Engine selection: new advances V. tried and true

[jchurch]

Ok, I know some of the points I'm about to mention have been discussed in various threads in the forum, but I don't think anyone has taken this angle on it yet. I've been working with Oklahoma State's SAE team for about three years now (yes, we still have one...we just never seem to make competition.) We've always had a few members that stick with the team through each year, but this year we're incorporating it into OSU's Capstone design class. So, herein lies our problem:

We've been debating a good deal on the various engine selections that FSAE teams now have at their disposal. The experienced team members want to run with something we'll be at least slightly familiar with, while the Capstone members that haven't yet touched the project support more drastic changes to the car as a whole. For the most part, our discussion has involved the Honda F4i, the Yamaha FZ6, and (surprise) the Aprilia SXV 550.

By my judgement, our car is about due for a powerplant change since we've never deviated from the Honda powerplant. But, as always, our budget is extremely limited which by my reckoning (unless the stars align and a miracle occurs) rules out the Aprilia...So, I'm thinking the FZ6 powerplant would probably give us the most bang for our buck. We also know (vaguely) what we can expect from the FZ6 in terms of load bearing characteristics to the frame, since it's block appears similar to the layout of the F4i..

Anyone who wants to weigh in on this would be much appreciated; I know Texas A&M has been successful with both of these engines. Do any of the A&M guys have a preference, and why? I know the FZ spec yamaha engine claims to stick the powerband right where we need it due to the modified cam profile, but does it live up to its claims? Thanks in advance, everyone.

[jchurch]

Ok, I know some of the points I'm about to mention have been discussed in various threads in the forum, but I don't think anyone has taken this angle on it yet. I've been working with Oklahoma State's SAE team for about three years now (yes, we still have one...we just never seem to make competition.) We've always had a few members that stick with the team through each year, but this year we're incorporating it into OSU's Capstone design class. So, herein lies our problem:

We've been debating a good deal on the various engine selections that FSAE teams now have at their disposal. The experienced team members want to run with something we'll be at least slightly familiar with, while the Capstone members that haven't yet touched the project support more drastic changes to the car as a whole. For the most part, our discussion has involved the Honda F4i, the Yamaha FZ6, and (surprise) the Aprilia SXV 550.

By my judgement, our car is about due for a powerplant change since we've never deviated from the Honda powerplant. But, as always, our budget is extremely limited which by my reckoning (unless the stars align and a miracle occurs) rules out the Aprilia...So, I'm thinking the FZ6 powerplant would probably give us the most bang for our buck. We also know (vaguely) what we can expect from the FZ6 in terms of load bearing characteristics to the frame, since it's block appears similar to the layout of the F4i..

Anyone who wants to weigh in on this would be much appreciated; I know Texas A&M has been successful with both of these engines. Do any of the A&M guys have a preference, and why? I know the FZ spec yamaha engine claims to stick the powerband right where we need it due to the modified cam profile, but does it live up to its claims? Thanks in advance, everyone.

[drivetrainUW-Platt]

Another engine debate thread? If you knew there were ones out there why did you bother to start another one?

[jchurch]

Because the engine debate threads I've found and read don't really seem to focus on what I've mentioned here; they all have a lot of commentary and speculation on who thinks the SXV might be cool to run and why, but there's little real comparison going on...and the other threads are getting so long that they're getting off topic, so I figured a fresh start might be in order.

Also, there's little discussion on the other qualities of the engines in question; looking at the specs on the SXV, it's easy to see why it's a great FSAE engine. It's half the weight of the I-4's, and produces a comparable yet much more consistent torque curve in its stock form. I haven't yet seen anyone address anything else about the engine, like its ability to be used as a structural member in the frame.
I was just interested to see if anyone had anything to say on how the engine by itself affected the system as a whole.

[Big Bird]

Hi all,

I've been known to rattle on about engine selction till the cows come home - but won't bore you with my usual rants. I am assuming you are running the F4i currently? I might have read between the lines there.

My opinions:
FZ6 vs. F4i
To me that sounds like difference for the sake of difference. There is no real design revelation there, you are swapping one four cyl engine for another - the end results will differ so minimally it is not worthwhile. So you may be considering throwing out all your existing team knowledge in running the F4i, and starting a new development plan on an FZ6 that might one day, with time and money, get you the same results as you had with the F4i. Now I love my Yamahas, but unless you had some other motives (like having to pay for F4i's vs getting free FZ's), then I think you are just shuffling deckchairs.

