single cylinder engines

[danzim]

Hi guys. Anyone had any experience with single cylinder engines?

Got any advice/tips about using them versus your standard 600 cc high revv-vvving 4 cyl beasts?

Which is best, KTM 520, Yamaha WR450F,
Ducati Monster, Honda CRF450F or Husqvarna 500? are there any others?

dan

[danzim]

Hi guys. Anyone had any experience with single cylinder engines?

Got any advice/tips about using them versus your standard 600 cc high revv-vvving 4 cyl beasts?

Which is best, KTM 520, Yamaha WR450F,
Ducati Monster, Honda CRF450F or Husqvarna 500? are there any others?

dan

[RickyRacer]

There is also the Cannondale 440.

Ricky

[rjwoods77]

I wonder if anyone here knows about jawa or jap motors. They are very powerfull and very light. Incredible amount of development has been done on these over many years. They run on methanol but I would assume they could be converted. They are 500 cc engine to boot. I just dont know if e-85 would cool them enough.

[Jay Fleming]

I know each of the 450s can probably be taken out to 470. Unfortunately without a restrictor, they can maybe hit 60 hp. Too bad you can't use 2 strokes. I smell a yamaha banshee engine hittin 100 hp woot.

[Ashley Denmead]

lots of teams run single cylinder engines...we run a 2004 KTM 525exc engine. very torque rich little items http://fsae.com/groupee_common/emoticons/icon_wink.gif

[jonno]

we looked at those jawa engines, quite cheap, quite agricultural, possibly a good way for a team on a budget looking at getting into the single scene. As far as i remember some run on petrol....
we looked into large displacement singles (ktm's 525 and a few 600's) but considered them too lumpy. we're happy with our choice of yam wr450.
I heard a rumour however of formula student 2006 being held at rockingham speedway, using half the track and an infield section (a bit like the indy gp) if this were the case, I'd imagine there'd be more high speed stuff playing (slightly) into the hands of the bigger BHP 4 cylinder engines....

[Bowtie Man]

The YZF 450 out of Yamaha's race quad is quite a torquy little engine, i'm not sure how the restrictor will affect it, and it probly won't be an easy one to get a hold of

[jonno]

yamaha's yfz450 quad engine is only 426cc, the wr is 450cc's. to all other intents and purposes they are the same engine. be careful you don't recommend the yz450f engine to teams though, the enduro bike version with NO ELECTRIC STARTER. i believe it is the same as the wr but with slightly advanced timing.

[Miller time]

The yfz is closer to 450cc @ 439CC, not 426cc.

[Jay Fleming]

What you can't kickstart the car? just kidding

[Denny Trimble]

I can see it now, integrated sliding pedal tray and remote kick-starter...

[MikeWaggoner at UW]

It actually wouldn't be that complex a linkage....

[drivetrainUW-Platt]

I was just reading about batteryless EFI for snowmobiles, totally eliminate the battery, throw a kick starter on a CBR 600 and we will be golden.

[danzim]

you guys that use honda CRF450 and yamaha WR450, how do you get round kick start?
did you get brand new engines?
think you could get electric start on WR450F as of 2004 and honda's latest CRX450 is electric start.

people have been saying to me that the single cyls are quite unreliable, particularly compared to the likes of CBR 600 which apparently run forever. is that true?

anyone know anything about Husqvarna engines?

has anyone got power/torque/weight data for the single cyls?



dan

[jonno]

yam wr450 has been electric start for a few years now...
the wr is on the edge of design, there are holes cut in everything to reduce the weight i'd say they are on a factor of safety of about 1.0000001, and we're anticipating making not far off stock power. the CBR is 120bhp or so stock, and there's not many teams pushing out more than 100bhp, therefore the engine isn't as stressed.
i heard our engine guy mumbling about reshimming after 10 hours running or so which also sounds abnormal and an inconvenience...
were still working out our optimal runner length by physically adjusting a telescopic runner on the dyno so we've not got power or torque curves yet, we anticipate our (initial) final map in a month or so, it'll be posted on our homepage & i'll copy it here when we've got it. Off the top of my head though i'd say 30kg, 50bhp and 50Nm but that is very speculative. We do have a supercharger for it arriving in april too........ but i really don't want to use it because
a) it's an additional complication on a wonderfully basic setup
b) i doubt the engine can deal with it even with the reinforced conrods and additional gubbins we're having made up
c) it's another headache in the general scheme of things
d) look at delft, rmit and tokyo's sprint lap times from formula student 2004 (plus remarkably Delft's acceleration time of 2nd)
1 - RMIT - 30.58
4 - Delft - 31.81
5 - Tokyo - 31.82
they all ran with a "basic" NA setup and the 450 singles got 3 of the 5 fastest times, therefore in a basic NA setup, this engine in a formula student car (certainly over the Bruntingthorpe track) appears to be able to cut it

[BryanH]

Danzim, The WR450 is a handbuilt factory race engine, not a production road bike engine, so it won't do 50000km btwn rebuilds.
Has nice stuff in it,like roller bearing crank/conrod assy. (you don't have to log oil pressure-it doesn't really have any!) It is usual to rebuild at 5000km's if raced. If the oil/filter is changed every racemeeting and only full synthetic race oil used the engine is bulletproof, can't kill it with a big stick.
Only one proviso, don't attempt internal mods! The motorcross guys who modified 450's mostly ended up with box of bits. They got YZ's if they wanted to go faster. The YZ has diff exhaust cam, stronger bottom end and approx 1000rpm higher limit.(12k) But the electric start setup cannot be retro fitted. I would advise that the WR only be rebuilt by a factory trained tech. who knows these engines, shop around.
If you get inlet/exhaust/mapping spot-on a stock engine will make 67+ hp @ 10.8k and a flat torque curve from 5.5k to 10.8k.

[danzim]

cheers halfast.
jonno, 30 kg sounds about right. is that what you got when you weighed it? did that include the carbreuttor?
if anyone's interested, the honda CRF450 is 32 kgs inc carb and a bit of oil, we weighed one the other day.

what do people think of the now discontinued, air cooled honda XR600 (42 kgs, 51.9 Nm torque at 5500 rpm). if only it wasn't kick start.

[jonno]

Danzim, that 30kg is approx i can't remember exactly what it was, i'll bang it on the scales in the morning for you to get a precise figure
I don't really like the idea of air cooled engines... whilst they are basic and increase the simplicity of things, I can't see without impressive ducting (or with the single head tilted out to one side) how you can get a good airflow behind the drivers seat. Teams do run them, so they do get them working though. any teams run an aircooled?

[danzim]

we're going for the Yamaha WR450F for NR3 as of today! how exciting! we need to get a CAD model. does anyone know where/whom i should ask. our CAD engine is autodesk inventor. don't know whether that's unusual or not. perhaps different formats can be converted? any ideas?

[jonno]

i've got a solidworks .sldasm, an ideas .mf1 and an .igs file. send an email to me00jhg@brunel.ac.uk and I'll forward the relevant one to you (i'd have thought an iges would be most likely to go into autodesk)

[Angry Joe]

Our WR426 had a kick start, we fitted some italian electric-start kit. The quality of the kit was marginal. The 450 has electric start so that shouldn't be a problem.

[Grover]

Ducati monsters are 90deg twins!! Not singles.

[MikeWaggoner at UW]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by jonno:
I don't really like the idea of air cooled engines... whilst they are basic and increase the simplicity of things, I can't see without impressive ducting (or with the single head tilted out to one side) how you can get a good airflow behind the drivers seat. Teams do run them, so they do get them working though. any teams run an aircooled? </div></BLOCKQUOTE>

Most performance "air cooled" engines are really oil cooled. They've got a wee oil cooler. It seems like you could have a more efficient system overall, since the oil can be hotter than water, and hence lose more heat.

