New Idea - Side Ways Motor, Drive Shaft and a Diff

[Kyle Kapa]

Keep It Simple

[Kyle Kapa]

Keep It Simple

[kwancho]

Advice from one first year team to another: keep it simple.

[Kyle Kapa]

Re: Keep it simple

See thats the thing, this seems pretty simple. Maybe its too good to be true.

[magicweed]

The concept isn't exactly brand new, its been done before. A team from Japan had nice lengthwise setup, complete with blued header, and Guelph used the same design, except they drove all four wheels.

This is my second full year on the team, and looking at our first car, for 2004's competition, to last years car, and now this years car. I can say one thing. The most important thing is getting the car done, period. You don't need a complex drivetrain, any f1 inspired suspension, or a turbo. Just get it finished. A team with a very well executed car last year came in 39th, and put a serious hurt on a lot more sophisticated cars, because they finished it, and did the little things right. I mean, I'm not too proud to admit my car got beat by a Briggs & Stratton.

But yeah, just finish it and you're doing good.

[CMURacing - Prometheus]

if you'll look closer, you'll also notice that a team that didn't finish endurance finished 33rd, and 37th, and 38th...so maybe reliability isn't everything...

[Kyle Kapa]

So maybe i'm asking the wrong question than...

What is the most simple and reliable drive train setup?

[CMURacing - Prometheus]

you'll probably get the reliability you want from your shaft drive setup, but you'll pay for it in weight, unless you do a trick carbon-fiber thing. you're also right in that its (mechanically) a bit simpler than a chain drive setup, but since the bikes are built for chain drives anyway, and transverse mounting, its by far the easiest packaging and setup answer.

don't abandon that design because people here are complaining, though. usually an unconvential approach takes longer to get right than the mainstream one, and this is why everyone discourages these things for first-year teams.

[DaveC]

Well, the chain is how the tranny transfers power on the bike, so its ready to go with little likelyhood of any major "issues" coming up. Its difficult to forsee every "issue" that can arise when modifying things, especially since most of us here havent been wrenching on cars for a really long time.

Bolting a driveshaft onto the same tranny shaft that supports the chainring will change the forces on the trans shaft. I have no idea if it will be an issue or not, but its the first thing I'd consider it I was going to tackle the job.

I do think it could be worth looking into, but Its definately not a new idea. Maybe someone who has done all the research on it will read this...

[J. Schmidt]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> What is the most simple and reliable drive train setup? </div></BLOCKQUOTE>

...chain drive to a sprocket on a solid axle. If you don't want to scrub the tires around a corner than go with a spool or some other differential. There are various diffs that offer different advantages and disadvantages, it depends on how you want the car to handle, how much fab you want to do, and how much you want to spend (sponsors, baby!). FYI, there really is no "best" setup, but there is a reason why most teams run a limited slip.

[Bowtie Man]

With a shaft drive system you may have final drive ratio problems that the gearing in the engine can't account for. I'm not sure what the atv's come with just a word of warning i guess

[CMURacing - Prometheus]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DaveC:
Bolting a driveshaft onto the same tranny shaft that supports the chainring will change the forces on the trans shaft. I have no idea if it will be an issue or not, but its the first thing I'd consider it I was going to tackle the job.

I do think it could be worth looking into, but Its definately not a new idea. Maybe someone who has done all the research on it will read this... </div></BLOCKQUOTE>

according to our dyno/engine guy, "most" teams that have engine dynos have shaft drives from the transmission...including us. however, our shaft drive for this is beefy; after the spline adapter for the output shaft, its just a steel keyed shaft with high-rpm u-joints at either end.

[DaveC]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">If you don't want to scrub the tires around a corner than go with a spool or some other differential. </div></BLOCKQUOTE>

Quick correction, a spool is not a differential by definition. It fully and permanently locks the left and right together. I'd go with some type of limited slip differential.

Bowtie, good point about the gearing. I'd add that gears in diffs are not quick, easy, or cheap to switch out. I actually like setting up diffs, but gears and install kits are not cheap. Something to consider...

[magicweed]

My bad, I forgot that UTA, RMIT, and A&M all had endurance failures. I guess we were too busy trying to fix the broken cables and pedals on our car, so we could run in the endurance for the people not expected to finish it.