Aprilia: Sounds like a great motor on paper, and I think has a lot of potential. You need to weigh that up against potential reliability issues on an unproven engine. Honestly, FSAE is won and lost on good preparation and reliability, and if you look a the results you will see that most teams are have a reliability and management problem rather than a performance problem.

If you haven't made it to comp yet, then focus on your management processes. There is no magic in the car itself - other than if you make a change of direction, it is going to distract you even more from getting the base systems in place. Any of the engines mentioned - Aprilia, an F4i, an FZ6, whatever, is capable of scoring 800 points easily and consistently. Once you have got there, that is when you can seriously start having good reasoned arguments about which one might suit your future development.

Beware of new team members. They are invariably the ones who both make the most noise about wanting changes, and have the least understanding of why you shouldn't.

Cheers all

[jchurch]

Those were exactly my sentiments on the Aprilia; but if that terrifying milky oil could be avoided by keeping an extra seal handy, then I'd definitely have a few seals on hand just in case. Waiting for parts while you're racing is never a pleasant experience.

On the switch between the 4 cyl's, we've been considering the FZ6 as opposed to the F4i 1)Because it claims to bring in its maximum torque way before the F4i
2)It's in our price range
and, 3) This is our first year to actually have enough manpower to reasonably do a full redesign on our frame/suspension setup; we've been modifying the current model VERY lightly each year since 2004 (essentially fixing known reliability issues), and we'd really like to try to expand on our current design. The way I look at it, if our frame team wants to recalculate load paths in the first place, then we may as well at least try to run an engine that gave us a better powerband location right off the bat. That's why I was trying to get some details on the FZ6, to see if it lived up to the hype on the track.

[jchurch]

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

If you haven't made it to comp yet, then focus on your management processes. There is no magic in the car itself - other than if you make a change of direction, it is going to distract you even more from getting the base systems in place. Any of the engines mentioned - Aprilia, an F4i, an FZ6, whatever, is capable of scoring 800 points easily and consistently. Once you have got there, that is when you can seriously start having good reasoned arguments about which one might suit your future development.

Beware of new team members. They are invariably the ones who both make the most noise about wanting changes, and have the least understanding of why you shouldn't.

Cheers all </div></BLOCKQUOTE>

You're exactly right in this respect, by the way. If it were left up to me, I'd love to run the F4i again simply based on the fact that it's been good to us in the past and its dirt cheap. But, in the past we've had team manager that pissed off the new guys so fast that we generally had about 3-4 that actually stuck around for the whole ride. I'm trying to make my best effort to look at every angle of an engine swap before telling them no, because I don't want it to look like my reasons are simply "cause I've been here longer and I know more than you"; that never goes over well for keeping people around...At the same time, I don't wanna compromise the project in order to keep people happy, so I'm just doing my homework as thoroughly as possible.

[Pete M]

My advice is go to comp first. I'm with big bird, your problem sounds management related. Last year you didn't end up with a car you could take to comp. This year you have more people, so you're going to be more ambitious... which might mean you're again not going to have a car you can take to comp. My point is, if you couldn't predict how much manpower it'd take you last year, why will this year be different?

If i were you i'd think about "what will get us a running car as soon as possible?" Look at what you have, and unless there is a super important reason to go in another direction, lock it in. Getting the car finished in time for a couple of months of testing and driver training will make you far far more competitive than an extra couple of Nm of torque.

If you don't believe me, look at the results and then look at what engine the teams were running. The results are so entirely jumbled up it's not funny. For example, the winners for last 3 years at FSAE Aus were: 2004 - Turbocharged CBR600F4, 2005 - NA CBR600F4i, 2006 - NA WR450 single. The other comps are similar. The engine you pick doesn't make as much difference as some people imagine (and i say this as an engine guy). What is important is that you do whatever package you decide upon well. Get it running right, get it reliable, get it comfortable to drive. And then just get it made very early. Once you're going to comp and reliably finishing the enduro, then maybe have another look at some of the basic decisions of your car.

Summary for the bored: Many teams come to comp each year with a car totally different from the last in every respect except that neither finished the enduro. It's really not the formula to win.

[benjo]

Seeing as your team is already familiar with the F4i, I would stick with it. Even if the FZ6 offers better torque down low, you could easily match that by doing some custom work on your F4i. Maybe get custom cams, better tune, better induction/exhaust etc.