[danzim]

so for the single cyls oil cooling is well important. i heard the bikes run the oil round the inside of the frame to dissipate the heat.

where can i found out how much heat needs losing from the oil? does the enigne have a thermostat for the oil?! would it be possible to fit one? What are the dangers of the oil being too hot or cold?
any ideas?


dan

[jonno]

The wr450 uses the frame at the front as it's oil storage, it is the portion of the frame that runs up from the lower front engine mount up to the steering pivot, a long tall column basically. either side of this in front of the bike riders knees are the two water radiators, so it's obviously where yamaha believe to be best for airflow over it.
For our install on the car we are running with the oil tank off the yzf450 quad (basically the same engine): we're intending on rejecting all heat by the water cooling system... the oil tank is partially in the airstrea though so will be cooled. It's all logged on the dyno though so any problems will instantly flag up over the next few days

[MikeWaggoner at UW]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by danzim:
so for the single cyls oil cooling is well important. i heard the bikes run the oil round the inside of the frame to dissipate the heat.

where can i found out how much heat needs losing from the oil? does the enigne have a thermostat for the oil?! would it be possible to fit one? What are the dangers of the oil being too hot or cold?
any ideas?


dan </div></BLOCKQUOTE>

Engines start with the oil cold, and unless you're doing something crazy it won't be too cold.

They make oil thermostats, I've used one for a temp gauge for air cooled VW's.

[bltsander]

about singles,

jawa engines have no transmission and make most of their power because of the methanol.

the 450s yamaha and honda, there are kits to make them 505 for AMA dirttrack racing but i know that the honda can be a 530 because the quad engine has an availible big bore kit. there is also a crank available that would make a stock motor into a 505, add this to the 530 kit and you are into the 600 range.

the honda CRF engine/trans is absolutely a terrific motor except the intake valves are hard coated Ti and as soon as you wear off the coating bye bye intake valves.

the yamaha is equally potent but i know less about them.

stay away from cannondales! i worked for a company that bought out cannondale ,,, junk...
eventhough they have fuel injection.

[Brodyj]

I have heard power ratings of singles stock over and over, but does anyone know the power of a FSAE restricted single? What does the torque curve look like?

I just don't see how the power to weight ratio of a single would be superior to a 4 banger.

[threehondas]

I make 38 HP with a 2002 Suzuki LTZ400 - I wouldn't really recomend a single, starting can be diffcult, they can kick back an blow your starter clutch, and they make way more noise than a 600/4.

Also since the 600's are designed to take 100+ HP they can the clutch and tranny/rods can take 75HP all year with no probs.

Howeve my engine was designed with 32 stock and I'm up around 40 HP now, things break/bend/wear out faster - I go through clutches all the time.

I dont know how those formula student guys ran the acceleration so fast...

Bruce
http://engsoc.queensu.ca/formulacar/engine/

[Jetser]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I dont know how those formula student guys ran the acceleration so fast... </div></BLOCKQUOTE>

acceleration isn't only about HP

[Brodyj]

What teams have been sucessfull with singles?

[Ben Inkster]

Royal Melbourne Institute of Technology (RMIT) won Student with a single.

Cheers

Ben Inkster
UWA Motorsport
University of Western Australia

[Frank]

IMO you should lose 50 points for terrible sounds whilst using a single

[Disco]

Everybody's got an opinion Frank!

RMIT produce roughly 60hp rear wheel. Not only have them won FS, but they also come second in FSAE-A 2004.

Remember, there's no right or wrong, just different!

[Igor]

Delft and Tokyo Denki were doing very well with their singles at the Formula Student event. Delft was actually first in points before a wiring problem ended the endurance.
And if Delft can do a 4.12 second acceleration with a single it's hard to argue there isn't enough power.

Igor
ps next week you can watch our new Spyker at Sebring :-)

[Ashley Denmead]

Come on guys, you all know its got nothing to do with power by itself, its a power to weight thing. you have to look at the whole package, we built a 169kg car with a 60hp single.......you do the maths. not to mention the increased drivability of a single!

ash

[Charlie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ashley Denmead: not to mention the increased drivability of a single!
</div></BLOCKQUOTE>

Maybe you should mention it, what makes it easier to drive exactly?

[Denny Trimble]

Well, if you can floor it and the car doesn't spin, that's driveability!

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

I think the lower weight (especially when coupled with other design choices) allows the tires to work better, so even with a lower power/weight ratio, a single car might be quicker. But, we'll find out about the tires in June, at least those teams that sign up for the testing will!

[Ashley Denmead]

Ok if you havnt figured out what i meant by better drivability then i'll try and explain.

im sure were all aware of the circle of traction......

a single cylinder engine has one powerstroke for every 720degrees of crank rotation, where as a 4 cyl has a powerstroke every 180 degrees of crank rotation. with this in mind a four cylinder engine puts a forward moving force into the tyre 4 times as often as a single cylinder. Due to the tyre not being worked as often to produce forward motion there is more lateral grip available for cornering.

hope this explains what the heck i was on about earlier.

Another argument for singles is that some people believe they are more forgiving on driver error as they dont penalize the driver as much if the wrong gear is selected due to their low down torque and pulling power as compared to a high revving 4 cylinder 'Power engines'.

Anyway compromise is the name of the game......Just build the damn car and worry about making it go fast later http://fsae.com/groupee_common/emoticons/icon_wink.gif haha

cheers

ash

[Kevin Hayward]

Ash,

Excuse my ignorance but ...

I am having difficulty seeing how lowering the longitudinal loading frequency and increasing its amplitude increases lateral tyre loading capability.

Unforunately my knowledge of tyre frequency behaviour is pretty minimal. Did you pick this up from a reference or testing or is it more of a reasoned explanation?

I have heard a similar explanation from other people running singles and I am getting more and more curious as to where this theory cam from.

Kev

UWA Motorsport

[Denny Trimble]

I remember reading in a motorcycle magazine a long time ago that one of the top race teams was investigating an odd firing order, to get most of the power pulses closer together, and to leave a longer period of no power. I guess the theory was that the tire could recover from the power pulse if it had enough time, but that four evenly spaced pulses wouldn't allow the tire to recover.

I'd seriously doubt this without seeing any data. Wouldn't you need a dynamic model of the entire powertrain, plus tire frequency data as Kevin mentioned?

About the torque curve and gear selection, we tune our engine to be driven from 6000 to 12000 rpm on course. There is enough gear overlap that some of our fastest drivers choose different gears on certain sections of each course. So, that's not the territory of singles only.

[Charlie]

I also have serious doubts about that Ashley, but wouldn't dismiss it entirely. I'd also like to see where you got that from and/or if you have other support for the theory.

Like Kevin (and a whole lot of other people I'm sure) I'm not too familiar with how tires dampen and respond to frequencies, but my instinct tells me that pulsing the tire harder but less frequently would result in worse tire dynamics. Seems to me that you would look at the peak of longitudinal loading to determine how much capability the tire has. Unless your driver can correct every pulse to get the most out of the tire http://fsae.com/groupee_common/emoticons/icon_wink.gif I don't quite buy it. But that's my opinion without much to back it up.

Like Denny I'd compare our torque curve to a single's anyday.

[Frank]

(taking another dig)

i'd rather listen to, god forbid, rotary's than singles

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

[rjwoods77]

I read a neat article back in the day about engine transient response. The editior was talking of how a motor with less overall power output can be quicker in a race than one with more power and less response. I always had a contention, after seeing fsae cars in person and in videos that the engines spend a lot of time getting to the power band than actually driving on it. That combined with the weight/power, I think is where some of the true on track speeds of these cars is can really be derived from. This is obvious to some of the senior guys on the site here but I felt it was worth mentioning to the discussion if people werent thinking it.

After re-reading that article. I wonder how many teams out there "recalibrate" a tach for sound testing. I guess it doesnt matter anyway because I hear all about how a lot of top teams cars get a lot louder on the track than they were at sound testing. Different maps? Conditioning tach signal? http://fsae.com/groupee_common/emoticons/icon_smile.gif

Hey Frank,
I was at a vintage car race once. That had a bunch of group whatever prototype cars. Stuff like lola-judd and such. The kudzu-mazdas sounding like sticky ass sweat when they got off throttle in braking zones. Sounding like they were just breaking into little pieces.

http://www.theoldone.com/archive/world-according1whatishp.htm

[Dan G]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I wonder how many teams out there "recalibrate" a tach for sound testing. </div></BLOCKQUOTE>

never heard of anyone doing that
***cough, cough***

The fancier tachs have "divider" options. Makes meeting sound regs a lot easier.

