that you can minimise power and fuel consumption, this leads you to a NA Ape or single cylinder.

Neither of us ever completely managed to convince the other of which argument was correct and in the end we gave up. The only assumption that I can see in either argument that possibly throws an argument into doubt is the elapsed time being constant in the power argument. I'm curious which method people are throwing into their points/lap time sims and if anybody has quantified the differences between the two analysis approaches?

[L B0MB]

Power is the answer Tom W

Torque is not the driving factor as it needs to be provided at a given road speed which if you work back through the gearing will give you a crankshaft speed. Crank torque time rotational velocity equals power.

Talking in power units removes any confusion of gearing in the drivetrain.

A lower power engine will use less fuel but will be slower... IF the track is open enough that a high percentage of time is spent at max power and the lower weight does not provide sufficient gains in braking and cornering

[flavorPacket]

Why don't you guys just run a 90 bhp 4-banger on two cylinders and find out by testing?

[VFR750R]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by L B0MB:
Power is the answer Tom W

Torque is not the driving factor as it needs to be provided at a given road speed which if you work back through the gearing will give you a crankshaft speed. Crank torque time rotational velocity equals power.

</div></BLOCKQUOTE>

Agreed.

Power is most important. Torque by itself is almost meaningless. A flat torque curve is often misrepresented as powerband width which is not the same thing. If you have a wide gap between gears, poor driver, etc., you need a wide powerband, not wide torque band.

For the doubters, create a rear wheel force vs speed graph for your engine in each gear plotted against a curve of constant HP equal to your max HP. The graph will tell you where to shift http://fsae.com/groupee_common/emoticons/icon_smile.gif

[J. Vinella]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by L B0MB:
Power is the answer Tom W

Torque is not the driving factor as it needs to be provided at a given road speed which if you work back through the gearing will give you a crankshaft speed. Crank torque time rotational velocity equals power.

</div></BLOCKQUOTE>

Agreed.

Power is most important. Torque by itself is almost meaningless. A flat torque curve is often misrepresented as powerband width which is not the same thing. If you have a wide gap between gears, poor driver, etc., you need a wide powerband, not wide torque band.

For the doubters, create a rear wheel force vs speed graph for your engine in each gear plotted against a curve of constant HP equal to your max HP. The graph will tell you where to shift http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

Now take that plot and add the max tire force you can produce. Then see how much HP you can get away with and at what gearing.

[Kirk Feldkamp]

Power shows up as a 1/X function on a vehicle speed vs. thrust force graph. Your gearing shifts and scales the gear cascades along the "iso-power" curves. The power output at any given RPM does not change with changes in gearing.... but the forces do. The difference between the vehicle drag curve (make some estimates and plot it) and the thrust curves is the sum of your forces that accelerate the vehicle (duh). It doesn't take a whole lot of time to figure out that either a 'heavy' 4 cylinder car or a 'light' single car can be traction limited for most of the FSAE competition speed range by playing with final drive ratios. Within the traction limited portion of the speed range, you will not realize any more acceleration if you add torque or power through changes to your engine or gearing... you just don't have the ability to put down any more force than the tires can handle!

The trade off you make with your gearing is, of course, vehicle speed for a given engine RPM. Given that FSAE courses are *generally* pretty tight and therefore slow, the speed range you care about is relatively small (compared to even a street car, and especially a "real" track/race car). In other words, if you can find an engine that cranks out some RPM but doesn't make a lot of juice, you can probably end up being traction limited (or close to it) for a significant portion of the speed range you need at comp just by playing with the gearing. The offroad 250 singles make about 34hp and 19ft*lbs and rev out to ~13000rpm [stock], right? Now how about modified a bit to add some top end? How about a UTA-style turbo 4-cylinder 250 (low torque but high power) revving to 19,500rpm? Some quick calculations can tell you what the realities and possibilities are for these, or any other, engine package. Make sure you are taking into account the weight differences between the different setups. http://fsae.com/groupee_common/emoticons/icon_wink.gif

What are some maximum top speeds you top-team guys have ever seen at a FSAE competition in autocross or endurance?