[Mechanicaldan]

Being as how I've worked to make the Aprilia engines available to FSAE teams, let me speak to why or why not you should run the Aprilia.

1. First reason is money. If you don't have it, buy any 4 cylinder off E-bay. Heck, buy 3-4 so that you have spares when you blow one up or melt a piston as you learn to tune an engine.

2. Make sure you have a reliable car. If you've been to competition a few times and have a good base car that doesn't break components due to reliability problems, then go to the next step.

3. Make sure you have people that can drive a FSAE car fast. This takes a lot of practice. You need to work to get 4 team members that each have 100 hours of seat time racing your old FSAE cars. That's a good start.

4. Make sure your car isn't over 450 pounds. In my opinion, if your car doesn't weight less than 450 pounds, then you can't take advantage of the weight savings of the Aprilia engine.

5. Only at this step should you consider the Aprilia engine. It's the next logical step to having a (arguably) lighter and faster car. BUT, you need to have all the above steps accomplished first.

You can win FSAE competitons with 4 cylinder engines. You just have to know your shit and be able to drive really @#$%ing fast.

[Pete M]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Mechanicaldan:
You can win FSAE competitons with 4 cylinder engines. You just have to know your shit and be able to drive really @#$%ing fast. </div></BLOCKQUOTE>

Ok, not sure if you were trying to imply that 4 cylinder cars are at some sort of disadvantage, but if you were, i'd have to disagree. I think that, while a few teams have made a good show of singles and twins (i'm thinking of RMIT and Texas A&M particularly), the 600s are by no means obsolete as SAE powerplants. I don't think two or three comps buried in the last several years of 600 domination means much. I think it shows that you aren't necessarily uncompetitive with a single, but i don't think you can really argue much more than that yet.

[BryanH]

Pete, I am a circuit racing person so I have always thought the best measure of a racecar's worth is continous lap times and ever since RMIT rolled out their WR450 at fsae-a in 2003 they or Tex-AM have dominated Enduro lap times right up to last weekend at Silverstone. The WR450 has been an effective powerplant for RMIT because it is reliable, physically small, weighs 29kg and has a flat torque curve from 5k to 11k, number of sparkplugs have stuff all to do with it!
IMHO the Aprilla if it can be made just as reliable would be even faster.
Re engine selection, bottom line is if a Team is not prepared to design and go through the trauma of building a sub 170kg car
and impose driver height/weight limits DO NOT go for a WR450/Aprilla....but that's only me, I can't comprehend why anyone would design a car to run midfield.
Cheers
RMIT fanclub

[Pete M]

Well, as i mentioned, i thought RMIT and Texas A&M had good engine packages. I respect the direction you guys took. I just don't agree with it. And unless they radically alter their ways this year, quite a few of the other competitive teams also don't agree.

I'm mainly just trying to argue against copycat design. RMIT won the world championship last year, therefore we should run a single! Wait... but Wisconsin won this year... and they had a 600. My point was supposed to be that none of the base engines are currently dominant. Surely cornell's repeated wins with a turbo 600 count for something. And i like to think that UWA and ourselves made a decent showing at our respective last US comps (aussie bias showing a bit, I'm not as familiar with the current US field).

It's kinda arrogant to imply that everyone who doesn't build a car to your design philosophy is aiming for mid field.

[Mechanicaldan]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">the 600s are by no means obsolete as SAE powerplants. </div></BLOCKQUOTE>

Pete - I completely agree. I was not trying to say 4-cylinder engines have a disadvantage.

I was just trying to help with why a team would choose a single cylinder engine.

The 4-cylinder engines actually have a HP advantage...and they are cheaper...and are very reliable.

There are many combinations of components and people that go into winning an FSAE competition.

[adrial]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanH:
Re engine selection, bottom line is if a Team is not prepared to design and go through the trauma of building a sub 170kg car
and impose driver height/weight limits DO NOT go for a WR450/Aprilla....but that's only me, I can't comprehend why anyone would design a car to run midfield.
Cheers
RMIT fanclub </div></BLOCKQUOTE>

Impose driver height limits?

The car has to be able to fit a 95% percentile driver with proper helmet to roll hoop clearance (2" IIRC). There is no place for driver height limits beyond limiting that top 5%. How many top 5% guys do you know that are involved in FSAE?

I wish this rule was actually enforced.