But I've never seen/heard of anyone doing that
***cough, cough***

[GTmule]

the Kudzu's are all either 2 or 3 rotors (usually turbo, always with the 2 Rotors). They sound terrible.

but a 4 rotor sounds GREAT, IMO.

not ferarri V12, merlin or Gt-40/Cobra 427 great, but great.

[Z]

Here's the story about the "big bang" theory of tyre grip, as I heard it.

The team was Honda GP500 (they were quite succesful).

The engineers got some riders to test two bikes. The bikes were identical except for their engines. After some laps on each bike all the riders gave pretty much the same report - "One bike screams and the other bike makes a droning sound. The droner vibrates more and it has less power".

The engineers checked their time sheets and scratched their heads. The riders were of varying ability so their times varied a bit, but each rider's time on the droner was about two seconds faster than on the screamer!

The engineers knew that the droner would vibrate more. The engines were 2-stroke V4s. The screamer had power pulses on 0/90/180/270/360 (ie. even), and was reasonably well balanced dynamically. The droner had power pulses on 0/45/90/135/.../360 etc., (ie. a bit like a big single), and was less well balanced. But on the dyno both engines gave the same power.

The time sheets (or data logging?) showed that both bikes had the same top speed, but the droner was faster through corners. Because of the faster exit speed the riders on the droner were reaching top speed earlier in the straight, whereas the screamer would keep accelerating further down the straight. Hence the misconception that the screamer had more power. So far (supposedly) this was all measurable fact. Now for the conjecture.

As the rider on the screamer opened the throttles at mid-corner the rear tyre would approach its peak force and then exceed it. Once over the peak the engine would increase speed (less resistance), the tyre would slide more, and the rider would have to quickly back off the throttles. However, the droner acted a bit like a pulse-width modulated power supply. The rear tyre would repeatedly pass its peak, but just as quickly come back to the "safe side"
of the hill. This rounded off the droner's tyre force hill, compared with the much sharper peak of the screamer.

The screamer could probably sustain a higher peak force than the droner, but no rider could get to the top of that peak and stay there. The droner had a gentler hill, possibly lower, but the riders could easily stay at the top of it.

Well that's the argument as I heard it. Sounds reasonable? Could work in FSAE? Would possibly work better with a 600cc thumper than a 400cc screamer (both singles)? Or with a supercharged 600cc single redlining (or choking) at 6000rpm (no need for gears)?

[Big Bird]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Frank:
(taking another dig)

i'd rather listen to, god forbid, rotary's than singles

http://fsae.com/groupee_common/emoticons/icon_smile.gif </div></BLOCKQUOTE>

I'd rather listen to Rotor than you, Frank....

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

[Big Bird]

As for the tyre "peaking" and then "recovering" debate, it is probably a point of idle conjecture. I don't necessarily believe that we here on this forum would have access to the right answer on that front, but one thing i would say is beware of slick salesman talk.

The Honda 500 GP scenario revolved around Mick Doohan, who was not only a damn good rider, but with the help of his Chief Engineer Jerry Burgess (?? memory ??) was a master tactician as well. Honda was supplying NSR500's to a number of top GP teams during the 90's, with Mick being the centre of HRC's development focus (with a supposed trickle-down to the other teams). At the start of 1995 (I think it was), everyone in the paddock noticed that the bike HRC wheeled out for Doohan for pre-season testing had a really flat sound - the droner. No-one else had one. Mick won lots of races that year, and suddenly all the other Honda teams were moaning that they were being fed second rate stuff. Championship to Mick and Jerry , dummy spits from the other riders.

Mick continued to win races on the droner over the next few years, with a few of these bikes filtering down to other teams - with little effect. All the while there were odd theories being bandied around, initially as to why the droner was so good (tyre peaking / recovering), and then later to why it suited Mick better than the other riders (Mick's dirt track background as opposed to the junior asphalt classes of most of his opponents, blah blah blah). More Doohan championships, more head scratching and soul searching in the other pit garages - some because they couldn't get a droner, others because they had droners and still couldn't win.

When it got to the point that most of their rivals had droners - Mick and Jerry got HRC to build them a screamer again. Suddenly Mick's bike sounded different again, and because he was still beating everyone the tables turned. The screamer apparently better suited Mick's developing riding style, suited the tyres of the time better, enabled him to slide easier - due of course to the contact patch not being able to recover between pulses.....

After Mick retired, he said that he couldn't have given a flying fish whether he was riding a screamer or a droner, they were just as fast. It was all just a bit of a mind game they were playing on the other riders. Touche.

Moral? Probably don't sweat over things that we have no way of knowing an answer. Fun to think about, but ultimately time-wasting. And also note that these were mind games being played where hundredths of a second make a big difference - we have a long way to go with driver consistency and reliability before our comp gets anything like that.

I could carp on for hours about the relative merits of singles and multis - and I have previously. And I'm sure if dyno charts of various singles were put up here, I'm sure any number of teams could argue that their engines are "better". I guess it depends under what criteria you choose an engine. It seems that some (most?) teams only choose/develop their engines relating to how they can maximize longitudinal acceleration - which is effective on, what, 15% of a typical Enduro/AutoX track?? We spent more time thinking about what all that engine size and weight was doing the other 85% of the time, (and if you think hard you'll realize that is not measured by the oft-quoted powerto weight ratio - more like braking power to weight ratio, cornering power to weight ratio....).

And did i mention the fuel economy event......

I'd been sort of hoping that with a few singles starting to do well, people would start thinking about their engine choices a little more laterally than just how they push the car forward. But engine-heads will be engine-heads....

Cheers all

[BryanH]

"big bang" isn't a theory but fact of life for MotoGP teams, attempting to put 250+ bhp through one tyre.
Vale Rossi tested the 360 and 180 deg engine early 2004 and even though the 1st Yamaha Big Bang in-line 4 was down on power it made faster lap times. Yamaha did find the HP and Vale won the world title!
One point missed in "Z"'s excell. post is that the instant. torque peak at the tyre is doubled in the 360deg engine.
And given that torque is almost entirely a function of swept volume a 450cc single has 3 times the instant. torque peak of a 600/4, much less rotating inertia and 540 deg crank rotation for the contact patch to recover.
Yes, 5 valves versus 16+ means less peak power, but power to weight for a good single is 6lb/hp.

In the 1960's Stan Wallis in Adelaide built a "Big Bang" inline 6cyl for speedcar racing. I saw it in pieces so can't tell Frank how fast it was/crappy it sounded.
When I raced karts (remember the good old days Pat?) I noticed that the guys running twins spent a lot of time syncro-ing the engines to fire at exactly the same time. They said that any other setting was slower.
If the suprisingly ignorant senior citizens of this forum want tyre data, find info on why ABS brake systems are calibrated to do what they do.(to the tyre contact patch)

[Big Bird]

Oh Halfast, what did you go and do that for. I'd only had one minute of glory and you've shot me down in flames already. Hey, it is the middle of the day. Haven't you gots lawns to mow or something?? http://fsae.com/groupee_common/emoticons/icon_smile.gif

Cheers old stick

[BryanH]

Sorry buddy, I was crapping on at the same time you were putting yours together! I'm watching the 1st round of the world superbike champs. If I am not very much mistaken 1/2 the field sound like big bang engines!
Last week at the GP while not perving, was saying to Rotor that some sort of ready to run engine package would be a huge help to many fsae teams, allowing them to concentrate on designing, building, testing a car, instead of spending huge amounts of their time just getting the thing running/tuned/staying together.
There was a Briggs&Strat 300cc drag engine on display. Owner quoted 34bhp @8,500 (but only for 12 sec) and a cost of A$15000!
But Frank, it sounded like a top fuel car at idle.