This is why I reiterate, make it reliable.

[welder]

A lot(all??) of the Lotus 7 clones that are converted to bike power use this method of power transmission.

I believe a commercially available coupling can be purchased in the UK for Fireblades and the other superbikes. Not sure whether a 600 would have the same output shaft though.

Probably worth a few questions on the Westfield/Locost/Bike-engined cars forums to see if they have had any major issues.

I'd also be interested in seeing what sort of drivetrain losses you would have compared to a chain drive.

BTW aren't there several "formula Suzuki" cars still over in the US with a longitudinal Hayabusa installation.(as well as the Legends)
Anyone know how power got to the wheels on those?

[jsmooz]

magicweed - Thanks for the compliment as I'm a member of the Briggs powered team.

Kyle - That design has been done. We had the longitudinal output and ATV diff. The good thing about it is that if you're a small team with a lack of man power you can purchase more parts and make small modifications to them. Why re-invent the wheel? As others have already said keep it simple. We had all new people last year designing an all new car. Our main goal was just to finish every event....which we did. We didn't do awesome in very many but we got points. As stated we finished 39th overall (with 18hp) ahead of some very big teams because we finished every event.

Pic of our rear-end here:

http://evilallianceracing.com/ipw-web/gallery/FSAE05/IMG_1770

[drivetrainUW-Platt]

for longitudional engines and atv diffs talk to Guelph (awd car) and the one team from overseas with the powdercoated light blue frame.....

[Ben Beacock]

If you want simple, the diff and longitudinal engine works well. Our first car had one driveshaft part: a steel tube splined straight through. The engine male splines matched the diff male splines-- both suzuki. This setup included the diff's u-joint to account for our 'first-year' shaft alignment capabilities. Second year we switched to a lovejoy style joint. Last year it was just a bolt on flange with some modified diff internals.
Every year, the diff got closer to the engine and more stiffly mounted (better weight dist, and shorter wheelbase)
If i was involved again this year, I'd be making a new diff housing to get the axles right behind the engine and run outboard brakes.

other advantages of longitudinal mounting:
-exhaust doesn't heat the firewall or fuel
-diff:no bearings or sealing issues
-the exhaust looks wicked
-ring and pinion gearing is very compact. lots of room to mount things behind the engine
-no shielding required

disadvantages
-engine mounts aren't as easy to make, and harder to design semi-stressed
-clutch changes are a pain

Thats all I can think of right now. I'm still trying to accumulate all my diff internal and installation pics so I can make a little website or wiki or something.

[SeanM]

we're running the same idea, we use a yamaha raptor motor rotated so that where the sprocket would normally come out was facing the back of the car then the had a local machine shop make a drive shaft that would fit into the motor and into the raptor diff. it isn't to complicated of a design the only thing hard about it is getting the drive shaft made.

[Erik Whoa]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Bowtie Man:
With a shaft drive system you may have final drive ratio problems that the gearing in the engine can't account for. </div></BLOCKQUOTE>

That should not be a problem. You will still need a ring gear to transmit power from the sahft to the diff. That gear, along with the bevel/helical gear on the shaft, can be adjusted to give you many different ratios.

[MikeBlommel]

You may want to check out some parts that are made for Dwarf race cars. They use a front-mounted longitudinal bike engine driving a Toyota live axle with a driveshaft. Your idea of a longitudinal mid-engine could possibly work using some of the dwarf parts and a short driveshaft.

Check out http://www.dwarfcarracing.com and http://www.hawkmachine.com for some more info. Under "parts" Hawk makes an aluminum driveshaft adapter to fit the splined shaft on the tranny where the chain sprocket usually goes.

I'm just wondering how this setup would compare to the usual FSAE chain driven diff setup most teams use when it comes to weight and drivetrain losses.

I like different ideas and this sounds kinda cool. You may also want to do some research on UK built bike-engined cars. From what I can remember there can be some oiling problems when you turn a bike engine north-south and apply cornering and braking loads. I believe some of those cars utilize different sumps to avoid the problem.

Good luck!

[BryanP]

Check out page 5 " New photos of High School formula Sae Car". Notice the first photo of the drive train. The setup you have discussed is reliable, inexpensive, light, and quite easy to complete. If you would like more photos and info. PM me
regards
Bryan