[Fyhr]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by adrial:
Impose driver height limits?

The car has to be able to fit a 95% percentile driver with proper helmet to roll hoop clearance (2" IIRC). There is no place for driver height limits beyond limiting that top 5%. How many top 5% guys do you know that are involved in FSAE?

I wish this rule was actually enforced. </div></BLOCKQUOTE>

I do agree, but it needs modification, it does however seem like improvements are on the way.

Our car fits our tallest driver (194cm) with only slight problems because of his big feet that wanted to stick up over the frame right at the pedals. The "Percy" doll however wouldn't really go in at all, this basically because our seat is moulded around myself, my ass not beeing a 200mm diameter circle.

From what i heard from our faculty advisor at FS changes in this area are on their way for 2008 and 2009.

[James Waltman]

jchurch, go back and read what Big Bird and Pete M said (first post). Read them at least three times each.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanH:
I can't comprehend why anyone would design a car to run midfield.
</div></BLOCKQUOTE>

The problem is often that the struggling teams have the same attitude. They think that they have to go from 100th+ place to 1st place in one try. They aim too high and fail. In reality, they would probably score higher if they didn't get too hung up on shedding the extra pound our squeezing out the extra 1 hp.

[jchurch]

I understand exactly what they're talking about, believe me; I realize that a simple, effectively planned and reliable layout are worth far more in this competition than trying to wring an extra few hp out of your engine. In the years since I've been on the project, weight savings and power increases have been completely on the back burner in favor of fixing our known suspension issues and trying to increase overall manufacturability and reliability of our frame/susp. setup. We've just always had very limited manpower, and it's hard allocating half your machining/assembling labor to recruiting (assuming a four man team, like we have).

Regarding the quote, I wouldn't think of it as designing to run midfield; each team designs to what they feel will produce an optimum overall package. In our case, we just try to do everything we can with what we've got. I also understand that no matter how you look at it, you can't run midfield at all if you never make competition (case in point).

[Pete M]

One of the things we've noticed is that spending a lot of time recruiting never really helped us that much. Looking back on the last few years of team members, basically none of the highly committed useful people came as a result of recruiting. All the ones that ended up being very useful joined the team on their own (in some cases choosing our uni solely because of the team). I suppose it makes sense that those enthusiastic enough to find the team on their own will be those that will hang around.

I don't know if this would transfer to a team with only 4 people (we've usually got 10-20 regulars). One thing we've always noticed is that the year after we are successful, we usually get more recruits. Perhaps most of your problem is that you haven't really got anything to show them? Maybe you'd be better off not spending so much time recruiting and instead just building the car you know you need to build to make it to comp. If that means a 2 year car, maybe that's not terrible. Once you go to comp, and have some measure of success, you'll probably get a few more people curious what this FSAE thingy is.

Again, not really sure if my experience is valid for such a small team though, but it's something to think about. Is this something other teams have noticed too?

[mjdavidson]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">The problem is often that the struggling teams have the same attitude. They think that they have to go from 100th+ place to 1st place in one try. They aim too high and fail. In reality, they would probably score higher if they didn't get too hung up on shedding the extra pound our squeezing out the extra 1 hp. </div></BLOCKQUOTE>

I think you have to try to go from 100th+ to 1st place. I'm not going to be doing this for the next five years, most of us won't be. My school has no system in place to help the team succeed, there's no faculty member to help us out and no student has ever taken the time to archive information that could help future teams. I'm going to try to win it this year.

That said, I don't think engine choice is going to make or break anyone. It didn't help us out all that much(switched from a 4 to a single this year). And if you can't get to competition, you might settle for the current/functioning powertrain and work on manufacturing the rest of the car.

Starting from a blank sheet of paper I'd take the aprillia, probably. I'd have to have a SolidWorks model of it to be 100% sure.

[jchurch]

We really don't spend that much time with it; and I'm sure this comment might bring back some more people telling me that we need to spend more, etc. I should say we don't WASTE time on it; we hit it hard in the first couple weeks of the fall semester. Basically my take on it is if you're not an incoming freshman, you've probably heard about it already. Like you said, if you're interested you'll find it on your own; otherwise, we can't force people to take interest. We just try to show them how valuable the program is, (I honestly think we've got a pretty good pitch) show them what they can learn through participation, and let them make their decision. Funny you mentioned this though; I was talking to another guy that's stuck with it with me, and he mentioned that we average about one person per year that actually stays with us...so hopefully we can use the capstone program they're running this year to convince the freshman that they need to get ready early.