[Ashley Denmead]

Crikey, this thread has taken off since i was last logged in......Thanks to all especially Geoff, halfast and z (whoever you are) who replied and probably explained the theory better than i could have anyway! and to the data question earlier.....No i have no data to support my claims on the tyre pulsing debate but i do know that i have seen how the power is put to the ground in our single cyl (most obvious during wheel spin at launch) with my own eyes and the theory certainly makes some sense to me but i do agree with geoff that the benefit is probably insignificant in the competition but then again each decision has to be backed up so hey the big bang theory for lateral accelaration is one extra tick in the box.

Ash

[PatClarke]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">When I raced karts (remember the good old days Pat?) </div></BLOCKQUOTE>
Haha, I have to make one of my rare responses here =]
When I raced twin engined karts, I tested them with both engines firing together, 180 degrees apart, 90 degrees apart 45 degrees apart etc etc.
The method I finally settled on was this...
When I bolted the engines on the chassis, I simply put the chains on! Where the engines were relative to each other seemed to make no real difference apart from moving the vibration band to a different RPM.
What hurt the rear tyres on those karts (And boy, did we hurt the tyres!) was more to do with the lousy weight distribution we were forced to use and the 'band aid' chassis solutions employed to overcome understeer!
But you are right about the 'good old days' we sure had fun!
Pat

[Big Bird]

[QUOTE]Originally posted by Halfast:

Last week at the GP while not perving, was saying to Rotor that some sort of ready to run engine package would be a huge help to many fsae teams, allowing them to concentrate on designing, building, testing a car, instead of spending huge amounts of their time just getting the thing running/tuned/staying together.
QUOTE]

Agreed completely there Mr. Halfast. Would save a lot of headaches for many teams. I know that many would argue that such an arrangement would remove part of the learning outcome of the project, specifically for those who want to learn engine theory. But by removing a lot of unnecessary complication you might see more teams making it to the finish line (or in a lot of cases, to the start line....).

Might also lessen such oddities as when a team (such as one dear to us both) loses points in Design because it's engine package is "not complex enough". (Given that I see good design as achieving an end with minimal complexity, maybe we can take that as a begrudging compliment http://fsae.com/groupee_common/emoticons/icon_smile.gif ).

And just in case I seemed a bit dismissive in the whole tyre response debate above. It is something that interests me greatly, and I've spent more than a bit of time wondering about it over the years. I was more commenting that the effect wouldn't be as pronounced given our amateur drivers and the higher emphasis on just getting the project completed rather than outright vehicle performance.

Cheers all

[Z]

The latest (April 05) issue of Race Engine Technology (Ian Bamsey's sister mag. to RaceTech) has an article by Gordon Blair & Assoc. on big-bang MotoGP engines. Its more to do with intake pulsing in the airbox effecting engine power than with rear tyre grip.

The bottom line is that you just have to buy his Virtual Engine software if you want to be competitive...

[little miss bossy]

It wouldn't be a single cylinder thread without Big Bird's contributions http://fsae.com/groupee_common/emoticons/icon_razz.gif

Oh, and Frank... roll your sleeves up http://fsae.com/groupee_common/emoticons/icon_wink.gif

[jonno]

I mentioned a while ago on this thread that I'd post how heavy the singles are

2004 Yamaha WR450 - 29kg

[Shiraz]

hey guys, i dont think i agree with your engine package ideas! In my humble opinion FSAE is what it is cause it needs a team to be one and integrate subsystems/designs/personalities to have any significant impact.
The option of an engine package in my eyes takes alot of the integration away. I do understand where your comming from, but maybe if its so hard to get right we should have standard suspension packages too!! If it was a racing series it would be a great idea, the last time i checked it was all about an engineering exercise.

Cheers

[threehondas]

It seems that an ebay purchased F4i with stock injectors and Motec or PE Controller with a junkyard throttle, average diffuser section, ~3L intake and long runners practically is and engine package capable of 60+hp, 70+ if you get it right!

[Mechanicaldan]

In my opinion, that's why so many teams run inline four bike engines Bruce. It's cheap and easy. There is SO MUCH to learn. It's taken our team 4 years to get a very good racecar. In that time, the engine has remained a Kawasaki ZX-6R, and it's always made around 60 HP. We've tried to concentrate on the torque curve and gearing, to make the car easy to drive. The suspension and brakes have evolved every year, and last year's car weighted 450 lbs. All that was missing was fuel. We placed 13th in acceleration. Both drivers had equal times, and one had never driven the car. Our autocross and skidpad scores were poor because we had not driven the car.

Singles can be competitive, but the car has to weigh around 300 lbs. The big pictures is that a single cylinder powered car is much harder to build correctly and competitively. As we all know, just finishing the car is hard enough.

[Big Bird]

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

Singles can be competitive, but the car has to weigh around 300 lbs. The big pictures is that a single cylinder powered car is much harder to build correctly and competitively. As we all know, just finishing the car is hard enough. </div></BLOCKQUOTE>

Hmmm. Sounds like you've got the blinkers on there Daniniowa. 300lbs? Would you like to explain where you have plucked this figure from? The RMIT FStudent winner weighed around 430lbs. Quite porky by your standards. The 2004 car (second outright FSAE-A) weighed in around 400lbs. As for competition, the car placed between Wollongong and UWA, so you can't argue about lack of competition.

A 4 is simpler? Would you like to explain how it is simpler to design an intake to feed four cylinders than it is to feed one? Would you like to show me an exhaust for a 4 that was built from scratch in half an hour?

I don't know what you are basing your generalizations on, but having been there and done that I'll say here and now that it is not difficult to build one of these things correctly and competitively. You won't get me to say that a single is outright better than a multi, but you'll certainly get an argument from me if you want to just dismiss them outright.

Cheers all,

[The guru of guru's]

OK time to put an end to this thread.
Singles are better....

Dont believe me????
try it for yourself...i dare you!!!

[Ashley Denmead]

hahahahahaha

No dave your wrong mate.....singles suck....nobody should use them RIGHT!!!

speaking of low mass and low PMI geoff.....how bout that deakin car!!!

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

[The guru of guru's]

Once again you are right....Thats it the gloves are off!!!! F@#K singles... lets go back to the good old turbo ninja crap!!! http://fsae.com/groupee_common/emoticons/icon_wink.gif http://fsae.com/groupee_common/emoticons/icon_wink.gif

[Mechanicaldan]

First off, you shouldn't be starting an arguement, as there is nothing in my post about "dismissing them outright."

Maybe you should reread what I posted. "The big picture is that a single cylinder powered car is much harder to build correctly and competitively." As you pointed out, 1 win for a single. How many for inline fours?

I think I did the math here:
http://fsae.com/eve/forums/a/tpc/f/125607348/m/4006096252/p/1

I never said a 4 was simpler. I said cheaper and easier, to which I will firmly hold my ground. First point is that inline-4 engines are much easier to source. Check E-bay for proof.

My generalizations are based on my observations of going to Pontiac and seeing 98% of the cars powered by inline-4s. Seems to me that in the big picture it is "simpler."

Here's something that is good to start an arguement with:

Teams should focus more on finishing a car early to test it, fix any problems, and learn to drive it well. They should only spend enough time engineering and manufacturing it to get to a driveable car by a Spring Break deadline.

Want to know another truth? Teams that have an established competitive car do just this.

RMIT won for the same reasons all other teams have one. The entire car and team pachage was organized and executed well. Congratulations.

[jonno]

Daninowa, cheaper, maybe, easier no way.

1) the unit is much smaller making packaging infinately better and easier

2) there is only 1 inlet saving space and providing easier access to everything

3) there is subsequently only 1 injector required, unless you want to get extravagent and have multi-stage injection therefore easier to map

4) there is only one exhaust which as Geoff pointed out can be therefore made in house in half an hour. That's a lot easier than getting four pipes bent then welded.