This is all a very non-standard line of thinking, and for very good reason. As soon as you step outside of the realm where the tracks are super tight and low speed, the amount of time you spend outside of the traction limited speed range increases significantly (hence my earlier question about throttle position histograms). In that case, I'll take more power and speed range nearly every time. Within the FSAE realm, I see an opportunity to decrease engine displacement (to a point) without suffering too much with regard to performance. Furthermore, because the economy score has such a direct impact on the points earned equation (10%, right?), the perceived performance losses you get by reducing power and torque are likely more than made up in the economy calculation. The indirect effects of going to a lighter package (improvements in tire wear, lower inertias, etc.) permeate into other areas, but most of the points improvement will likely be seen in autocross and endurance where having an ultra nimble car (transitionally) that doesn't fall off can be a huge benefit.

In the end, this is all an optimization-based argument. Can you get the same amount done with less? This is "engineering" in a nutshell... figuring out ways to meet or exceed goals with the least amount of resources as possible.

-Kirk

[VFR750R]

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For those without budgets, the best FSAE engine ever may have just arrived.

[Homemade WRX]

Oh an engine debate is always fun, especially when it starts with so many variables with different cars (and DRIVERS) but only power and weight are only a small part of the picture.

I'm with Kurt as a big fan of the 250 4-cylinder engines. Hence I had purchased 3 of them for my senior project. I'm actually going to pick up 3 more MC22 engines to turn into my own fun project and build on my existing 92 hp platform. Looking to build a personal FSAE car as I miss driving them http://fsae.com/groupee_common/emoticons/icon_wink.gif

There will always be people to argue for a larger displacement engine being better because of the torque. I'm a fan of usable RPM, gearing and weight. Complexity does play a role, especially with limit funds and knowledge/ability. Those last details can be a real issue for a young or novice team.

[nowhere fast]

I'm not sure if that MV engine will actually end up being 600cc, if it was many potential customers would just buy the Daytona 675 instead.

[Mikey Antonakakis]

Yeah didn't that link say their sources tell them it's going to be 675?

EDIT:
Okay so if you don't have a budget I guess decreasing that displacement a bit is a possibility.

[RANeff]

MV Agusta... *drool*. I was hoping that engine would be 600cc for a while, but looks to be untrue. I suppose if you have enough m oney to buy the enigne, you should have enough to reduce displacement...

[cvargas]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by bob.paasch:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by EHog:
1st place auto-x at FSAE WEST had ~96HP and the car weighed ~425 with wings.

2nd place auto-x at FSAE WEST had ~48HP and the car weighed ~413 with wings.
</div></BLOCKQUOTE>

... and the 3rd place Autocross at FSAE West had ~45 HP and the car weighed 325 with an undertray. http://fsae.com/groupee_common/emoticons/icon_smile.gif

The same car without the undertray was 2nd in autocross at FSAE Michigan, 1st at FSUK, 2nd at FSG, and 4th at FSA.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
My question is, how much power do teams have?
</div></BLOCKQUOTE>

GFR, not much... http://fsae.com/groupee_common/emoticons/icon_smile.gif

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
How much do you believe this helps times?
</div></BLOCKQUOTE>

As Steve and Pat are fond of saying, this is a handling competition, not a power competition.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">
Also, a fundamental question that I simply do not know the answer to... Why was a restrictor of 19/20mm implemented? Was it a safety precaution or more of an engineering design challenge?
</div></BLOCKQUOTE>

The restrictor was implemented primarily a safety precaution, but it certainly has worked out to be a nice design challenge.

My question for you, if you're only getting 48 HP out of that Ape, why bother? The 450 singles are cheaper, simpler, and lighter. </div></BLOCKQUOTE>

I wish people at my school would understand that.