[JuicedH22]

I think my biggest addition to this thread would be something that has already been implied. And that is development time. It takes a good amount of time to develope and run an engine. I think trying to do a drastic engine change in one school year is insane. Is it possible, yes.. but it will take a LOT of dedication starting right now to get it to the point where the engine is reliable and competitive.

To the point of 4cyl. vs. 2 or 1. I think it is partly a matter of choice. The singles and 2's have shown they can hang, but I dont think they have shown they are dominate (with maybe the exception of fuel economy). Yes, at Formula Student, 1 and 2 were singles (3,4, and 5 were 4cyl). And at East this year, I think the top 6-7 were ALL 4 bangers. So both are good motors, it really boils down to your engine development skills, and engineering judgment. The singles and 2s have great torque bands, but the 4cyl have the horsepower advantage (and yes, HP is important, not just tq)

What I like about the 4: great HP, and if you tune it well, good tq curve as well, its also cheap, and maintainable.

What I like about the aprilla: great possibilities, but moreso... DRY SUMP

[John Stimpson]

First off, I'm totally with keeping a car designable and buildable within the manpower and money constraints imposed on the team by other factors.

That said, with enough manpower, money and driver skill, performance is all about weight. Lighten your car up as MUCH as you possibly can.

Thus, engine choice follows simply: The lightest one you can find. Which of course, is a single.

[Chris Allbee]

I'm not going to go into the performance/weight and horsepower debate. Its been done to death and I think those of use who have learned something from this competition know that there is not a universally correct answer, just local optima that occur with each design package.

That said: OSU, you haven't made it to comp in how many years? We look for you guys every time...so if you haven't competed in a while...my question is are you still building a new car every year and making amazing design strides? If you are then you are wasting time and money. Finish building a damned car and to hell with the weight, power, and whatever else. Just focus on getting to the comp this year!

[Conor]

I stick by Chris's comment. It's great that you guys are debating the engine and what not, but you mentioned you've been on the team for three years and haven't made it to competition. With all due respect, put the argument to bed and get busy building. As our team found out, you learn a lot by building for the competition, but you learn far more by being there. Good luck this season.

[John Grego]

Not to brag...but to make a point.

In 2005 we ran a 600 and easly had the fastest car but broke, in 2006 we won California with a supercharged single, and in 2007 we won California with a v-twin.

Obviously it is possible to win in SAE with any engine package. We are also well known for our engine problems (blowin up in Detroit in 2006 and the milky oil).

The thing that we have to our advantage is set up, practice time and driver talent. Our drivers are practicing year round. We've done quite a bit of driving this summer, already. We spend a lot of time setting up the car as well. Its on the scales constantly.

Just to sum up...engine is important, but as long as it runs well you can have a fast car (this is, obviously, easier said than done). Of course design judges like innovation and things that haven't been tried, but thats a whole new can of worms. Drivers, suspension design, and set up are still winning the competition. If you have the fastest car but it has a junky set up and a driver with no practice you dont stand a chance.

PS. In 2005 we showed you can have the fastest car, break, and not win. Reliability is key.

[fade]

you mentioned that you have a limited budget and a small "committed" team so i think the engine choice is pretty obvious.

[Pete M]

Lightest engine available eh? Anyone know of a good 4-stroke leaf blower engine? Its performance is way less important than its weight, right?

[John Grego]

"The engine is just a spacer. If it doesn't work get another one." -Terry Satchel during our debriefing in Detroit in 2006

[drivetrainUW-Platt]

Doesnt matter what engine you have if your tune is dick. If you spend all year developeing an engine and dont get time to tune it...might as well run a leaf blower engine.

[Dan Lentsch]

From a team that has only been around for only a year (and has a limited size), I would recommend using an engine that is not only feasible, but will keep the interest of your team. That may not be the best way to win the competition, but in my opinion it is the best way to get there. I guess that I am with everyone else who says forget having the most power / lightest weight and just build a car that will make it back. Every engine selection has its ups and downs and is arguably the best. In the end it is how well / reliable you build the car, not the engine's weight or horsepower. Last year we used a YFZ-450 because of it's low weight, and we still ended up with a car that weighed 537lbs. Granted it was our first year, but a light engine does not = a light car. This year we are using a 2007 GSXR 600 because of it's tremendous ability to generate horsepower. However, we don't have a single person on the team who has any clue to tune it let alone set it up. In other words, it's about the total package not just the engine alone.