5) there is only one coil to take care of so again 75% less wiring there which sounds easier

your generalisations are based on going to Pontiac and seeing 98% of teams "doing the same thing engine-wise" year in year out. Whilst sticking with what you have may be simpler, a new team starting out or a team wishing to change from an old engine I doubt would find setting up a 4 cylinder engine "easier" than setting up a single for at least the 5 reasons listed above.

Your maths is also flawed:

Stock inline 4 makes 100 hp.
Stock single makes 60 hp.
Restrictor takes away 25% power.

This is true with the 4's but not so with the singles. Our 2004 CBR600 had around 70bhp and was set up for torque. Our 2005 WR450 has broader and higher torque (sorry don't have the figures to hand) and we are looking at getting around 60bhp. Therefore the power is down slightly on the 4 but is not really changed from standard. Data from the Formula Student track shows you are at WOT for around 15% of the lap. So 85% of the time your extra 10 or so horsepower is wasted. I will provisionally agree then that for the 15% of the time at WOT a four has the advantage... or does it? Delft came 2nd in acceleration at Formula Student with the yamaha wr450.
As just mentioned for 85% of a lap we are not at wide open throttle, we are going round cones and corners, and here is where power to weight is meaningless, it is all about low weight and a well set up car dynamically. Assuming we stuck our new engine in our 2004 car BR5 which weighed 227kg wet. Take the 70kg cbr out and replace it with the 29kg wr450 (this doesn't account for saving 3/4 of the exhaust, intake and wiring loom and less fuel and oil required). The car now weighs 186kg. the power to weight of BR-5 at 227kg was 308 bhp/tonne. if we swapped the engine and assume the 60bhp we get 322 bhp/tonne. Therefore a marginally better power to weight ratio is achieved with a straight swap. That is only the beginning of the saves though. The engine does make less power, so all drive components can be downsized - saving more weight. Since the car is generally lighter many other components all over the car can be downsized - further improving that weight figure. As Geoff pointed out, the RMIT formula student car was heavy, their second single was lighter, you say they won through being "well organised and executed well". This may be the case, but there were other well organised theams out there. The difference is that organising a simple package is much easier, there are less things to think about, bringing us back to the point about singles generally being easier. Imagine the following scenario... a well established proven wining car (RMIT) have entered formula student again for 2005 where they are going to be against many proven four teams, but as far as i know so far at least 4 of the 59 registered teams will be running a single (RMIT, delft UCLan and Brunel). Loughborough are heading the simpler route in '06 and many many teams I spoke with at Autosport are intending to run the singles in 2006 for the simplicity.

So Daninowa I put this point to you: a field of established competitive singles (say 160kg, 340bhp/tonne) vs a field of established competitive 4's (say 190kg 360bhp / tonne). What would the outcome be?

[Igor]

Before any of the four-is-more crowd jump on it;
The drive components have to be upsized for a single instead of downsized. I agree with the rest of the argument though.
I think it is also telling that very few to none of the single-cylinder teams is thinking about ever going back to 4 cylinders....

But it'll probably take some more good single cylinder cars for a paradigm shift, especially in the US where Cornell keeps winning :-)

Igor

[jonno]

Igor,
how come you had to upsize? Our numbers aren't entirely realistic there cos the Quaife kit we had with the CBR was oversized and we've been real precise speccing up the drive with our WR...

[syoung]

I understand that the endurance & sprint circuits in FSAE and FSAE-A are quicker than their FS equivalent - anybody able to confirm or refute this?

Personally I'd definitely go for a single-cylinder engine if I was starting up a brand new team for an FS competition on the Bruntingthorpe kart track. Well, if I could afford it anyway. Whether I'd do the same for a noticeably faster venue is a much trickier question.

[VFR750R]

I realize this post is about singles, but it is also about their decreased weight. I'm not a chassis guy but i like to start fires so here it goes.

Is it possible that by decreasing the weight of the car you are increasing the ratio of unsprung to sprung weight which has a bad effect on suspension dynamics. And could it also be possible, since we already below the point where tire forces are linear, that a lower weight car is further from this point and perhaps not loading the tires enough? Do other chassis forces such as stiction in the rod ends, rockers, shock shafts ect. now become a greater percentage of the forces acting on the suspension and that also decrease the responsiveness of the car. Although a lighter car would eventually be better off with mountain bike shocks then midget shocks?

Maybe I'm spltting hairs here but maybe that's racing.

[Eddie Martin]

There are lots of positives and negatives to both 4 cylinders and singles, it depends on what suits the car you want to design and what suits the team/uni.
It may also depend on which competition you are entering. Each competition has a different "style" of track layout, you really have to design the car for that course.

Also when you are doing power to weight calculations you really should include the driver's mass as the car has to run with a driver. http://fsae.com/groupee_common/emoticons/icon_smile.gif The numbers do change a bit with that. ( A CBR F4 weighs about 58 kg. from memory).

[Jarrod]

Simon,
The current FSAE-A track at werribee is no faster than the bruntingthorpe track, it was actually very similar in terms of the proportion of tight chicanes, slaloms, i think a couple of the corners at bruntingthorpe were probably a little quicker. I can't comment on detroit but it looks tight on some of the videos.

[Igor]

Jonathan,

With a single cylinder you get one huge torque pulse per revolution where a four cylinder has four smaller ones.

Igor

[Skooter327]

With regards to the tire pulse discussion:
Kevin Cameron wrote an excellent column on this subject (including Big Bang MotoGP engines) in the November 2004 issue of Cycle World. By some of the posts in this thread, I suspect several of you have read it.

I've heard the same theory applied to motorcycle dirt track racing to explain an advantage the Harly XR-750s enjoyed over the British and Yamaha parallel twins.

[Cement Legs]

We are adopting singles this year... We are using 330 1.8 cc RC car engines mounted in series.

1/Teq = 1/T1+1/T2+...+1/T330

We just have to figure out how to get the nitrous past the scrutineers http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[MikeWaggoner at UW]

"The drive components have to be upsized for a single instead of downsized."-Igor

You're going to see enough torque in either car to break the tires loose. Therefore, the design has to be able to hold tire torque, not engine power. The torque will go down with smaller tires, which many single teams use.

I've also seen people murmur that the gearbox isn't strong enough in the single, but I haven't seen any gearbox mods done to the singles, and I'd think designing for the shock loads you see in offroading (driver floors it in air, gets everything going fast, impact loads etc) would be similar to those you see in a street bike.

[Z]

This thread is too good to fall out the bottom.

So, just say your team has got the chassis well sorted and they want a good single (they're smart), and you've got enough resources to build your own engine. What sort of single would you build?

Just to get the ball rolling:
* 4" bore piston/rings/pin/conrod/bearings from "small block V8" supplier (good quality at reasonable prices).
* Bespoke crank with 75 mm stroke for 608cc.
* 2 valve head (also V8 parts) with EFI etc.
* Billet alum. block, head, etc.
* Primary balance shafts on bottom of block.
* Now the secret weapon - 120cc combustion chamber volume giving 6:1 CR!
* Screw type S/C feeding 1500cc per 2 revs for effective CR =~12.5:1.

This should pull like a 1500cc engine at low revs, choke at maybe 5000rpm, and maybe still make some power at 6k. The low expansion ratio means poor thermal and fuel efficiency and hot exhaust (fit a turbo next year). But the main advantage is that it might not need any gearbox, just a big clutch and neutral, and heavy duty chain and drive shafts. Should also be compact, light, and very easy to drive.

What do you reckon???

Z

[Matt N]

Hey Z-

Freaky, I have been discussing an idea that is 90% identical to what you listed above...

Course, I've got an even worse (more radical) idea than that for a one-off engine too.

Matthew

[Z]

Sharing is good for the soul...

Could also use head from dirt bike with 100mm bore (Yamaha, Husaberg,...)???

Z

[Daves]

After pondering what kind of ideal autocross car I would like to own, I considered a single cylinder FSAE-type car. Most likely I would drive it a maximum of once per month and tow it on a trailer behind a Honda Civic. I would shy away from a 4-cylinder 600cc engine because working on it by myself would be difficult and expensive. It would weigh nearly 500 pounds and have an engine that weighs 140 pounds. I don't think I'd want an autocross-only vehicle that weighs more than 400 lb.

