FSAE Powertrain

mclarenlife · Post 07 Feb 2006, 21:29

hey ppl,
i just joined my univ's fsae team in the states and was suprised at the lack of info they had on CVT and drive shaft based powertrains.
we are using a 600cc yamaha engine with the standard gearbox (which is generally of no use since we never get out of first and second gears!). i was looking into the CVT possibility. im pretty sure getting hold of a CVT would not be too difficuly considering that a lot of snow mobiles use them. the problem actually arises when we have to attach it to the engine. removing the transmission from the engine is quite a large project and was wondering how else we could attach it??
about the chain drive. since the engine comes of a bike its pretty simple to implement the chain drive, though i was wondering if we mount the engine sideways we might actually be able to use a drive-train which could then be attached to the rear differential.
any suggestion? - do i stick to the KISS (keep it simple stupid) principle or go ahead in trying to design new components ??
thnx for ur help

monkeyboy1976 · Post 07 Feb 2006, 22:47

Enjoy FSAE. I did Formula Student (UK equivalent) in 1999. We simply used the existing gearbox and geared it down with a huge ratio at the diff end. It was our first full year doing it as a university and hence didn't have the experience to try CVT! Your idea sounds like a good one. Nothing wrong in designing something and maybe creating some proto bits for you to try on the car. If it doesn't work you can use a standard transmission arrangement. Or maybe, if you have time, you could use an old car as a test bed for your design. If the project manager will let you!
FSAE/FStudent is all about acceleration! CVT would go well here I think (I am not an expert however!)
A transerve engine straight into the diff sounds interesting also. Less to go wrong and you could get a great F1 style airbox. Is the Yam a straight 4?

Good luck and keep us posted.

Scuderia_Russ · Post 07 Feb 2006, 22:56

Hiya,
Can't help with the c.v.t. but if you did turn the whole lump around 90 degrees couldn't you fit a sprocket adaptor, and add a propshaft before your diff? I probably wouldn't bolt a sprocket adaptor directly to the diff flange though because you would need something flexible bertween them seeing as their could be movement between the two. (mild chassis flex / slight play on mountings etc.) If there was there would be alot of stress on the shafts.
Something similar to this- I never had the chance to do F.S.A.E. so I don't know the rules.

[IMG:240:180]http://img.photobucket.com/albums/v284/ ... daptor.jpg[/img]

Guest · Post 07 Feb 2006, 23:01

IMO "KISS" Principle is best for FSAE especially if you are starting from nothing. Utilizing the existing gearbox on the bike and use a huge final drive sprocket certainly worked for enough teams and there is no reason why it wouldn't work for you. Of course going the CVT route is going to give you a lot more "learning" out of it, but if you are aiming at going to this year's comp(god I hope you are not deciding this NOW), at this point in time, the simplest route is probably the best.

I am still in FSAE and our powertrain guy is looking at a CVT, but it'll be a multi-year thing and it won't go on the car this year....

mclarenlife · Post 10 Feb 2006, 04:13

well,
yea we are looking at '07 !.. it would kinda be detrimental to be doing designing on a '06 car.
i think i might just settle on a side mounted engine with a sproket adapter and a prop shaft. does ne have some pictures of this? cause i dont think it would be able to take too much load considering that a side mounted engine is going to produce a lot of torsion!

Guest · Post 10 Feb 2006, 14:26

Aston university from the UK have been playing with CVTs for a few years and have run it for the past few events........ not sure what advantage they gain.... as an outsider it seems to cause them some problems with reliability, but good on them for trying!

Mr T

DaveKillens · Post 10 Feb 2006, 19:50

I suggest you look over at snowmobile technology. Some of their engines put out respectable power, and most use a CVT belt.
There is the possibility you could adapt the drivetrain directly from a production snowmobile.

Guest · Post 11 Feb 2006, 10:10

DaveKillens wrote:I suggest you look over at snowmobile technology. Some of their engines put out respectable power, and most use a CVT belt.
There is the possibility you could adapt the drivetrain directly from a production snowmobile.

Alot of the snowmobile are 2 stroke, which FSAE does not allow....There are more than a few teams that runs CVT though, sourced from snowmobile....

When you are talking about cars that generally weighs ~ 450lb, using stock OE parts that needs to be added on to existing installation(ie, adpating a CVT to an exisiting motorcycle engine with built-in tranny) may or maynot be worth the weight. What might be worthwhile are those school that chose to run a single cylinder, with a CVT they can stay in the peak torque band and will definitely help with their inherit power deficit, while the single will be a lighter package to begin with....