[nowhere fast]

http://www.twowheelsblog.com/p...re-eicma-show-wvideo (http://www.twowheelsblog.com/post/5457/mv-agusta-f3-breaks-cover-before-eicma-show-wvideo)

MV Agusta have confirmed that the F3 engine is 675cc; however they are claiming that it is the most compact and narrow in the supersport class.

[Pete Marsh]

298 points in enduro + 2.9L and 1st in fuel. (results revised - not first in fuel, but still first combined enduro fuel, and first dynamics)

Not unheard of sure, but also.....

1st accel, and 1st Autocross, giving the overall dynamics win from Monash's magic machine.

With a 210 Kg FOUR CYLINDER ENGINE!!!!! OMG!

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> UWA was able to win autocross and endurance/fuel (is it efficiency like at FSG or economy like at FS?). Some simulations tell us that a concept like RMIT or Monash should score more points in dynamics overall. Was UWA exceptionally strong of did their competitors have some bad luck? </div></BLOCKQUOTE>

It is economy like FS but for 125 points like no where else. RMIT didn't show their potential, but there were other good singles there. I guess a few people are going to have to re think their simulations. Turns out 4 cylinders can still be useful after all.

One happy Power train lead,
Pete http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Kevin Hayward]

Pete,

A single winged car did put in the quicker lap times though in both Autocross and Endurance. Also about 0.4 seconds faster on the skidpad.

I think you have not given the whole story http://fsae.com/groupee_common/emoticons/icon_smile.gif

Kev

[Big Bird]

"With a 210 Kg FOUR CYLINDER ENGINE!!!!! OMG!"

Man, those things are heavier than I realized. I thought the CBR600 engine was somewhere around the 60kg mark.

Unless of course, Pete, you resurrected one of those coal-fired jobs from back when you started in FSAE...

http://fsae.com/groupee_common/emoticons/icon_smile.gif

[Mbirt]

Congrats on the impressive powertrain development, Pete! But how much of great efficiency score can be attributed to your (and your teammate's) driving, I question... <BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kevin Hayward:
The endurance and autocross scores are also helped significantly by the most experienced driver in FSAE. Pete has won more autocrosses than probably any other driver. Even with Pete the UWA car had slower lap times than Monash. It was a lack of hit cones that meant the difference in both of the events.
</div></BLOCKQUOTE>What if you had put the same amount of effort into developing Monash's powertrain and you had also driven their car? The friction and inertia of 3 extra cylinders cannot be ignored--especially when a single has a ball/roller-bearing bottom end and at least one ball-bearing on each camshaft.

There was another car this year that won accel, won endurance, and used 2.3L fuel. ETS's thumpitty-thumper at FSAE California. They also snagged 3rd in skidpad without aerodynamic tomfoolery.

2011 has proven that a naturally aspirated single can win accel and a 4-cylinder can win fuel efficiency.


CORRECTION: Oregon State/GFR won accel with their single at FSAE West 2010.

[Pete Marsh]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> 2011 has proven that a naturally aspirated single can win accel and a 4-cylinder can win fuel efficiency.
</div></BLOCKQUOTE>

My point exactly! And yet 12 months ago it seemed everyones simulations had proved a 4 cylinder was not competitive.

@Kev - The results are down, but I think the points delta between skid and accel was about the same.I agree we were lucky Luke caught a cone in Autocross. Enduro was fuel saving, but we had nothing for Monash's fastest lap anyway. I don't want to take anything away from Monash's car, it is VERY fast, but it is not the ONLY answer as some would suggest.

I don't like the focus on my driving, it's not that relevent and is unfair to all the other drivers that are just as good, and often with far less experience than me. I think it is generally accepted you have to have at least two really good drivers to do well in FSAE, and IMO Monash brought the strongest driver line up, not UWA. They obviously have worked to get their drivers up to a high standard, and it shows in their results. It's just not true to suggest there is a significant skew in the results due to driving standards.

Pete