[VFR750R]

That's great Dave, if the car weighed 400 or 500lbs, you still can't lift it by yourself, but the 500lb car would then make crap loads more power cause for autocrossing...no restrictor. Hmmm....500lbs, and 140hp. Goodby go-kart.

Either would be fun...but I'm an engine guy, i NEED it.

[threehondas]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dave @ L.U.:
After pondering what kind of ideal autocross car I would like to own, I considered a single cylinder FSAE-type car. Most likely I would drive it a maximum of once per month and tow it on a trailer behind a Honda Civic. I would shy away from a 4-cylinder 600cc engine because working on it by myself would be difficult and expensive. It would weigh nearly 500 pounds and have an engine that weighs 140 pounds. I don't think I'd want an autocross-only vehicle that weighs more than 400 lb. </div></BLOCKQUOTE>

Maintenance on a single vs four banger:

Both need oil changes at similar intevals
Both never need timing set
Both have one cam chain
Singles with roller bearing cranks are harder to strip down to the cases. Well perhaps not harder just different. Everything gets pressed/pulled in and out with special tools that you can make on a lathe and mill.
If you need new rings odds are the bearings, cam chain + tensioners are going too... its almost cheaper to buy a whole 'newer' engine off ebay. A low mileage F4i just went for 400 bucks last week.

The only difference would be valve setting... 16 vs 4. Yeah the singe wins there - But your driving once a month? So your valves should be set hmmm.... like once every three years then? Honda valves dont seem to move around vary much (depends on how much you love your rev limiter too). I've run honda motorcycles as far as 40,000km with track days and then finally one valve needed to be set 'cause it was out 1 thou. However sometime they move around more on the CBR. Someone else want to comment on their CBR valve adjustments?

Singles only barely surpass the CBR on service time unless your talking about valve clearance. I still find the CBR friendlier to work on but thats just me. I like the horizontally split case. Its more forgiving than using a press for the super tight fits on the roller bearing cased singles.

I dont want to even go into taking singles vs fours for engine removal. Thats a can of worms and has no "right answer".

Bruce

[VFR750R]

Totally forgot. CRF450 valve maintainance schedule...5hrs
YZF600.....20,000miles

[BryanP]

My high school Technological design class has been attempting to enter the FSAE competition for the past three years. I have always felt this competition is great and have incorporated the challenge into my course. Our goal is to become the first high school team entered. So far no luck. Our current car uses a Yamaha Raptor 660R single motor ( from the atv)mounted longitudinally. The motor has great torque and is bulletproof. ( we hope). I am curious as to why this motor has not appeared in any FSAE car. Check out the tech specs on the motor. seems like a good choice to me. As well we have designed and built all the usual stuff such as independent suspension, limited slip rear differential,etc.We are located in Aurora, Ontario Canada and would love to get a chance to drive with some of the FSAE teams. I know that we have a 660 engine but if we were accepted to the competition we would be glad to de stroke the motor. I would also be happy to post some photos to show what high school students can do.

[Garlic]

You wonder why nobody uses the engine? How about it's not legal!!! Destroking or sleeving an engine isn't out of the realm of possibility, but it's not simple or cheap either.

Anyway good luck on your team's quest, wish I did that in HS.

[Didier Beaudoin]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanP:
My high school Technological design class has been attempting to enter the FSAE competition for the past three years. I have always felt this competition is great and have incorporated the challenge into my course. Our goal is to become the first high school team entered. So far no luck. Our current car uses a Yamaha Raptor 660R single motor ( from the atv)mounted longitudinally. The motor has great torque and is bulletproof. ( we hope). I am curious as to why this motor has not appeared in any FSAE car. Check out the tech specs on the motor. seems like a good choice to me. As well we have designed and built all the usual stuff such as independent suspension, limited slip rear differential,etc.We are located in Aurora, Ontario Canada and would love to get a chance to drive with some of the FSAE teams. I know that we have a 660 engine but if we were accepted to the competition we would be glad to de stroke the motor. I would also be happy to post some photos to show what high school students can do. </div></BLOCKQUOTE>

You wouldn't be the first pre-universitary school to compete though, I was captain of the École nationale d'aérotechnique team that competed last year. http://fsae.com/groupee_common/emoticons/icon_wink.gif It's a technical school, we call it CEGEP here in Quebec...

Anyways, good luck, but you should look into your engine, the limit is 610cc...

[BryanP]

Actually there is a sleeve and piston from the sister engine (Grizzly) that will fit in quite nicely. It gives a displacement of 595 cc.I have an estimate from a reputable engine builder of $500 cdn. if we disassemble the engine. That is expensive but not the price of the turbo systems that some of the teams run. We wanted to use a single to keep the car small and light.( 60 inch wheelbase) The problem that we anticipated with some of the 400 or 450 dirt bike or quad engines is they are highly stressed and blow up too often for our budget. The Raptor is very reliable. .You can see from the attached photo that we were able to mount it to a Honda 450 Es differential by turning a hub and wire edm ing it to fit the output spline on the engine. Oops. I am having problems attaching the photo. I will repost it as soon as I get it sorted out
Thaks for the interest<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Garlic:
You wonder why nobody uses the engine? How about it's not legal!!! Destroking or sleeving an engine isn't out of the realm of possibility, but it's not simple or cheap either.

Anyway good luck on your team's quest, wish I did that in HS. </div></BLOCKQUOTE>

[BryanP]

I have just posted three photos of the car on the forum. I will add more soon. I checked out the École nationale d'aérotechnique website. That is an awesome school. I wish we had facilities like that.
Bryan<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Didier Beaudoin:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanP:
My high school Technological design class has been attempting to enter the FSAE competition for the past three years. I have always felt this competition is great and have incorporated the challenge into my course. Our goal is to become the first high school team entered. So far no luck. Our current car uses a Yamaha Raptor 660R single motor ( from the atv)mounted longitudinally. The motor has great torque and is bulletproof. ( we hope). I am curious as to why this motor has not appeared in any FSAE car. Check out the tech specs on the motor. seems like a good choice to me. As well we have designed and built all the usual stuff such as independent suspension, limited slip rear differential,etc.We are located in Aurora, Ontario Canada and would love to get a chance to drive with some of the FSAE teams. I know that we have a 660 engine but if we were accepted to the competition we would be glad to de stroke the motor. I would also be happy to post some photos to show what high school students can do. </div></BLOCKQUOTE>

You wouldn't be the first pre-universitary school to compete though, I was captain of the École nationale d'aérotechnique team that competed last year. http://fsae.com/groupee_common/emoticons/icon_wink.gif It's a technical school, we call it CEGEP here in Quebec...

Anyways, good luck, but you should look into your engine, the limit is 610cc... </div></BLOCKQUOTE>

[Z]

Bryan,

I think the Yamaha Raptor/Grizzly engines, or similar ~600cc singles, are very good choices for FSAE. I too wonder why no one uses them???

Z

[rjwoods77]

Because it is an atv engine and god forbid any of snooty people(majority) around here would use anything but the latest and greatest thing honda puts out regardless if it is better suited for the competiton. I think smaller engines in smaller cars is the wave of fsae future. Cornell has shown about the upper limit the cbr is gunna go in this competition. Unless they start masterbating with carbon fiber to lighten up the heavy cbr cars that exist, they will eventually go that route I bet. The bar is getting rasised every year and team s like rmit have shown the concept is very viable and very competetive. Now what will be really scary is a sub 300 pound 50hp single that is reliable. Delft,gelph,shmelt? team is getting real close to that. On

[Garlic]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Rob Woods:
Now what will be really scary is a sub 300 pound 50hp single that is reliable. Delft,gelph,shmelt? team is getting real close to that. On </div></BLOCKQUOTE>

Yes they had a very light car, thanks to a TON of that 'carbon fiber' shit you seem to hate so much.

Rob you call FSAE people 'snooty' yet you seem to claim you are smarter than all of them with every post you make. I'm sure once you finally remember to register you'll blow us all away....