[JuicedH22]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by John Grego:
"The engine is just a spacer. If it doesn't work get another one." -Terry Satchel during our debriefing in Detroit in 2006 </div></BLOCKQUOTE>

I agree on so many levels, with a major one being this is a suspension race, not a horsepower race... and that goes for design competition as well.

Also, I dont agree completely with the weight comment, i think once you are under 450 lbs or so, it is a case of diminishing returns... (depending on your setup) its all about your whole vehicle package.

[VFR750R]

How bout this. Buy a good 02 system, decent ECM and sensors (and a dyno if you still have money) and then buy an engine with what money you have left over. If it's a Tecumseh, at least it will run real good. Next year you should be able to afford a better engine but you'll already have the stuff you need.

[Big Bird]

Sorry jchurch, haven't had much chance to get back to respond to this one.

Funny how one of the early posts states that the engine selection topic has been done to death - and then the thread goes on to score 30-odd responses and fill a couple of pages. It is like the big red button for FSAE junkies.

The "competing to win" argument, (or trying to go from 100th to first in one year). Winning is certainly a goal we all aspire to - but more often than not the "every last bit counts" argument is used to justify some extra "design feature" that adds slabs into the development time, blows out the budget, and gives stuff-all points return. Compare the following:

Team member A: "We are playing to win, and every last bit counts - that's why we need to have a carbon fibre reinforced magnesium intake runner"

Team member B: "We are playing to win, and every last bit counts - thats why we need to have a kick-arse Cost Report"

How often do we hear the latter? Hardly ever, (probably because the guys like "B" are usually the quiet ones actually going about getting stuff done). The "B"s are the guys who are carrying your team, they are the ones that deal with all that "boring" stuff that actually makes a difference, and they are the ones you want to keep. And the "A"s are the precious little petals most likely to stuff it all up for you.

So I've got to say that if a team member doesn't want to hang around because they don't think your design decisions are "sexy" enough - they weren't worth keeping in the first place.

Cheers to John Grego for chiming in, I hope people have a good long think about the Texas A&M example. The paranoid techno junkies will dream up some convoluted argument that this proves some sort of progression that a supercharged single supercedes a four, and that a twin supercedes them both, and therefore this all justifies that we have to radically change our design. (Believe me, this happens at our uni just like anyone else). But the wise ones will see the proof an A&M's results that it all just doesn't matter a jot. Build a bloody car, drive the damn thing. And make sure that you deal with all your cost reports and stuff on the way.

I know all this project management talk gets repetitive - but look at the results year after year and you will see that the message just ain't sinking in.

Cheers all, sorry if any of that seemed blunt.

[Mechanicaldan]

FSAE has become a spec racer series.

That should be a bold enough statement to keep this post going for a couple more pages.

Here's why. The cars aren't EXACTLY the same, but they are getting pretty close. There are slight differences. Steel chassis versus carbon fiber. Inline 4 vs V-twin vs Single. 13" wheels vs 10" wheels. Yes, the suspension geometry is different, but almost every team runs unequal length upper and lower arms at each corner.

They are very similar in that they all follow the same 100+ page rule book that has been refined for at least 10 years now. They are single seaters. They all have roughly the same wheelbase and track width. The winning cars all weight less than 500 lbs and make 60-80+ hp.

New versus tried and true? I don't think it really matters. The key is IF you understand the design and can defend your choice versus other options AND provide both theoretical and physical testing evidence to reinforce your choice.

If you've been to competition, the judges will likely care more about what you've done to the engine versus which one you have. Has the crank been polished? Kniftedged? Windage tray? Head shaved? Ported? Custom pistons? Lighter connecting rods? Custom camshafts? Slipper clutch? Stock transmission ratios? Electric water pump? Dry sump oiling? Intake design? Exhaust design? 4-1? Dual 2-1? 4-2-1? ECU management? How about selectable maps for dry or wet pavement like the new GSXR1000 which has 3 different power settings? Traction control? How was the engine optimized for use with the rest of the car?

So, with a spec racing series, who wins? The team with the most knowledgable team members and fastest drivers.

Who wins an FSAE competition? The team with the most knowledgeable team members and the fastest drivers.