[MikeWaggoner at UW]

"Cornell has shown about the upper limit the cbr is gunna go in this competition"

Cornell doesn't use a Honda, genius. Are you drunk?

[Garlic]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by BryanP:
Actually there is a sleeve and piston from the sister engine (Grizzly) that will fit in quite nicely. It gives a displacement of 595 cc. </div></BLOCKQUOTE>

Sounds like a pretty good plan. I wouldn't have expected there would be such a simple solution. Good luck!

[rjwoods77]

Mike,

I am an idiot. I meant to say 600cc 4 bangers. Cbr is on my lips cause the old one we have we are training ourselves on how to program and debug motec. Giving us alot of problems too but it is our fault, not motec.

Garlic,

Dont hate carbon fiber. Just think its use in this competition doesnt meet the intent of this kind of comp. Old post argument. Not worth talking about. Thats all. Never said i was smarter than anyone. Maybe more practical but definitly not smarter. If you cant look at formula kids in that joking light then you have serious tunnel vision. I was just trying to say that many people formula wouldnt even look in that direction because of a prevailing attitude of "gotta be techy or it sucks" Kinda like Honda kids about vtech in the early 90's. Oh boy. Shouldnt have opened that can of worms. Hahhahaha.

Bryan,

That motor is probably the best choice of single cylinder to use because of the incredible amount of availible stock and aftermarket parts for it along with its durability. Torquey son of bitch. Rode one once. Maybe it is just a baja rule but you might wanna check about jackshaft braking. Dont have my rules with me.

[jonno]

The 600 singles are too "lumpy", well that was the excuse I heard. sure they'd produce more torque though. You'd need a beefed up drivetrain though as all that torque arrives in one hit as was explained to me earlier on this thread.
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> The problem that we anticipated with some of the 400 or 450 dirt bike or quad engines is they are highly stressed and blow up too often for our budget </div></BLOCKQUOTE>
This is something i am worried about with our wr450.

[VFR750R]

It seems there may be a misconception of torque. Torque is almost solely dependent on displacement. Almost all 600cc engines have the same potential for torque. A highly tuned single and a R6 for example I bet are within 5% peak torque. And if all else is the same, the R6 will be able to use it's multicylinder format to increase volumetric efficiency with correct tuning. Torque also goes up with intake density, which is what turbos and superchargers do.
Example: a stock CRF450 and CBR600 make the same torque per displacment, although at different rpm so thier hp/l are very different.

I realize I'm being picky here, but it bugs me when people refer to engines as torquey, cause what they are really saying is they don't make any horespower, cause they're going to make the same torque as a high hp engine just at a lower rpm.

Now a turbo FSAE can be refered to as torquey cause it makes the same power as a good NA car but actually has more torque.

[Z]

Quote by VFR750R;
-----------------------------------------------
"It seems there may be a misconception of torque. Torque is almost soley dependent on displacement."
---------------------------------------------

I agree. Looking at the specifications of the past fifty years of racing and production car engines shows almost all have a peak torque of 80 to 120Nm per litre.

The claim that long stroke engines give more torque than short stroke engines (of equal capacity) because of the longer "lever arm" is nonsense (the short stroke engine has a bigger push on its shorter lever arm). Those same 50 year specs show that peak piston speeds are around 20m/s, with some racing engines getting slightly past 25m/s. For a given maximum piston speed a short stroke engine can rev higher. With the same potential torque at higher revs it can make more power. With a larger bore it can have more valve area. So it is tuned to breath better at high revs so that it makes close to its "standard" torque there, and hence high power. So it has short intake pipes and large overlap cams. So at low revs it doesn't breath well and has a hole in its torque curve.

A long stroke engine is never going to rev high (because of the piston speed limit) so it is fitted with long intake pipes, appropriate cam timing, and it gets a slight "harmonic" boost to its torque curve at medium revs. Fit long intake pipes and appropriate cam to a short stroke engine and it makes plenty of torque down low.

Of course, chasing higher revs, and hence higher power, is futile with a "resricted" engine. The restrictor limits the maximum amount of air the engine can breath, and hence the maximum power. A 20mm FSAE restrictor, with standard fuel and "average" CR, gives maximum power of about 60kw (80hp). This can be increased slightly by higher CR (and appropriate anti-knock measures), reduced internal friction, and possibly some other efficiency improvements. BUT NOT BY MUCH!

A turbo or supercharged engine makes more torque because its CR is lowered, giving it a larger "true" capacity - ie. the volume of its combustion chamber. The type of fuel dictates the maximum true CR and trying to cram more fuel/air in the small combustion chamber of an already high CR engine doesn't work. Well, not at low revs because you get detonation, although at high revs the short valve open time means you don't get all the extra air/fuel in there anyway so you're back to an exceptable CR. Anyway, T/S/C engines behave like larger capacity (ie. larger combustion chamber) engines that have early exhaust valve opening. Most of the torque is generated at the top half of the power stroke so these engines have more torque than the equivalent N/A engine.

Well, that's part of the story, as I see it...


Z

PS. (Edit note) The above refers to 4-stroke, spark-ignition engines running "normal" fuel. So it doesn't apply to 2-stroke diesels, or oxygenated fuels (nitrous), or pouring powdered Semtex into the intake...

[Matt N]

Nice work Z. I was considering writing a little rant to complain about but mostly clarify everyone's simplistic descriptions of 'torquey' motors and otherwise. An air pump otherwise known as an IC engine behaves best while within its designed powerband. The whole airflow package which includes intake and exhaust flow, intake volume and tuned length, exhaust volume and tuned length, camshaft lift and duration, and compression ratio of CBR's and other such motors are set up to have a powerband from about 10K to 15K. The CBR hits the restrictor at about 12K (maybe slightly more, but not much) so many teams move their powerband down because it seems pointless to wind the motor out on the restrictor with power falling off. When you decide that your car is geared to have a usable powerband from 7K to 12K, it is easy to say that other motors which have powerbands designed to work from perhaps 5-10K seem 'torquey' in comparison.

The bottom line is the sensation of a 'torquey' or 'soggy' motor is more a case of how well matched ALL the airflow components are to the desired powerband. And additionally, the proper selection of this desired powerband figures into the scenario too. ie. If you have the choice of two engine configurations, one works from 5-10K and one works from 7-12K, and they make the same integral of power from the bottom to the top, (equal power over the usable range, though they might have different peak numbers) the lower rev engine will see less stress due to revs, experience less frictional losses, and if properly designed exhibit quicker transient throttle response... that's just a few of the benefits.

Z, you were right on the money until you started talking about forced induction. A good part of what you wrote there was accurate, but another reason that higher boost works at higher revs is because of the change in combustion dynamics. I know research is currently going into this (I haven't seen a super clear article yet), but it seems that as revs rise past certain levels (depends on the motor, bore size, chamber and piston dome geometry) and with combustion pressures within a reasonable range, detonation seemingly cannot catch up at high revs. At least that's how I understand it. I know some super high (16:1+) compression N/A motors work successfully under this principle, and have read of some high (13:1) forced induction motors that do too.

Matthew

[Z]

Matt,

Yeah, this is a big subject - hard to fit into these little post boxes.

The other big advantage of forced induction is that it allows intercooling. The detonation happens because the air/fuel gets too hot. An intercooler cools the charge part way through its compression "stroke", so for a given CR you've got a cooler charge. Or for the same temperature limit you can have a higher CR, and hence higher thermal efficiency and higher power.

And with direct injection, maybe the fuel doesn't have time to get hot enough to detonate??? But here I am past the limits of my knowledge...

Anyway, Matt, any more on that "even worse (more radical) idea" ... huh...???

Z

[Matt N]

Ill agree the intercooling is an advantage but even an efficient air-air (air-water not really feasible for FSAE) intercooler only cools to about ambient, which a N/A motor breathes anyways... Basically only makes up for the compressor inefficiencies.

The worse (more radical) idea does involve an architecture with one big American piston but now take that idea and pare as many pieces and parts off the design as possible. Think about possibly adding forced induction and really take the design simplification seriously and you're nearly there...

I have no idea if it will rattle itself to death though.

Matthew

[Matt N]

Just to get the haters going out there...

Too bad no nitrous oxide. Combine a big antique american single with the brown go kart described in the other thread and a little shot of juice, and you would really piss some people off at comp, and not because it was slow and ugly - but because it was fast and ugly...

Matthew

[Z]

Matt,

Re: "worse (more radical) idea"

I've thought hard about this, over a coffee...

So, start with big American piston and add as little as necessary. Conrod and crank are simplest way I know of converting reciprocating piston motion to necessary rotating wheel motion. So no swash-plates, scotch yokes, fancy cams, etc.? But, maybe just a half-crank? This was my original idea on the earlier post (p4), using roller bearings and splash lubriction. But the full-crank, plain bearings, and normal oil pump, are possibly just as easy, or easier?

Maybe a flat-head? The low revs and S/C make this feasible. Still need a half speed cam drive, but it makes a more compact package than OHV (most complicated) or SOHC (quite simple with a rubber belt drive).

Maybe direct drive - ie. wheel axles direct to either side of the (full) crank? But this means two sets of clutches and neutral dogs. Besides, even with a S/C the engine would need about 4:1 overall gear ratio. So cancel that.

Do we need the primary balance shafts? Not really, I was just showboating. EFI? A good carb might do (though EFI's are also simple)?

So what's left? A 600cc Briggs & Stratton, with optional supercharging!!! (I heard that at about ~350cc(?) N/A they make ~35hp in those junior drag cars.)


Z

[BryanP]

Matt,
check out our setup in the high school sae car.
We think alike.
Bryan<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Matt N:
Just to get the haters going out there...

Too bad no nitrous oxide. Combine a big antique american single with the brown go kart described in the other thread and a little shot of juice, and you would really piss some people off at comp, and not because it was slow and ugly - but because it was fast and ugly...

Matthew </div></BLOCKQUOTE>

[VFR750R]

Matt N


[I]Only...if an intercooler can do that you now have air at much higher density then an NA engine and you can run it at the same high (efficient) compression ratios. It actually more then makes up for compressor inefficiency cause even 100% efficient compression heats the charge a significant amount.
It's free horsepower, although there are other faults. An intercooler has weight, requires air passing over it to remain efficient, which means car speed effects engine tune. This can be fixed by an equally heavy fan. An intercooler also has volume, which hurts throttle response on a FSAE system. And finally, it has a pressure drop, which is a pumping loss that will lower peak hp on a restricted engine, although average hp will be considerably higher.

I know it has been mentioned before, but E85 works like an intercooler without the weight, volume or pressure drop drawbacks.

[Jeff The Pyro]

has anyone considered sleeving or destroking one of the new Honda XR-650's that've been dominating in the baja races lately (last i checked at least)? being a larger motor, though it is a little heavier than the ~450 motocross bikes, it probably has a beefier transmission and clutch, and as a whole the motor would be running at closer to its designed power level. this would be a similar strategy to the 660 raptor motor...

[skokle]

So guys, what's the verdict on an electric start system for the yz450? I've been looking around and can't make up my mind. For those who know about this engine, how much work is involved? More importantly - how much money is involved? Do you think it's worth it?

[Bowtie Man]

If I remember correctly since the last time I was at a dealer, the ATV's running that engine have a factory setup. I'm not sure if it would bolt up, but that may be a good place to start.

[Dave M]

just found a husqvarna that has a 576cc single, the TE 610: Dual Sport.

It may work well if you can find one.

Thoughts?

[Bill Kunst]

Holy shit, Dave, that is a big chainsaw!! http://fsae.com/groupee_common/emoticons/icon_wink.gif
But really, does anyone sell the Husky? And what is the availability? I have talked to some supermoto guys and they say the only guys rding them are the factory dudes. It might be easier to get an aprilia twin. Anyway, good luck with the fight for better power (notice that I didn't say more).
Bill Kunst

[dfinocchio]

I'm using a YFZ450. Anybody have any single-cylinder Noise Test troubles? Any advice on specific mufflers to look at and/or to avoid? Anybody make their own...and how'd u do it?!
-Dave

[Ecks]

The Cannondale 440 sounds tempting. Its cylinder is oriented vertically, takes in air from the front and exhausts it out the back, which is the opposite of most bike engines. It seems like this would make for a very favorable packaging situation, especially if you were worried about wrench access to a turbo. Any thoughts?

[Ashley Denmead]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ecks:
The Cannondale 440 sounds tempting. Its cylinder is oriented vertically, takes in air from the front and exhausts it out the back, which is the opposite of most bike engines. It seems like this would make for a very favorable packaging situation, especially if you were worried about wrench access to a turbo. Any thoughts? </div></BLOCKQUOTE>


One thought Ecks, dont turbo a single....

[JHarshbarger]

The Cannondale 440 is a very tempting engine; in fact we're using it for the second time this year. It produces good power per weight, it's fuel injected, has a dry sump, and appears to be ideal for a lightweight FSAE car. But it is unreliable. The engine had problems when it was in production and these problems were never fixed because Cannondale decided to drop their motorcycle/ATV line. Also, since the engine was only produced for a few years, they are limited in supply and parts are hard to come by. ATK does service on these engines and sells rebuilt engines that have a "reliability kit" installed, but even those engines have problems.

We've really wanted the Cannondale 440 to work for us, but I don't doubt that we will be moving to another engine next year.

And yes, singles are noisy. The Cannondale 440 has dual exhaust ports which we ran out to dual mufflers pointed in different directions (each outlet is measured individually). It ended up being unbearably loud at the competition and we actually had to be retested for noise after the endurance race because of complaints from the flaggers. We still had no problems passing the noise test though.

[rjwoods77]

I am going to throw this out there again just as I am telling my guys to do next year after I leave. Jawa 500 with a cvt. Modify it to carry extra oil, built a duct with an electic fan for cooling and run alcohol and utilize the 16:1 compression it comes with if they can get away with it. Put a starter ring gear on the cvt stationary pully ala snowmobiles. For you IRS guys lean the engine 30 degrees off vertical toward the rear of the car and put the diff right under the cylinder. Run the cvt toward the firewall and hold the secondary with bearing blocks then run the chain BETWEEN the cvt and the engine block which allows you to run a torsen and mount the sprocket spaced off the ring gear flange a couple inches and you have equal length driveshafts. Firewall to rear axle center line will end up right at 12" center to center. Dont know if you guys ahve ever seen speedway bike racing but the things are fast and engines are reliable. I have been talking to the guys at jawa and they seemed to be real excited with the possibility of jawa powered formula sae. More of a matter of who gets to them first. Use the cvt we are using this year and you can package this thing so tight it would make your head spin. Driving a cvt the thing would intake on the firewall side and exhaust out the back. Stock power is 70hp on meth and i image 50hp would be easy to get. If that isnt enough for you guys remember that Cal Poly Slo finished 13th overall in west on 21hp and Dearborn finish 30th and 31st on 7 and 13hp.

http://www.jawa.cz/

[Rev Hard]

We urgently need CAD model and manual of Yamaha WR 450.
Please mail me at dcemech89@gmail.com


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

[dazz]

Anyone noticed these yet?
http://www.husaberg.com/typo3temp/pics/03225b81ef.jpg
565.5cc
Linky: Husaberg FE570 (http://www.husaberg.com/FE-570.234.0.html)

Certainly challenging the traditional motorcycle engine configuration. Probably too rare for use in FSAE. Thoughts?

[Wesley]

It seems like CG would be prohibitively high on that motor, at least in the stock orientation.

Though packaging might be easier.

[L B0MB]

The output shaft runs in reverse due to the engine orientation in the bike...

From the website: "Compact and light construction with an extremly low center of gravity "

I dont see how it could have a lower centre of gravity when its tilted up on its side...

Maybe they did it just to be different

[Jetser]

On a bike you want the mass as close as possible to the line between the contact patch of the rear wheel and the steering head. Because the bike rotates around this line when turning a corner.