[flavorPacket]

Mechanicaldan, your post makes no sense. You claim this to be a spec series, and then go into several areas of diversity: powertrain, wheel size, tire size, suspension geometry, aero, etc.

For example, kansas had a 68" wheelbase. Ours was 63". Yes, they both start with a 6, but they are not even close to the same! Would you prefer a team to have a 90 inch wheelbase, and be slow as sh*t, just to be different?

do you consider Formula 1 a spec series? What about LMP1? I think you're confusing 'technically uninspiring' with 'spec series.'

It seems that you're unhappy with teams finally beginning to understand how to make a fast car. There IS an optimum design for a given track, and some teams are fairly close to finding it. And we'd all find it a lot quicker if we knew what the endurance course looked like when we were designing our cars. Just because the series is going from 90 to 95% instead of 50 to 75% of optimum doesn't mean it's a spec series.

The team with the most knowledgeable members and fastest drivers win EVERY series, not just FSAE and spec series.

[Chris Allbee]

I second A&M's comment on needing reliability. Like they mentioned you can have the fastest car and not finish endurance and watch it go out the window. Thats what happened to us in California this year. Yes, we would have been able to prevent that tactless "acceptance speech" by the Aggies if we had just had an engine that didn't explode. But thats racing. We have a great design, a great team, and our focus has been on finishing the car early and getting lots of drive time. The drive time really makes the most difference as can be seen by this example. Our car is quite a bit different from the A&M car, but either one is capable of winning. Look at any of the teams that have been in design finals or semi's in that last few years and at any given competition, they could have a chance at winning. I know that a lot of you will bitch and moan about "just because you don't get to semi's doesn't mean you can't win." This is perfectly true, but then you would have to outright smoke everyone else in the dynamic events. Good luck on that.

[drivetrainUW-Platt]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by VFR750R:
How bout this. Buy a good 02 system, decent ECM and sensors (and a dyno if you still have money) and then buy an engine with what money you have left over. If it's a Tecumseh, at least it will run real good. Next year you should be able to afford a better engine but you'll already have the stuff you need. </div></BLOCKQUOTE>

I think Tecumseh is going belly up, might want to put a Briggs, Kohler, or Honda in the 08 Cornell car instead......

[John Grego]

First, I apologize for the speech in Califonia. That was pretty much useless. Didn't thank sponsors or SAE or the other teams for coming...sorry.

moving on, in 2005 we did not make the design semis. We probably would have won the competition because our car was so fast. 1st in accell, 3rd in skidpad, 1st in auto-x, and we were up on Cornell by 25-30 seconds in enduro when we broke. It is definately possible to win without having the most innovative car. That car was very simple with a Yamaha 600, simple suspension, and steel tube chassis. But it was fast. It was ready in the middle of March and we had close to 2 months of drive time in it.

Practice makes perfect. Wasting weeks of practice to lose a few pounds is not going to help. You will be slower in the long run because your driver doesn't know the car.

[VFR750R]

Your definition of 'spec series' means every racing series including demolition derby is a spec series.

Apparently you don't understand the definition of a spec series. Spec means parts, ie chassis, engine, and/or tires are selected FOR you by the organizing body and built by a third party. This third party has a contract with the organizing body, not the teams, to provide identical parts that teams are not to modify for a resonable cost to those teams. Spec series purpose is to increase closeness of competition by defining the 'box' and restricting development and running cost.

FSAE does not pick one part we must use, they don't even limit the tire size!!

The reason we run a YZF600; it has the same frame mounts as a FZR600 which we ran since 95 or something when Nobody ran anything but a 4. That means lots of spare parts, any engine fits in any car, literally dozens of exhaust headers and intakes that are all interchangable on the dyno, testing done years ago still applies, ect ect...

It could be the shittiest engine out there, but we know so much about it and have so much invested in it, why change. Especailly considering most people agree that engines don't win the competition. I'll agree that it weighs more, but not one time that we've lost the competition has it been because of motor choice.

[Christopher Catto]

"The engine is just a spacer. If it doesn't work get another one." -Terry Satchel during our debriefing in Detroit in 2006

Seems a bit of a blunt message to give out. Ok, so any engine could win but going as far as saying that its a spacer is not wise. Also any car can win with many suspension designs, contrary to what people think.

[John Grego]

I'd think it would be hard for a MacPherson Strut or a solid axle car to win.

[prashanth]

hai,
if any one have CAD models for
Honda F4i, the Yamaha FZ6, and (surprise) the Aprilia SXV 550

please mail me to prase301@gmail.com
thanks in advance

FSAE team
IIT DELHI

[Mexellent]

Big Bird hit the nail on the head. Its all about team member B. You should run your team like a business. Set up a budget and a schedule. If you build a car that is capable of passing tech and finishing endurance, youre already way ahead of the game. The design aspect is important, but even more important is the management of team resources. Right now, youre wasting your team resources by trying to change your engine. You have F4i's and you know how to make them work. Forget about the engine and start making a part inventory. See how many parts youve got already and see how much you need to order for the new car. Make a list of all the components that arent changing, and start getting that shit out of the way. Theres a whole bunch of other shit you should be doing instead of this.

jchurch: We have been using the F4i in all our cars (with the exception of the F06 car) since 2000. Our engines are completely stock and they make more than enough power. Our F07 car weighed 475 lbs and has wings, yet the F4i had enough power to push it through acceleration fast enough for 7th place in accel, and 1st place in autocross.

[Osth]

Just to put some more gasoline on the 4v1 cyl fire: Stuttgart won FS Germany running a 4 cyl 230 kg car. It was looking amazing when I saw it at Silverstone, especially one of their endurance drivers. Must have gotten som nice settings on the car and adjusted it even further for FS Germany.

[Big Bird]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">"The engine is just a spacer. If it doesn't work get another one." -Terry Satchel during our debriefing in Detroit in 2006 </div></BLOCKQUOTE>

Sorry to bring up a reasonably old thread - but this is a great quote. Sure, I have no problem with engine-heads getting all excited about their toys - and you need those guys just like anyone else. But to the vehicle dynamicist, that is all an engine should be - a heavy spacer that acts as a force generator. Consider - your brake calipers are also lumps of material that generate a force in the opposite direction. But how often do you hear teams contemplate a change in brake calipers if their car isn't up to speed?

You need at least a couple of guys in the team that can stand back from their passions and prejudices, and make reasoned decisions based on forces, masses and costs.

Cheers all,

[flavorPacket]

Well put, but a conflict of interest soon arises when the "reasonable" guys are also the vehicle dynamics guys...

I wish that our team were large enough to warrant an experienced mamber stepping aside from a system lead role to be an unattached tech advisor.

[kmrobinson]

We liked the SXV engine but it's not the end-all be-all of FSAE engines. We're just now getting into the nitty gritty of this year's design and it'll be interesting to see what our engine guys decide upon. We might change again or even go back to something we've done before. Who knows.

[Pete M]

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

Consider - your brake calipers are also lumps of material that generate a force in the opposite direction. But how often do you hear teams contemplate a change in brake calipers if their car isn't up to speed?
</div></BLOCKQUOTE>

Ok, but our brakes are capable of locking up the wheels no matter what speed we are travelling at. Therefore, as force generating devices, they are good enough. Our engine cannot break traction at all speeds, therefore it is not "good enough". Obviously i'm not saying that the most powerful engine possible is the best, regardless of the weight, i'm just saying your analogy isn't entirely fitting.

Obviously, with power comes weight (although power can be done light, that aprilia is hardly gutless). With power often comes complexity (turbos, superchargers, variable intakes). Power also usually ends up costing more too... especially if you want it light. More power will also consume more fuel, if the power is used. So there are a hell of a lot of trade offs with power, and the light single cylinder route is definitely not stupid.

Also, comparing raw power is pointless. Power to weight ratio (of the entire car, with driver) is what makes the car go faster in a straight line. There's no point making the car 10% more powerful if you make it 10% heavier, you'll just use more fuel.

But light isn't the be all and end all either. Other than the aforementioned power to weight ratio, the only other way weight really hurts the car's performance is through the load sensitivity of the tyres. You lose some grip with a heavier car. How much depends on the tyre.

Power and weight are merely two of many parameters that affect a car's performance. Teams that focus on one to the detriment of the others are missing the boat a bit. I totally second the idea of having a couple of people on the team purely concerned with overall vehicle performance, making global decisions without pride getting in the way.

[VinceL]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> the only other way weight really hurts the car's performance is through the load sensitivity of the tyres. </div></BLOCKQUOTE>

This isn't entirely true. You're thinking in terms of steady state grip potential. But mass also has an effect on your car's transient response time. This effect is separate from grip loss due to load sensitivity.