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BEC powertrain for a 3-wheeler
palacajoe - 11/9/06 at 05:50 PM

I'm in the planning stage for a 3-wheeler, and I'm hoping for some input on my powertrain and, perhap, some recommendations on reading material and suppliers. I'm going for a marriage of the Locost and the Volkwagen G3X. Here's what I have in mind:

High-powered bike engine (Hayabusa?)
Front-engine/rear-wheel drive
Shaft final drive
Reverse gear

Some of the things I'm mulling over are:

engine
weight distribution
driveshaft setup
fuel tank placement
rear suspension arms (purchase and/or fabrication)
mounting a car wheel on a motorcyle shaft

Any thoughts?


smart51 - 11/9/06 at 07:09 PM

The grinnal scorpion has the best idea. If I were designing a BEC 3 wheeler, I've copt that.

Put over simply: Take one motorcycle. Remove the front forks. Bolt to the front half of a seven chassis (cockpit and front wheels). clother in curvy body work. Voila.

You keep the bike power train exactly as it was intended, but you put a car tyre on the rim. No worry about oil surge.

Don't like a chain? Use a bike with shaft drive.
Don't like the tall gears on the light weight bike? Fit a 15" wheel in place of the 17" if you can find one.


dl_peabody - 11/9/06 at 07:12 PM

The VW used a car like powertrain....depending in where the drive axels fall you could modify one of the drive axels to carry a sprocket.
Just and idea.

A FWD Car and your job would be half done but it sounds like you are set on RWD BEC.

3 wheeler handing
http://www.rqriley.com/3-wheel.htm
http://designmassif.com/trihawk/articles/3wc/article_text.htm

http://thekneeslider.com/archives/2006/01/03/sub-3-wheeler-with-suzuki-power/


Good Luck I hope t here more about your project


palacajoe - 11/9/06 at 08:02 PM

The Grinnall is a real beauty. Seeing one near my home a few months ago is what got me interested in three wheelers and building a car in the first place. However, aesthetically I prefer a longer front end and shorter rear end on a car, and research I've found (which may simply be anecdotal) indicates that front-engined three-wheelers are more likely to stay on three wheels.

I only briefly considered front-wheel drive when I saw the Peugeot 20cup, which is rear-wheel steered.


kb58 - 11/9/06 at 08:04 PM

quote:
Originally posted by smart51
You keep the bike power train exactly as it was intended, but you put a car tyre on the rim. No worry about oil surge.



Not true. The car doesn't lean like the bike would, so there certainly is surge. The Megabusa has a dry-sump to cope with oil starvation, and what you're discribing is no different.


smart51 - 11/9/06 at 09:11 PM

The engine will be facing the right way and so there'll be less surge than in a seven. Bikes do lean into the corners but there will still be some oil surge. in a 3 wheeler it will only be slightly worse. A baffled sump may be all that is needed rather than a dry sump.

[Edited on 12-9-2006 by smart51]


palacajoe - 11/9/06 at 09:26 PM

quote:

The engine will be facing the right way and so there'll be less surge than in a seven.



That brings up an issue that I've also wondered about.

Normally in BECs the engine is turned sideways, but (and here I may just be showing my level of ignorance) since my car will be using a motorcycle final drive, could the engine me mounted the same as it is it the motorcycle? Of course the driveshaft would have to be lengthened.


Guinness - 12/9/06 at 07:07 AM

When I was doing my research into kit cars, trying to chose a kit, I was very interested in the Malone Skunk.

Front engined, transverse mounted, shaft drive to the rear wheel. It uses camber control front suspension too which helps stability.

Don't know what happened to them, as the link to their website doesn't work anymore, but http://www.3wheelers.com/malone.html has some info.

Malone Skunk
Malone Skunk


Hope that helps

Mike


russbost - 12/9/06 at 05:18 PM

With a 3 wheeler & the engine mounted as it was in the bike I doubt you would ever generate enough G force to cause surge. I've got my engines mounted transverse, as in the bikes, they are bog standard & I've never seen an oil light even flicker depite lapping the occasional roundabout - considering I have a total of about 22 inches of rubber at the rear I don't think you'll match that with a 3 wheeler.
I've always felt the Grinnal type setup should work well, but I was told (by Ian Hyne of Kitcar mag who should know what he's talking about), that they swap ends very easily, too much power, not enough grip - anyone know if this is the case?


smart51 - 13/9/06 at 07:15 AM

Scorpions don't have too much power. 130 BHP from the 1100 IIRC. They have lots of tyre too but that doesn't neccesarily mean grip.


Johan - 25/10/06 at 10:13 AM

Check www.mride.se

BR
Johan


G.Man - 25/10/06 at 11:01 AM

quote:
Originally posted by smart51
The engine will be facing the right way and so there'll be less surge than in a seven. Bikes do lean into the corners but there will still be some oil surge. in a 3 wheeler it will only be slightly worse. A baffled sump may be all that is needed rather than a dry sump.

[Edited on 12-9-2006 by smart51]


Sorry Smart51 but this is rubbish, the engines face the right way in a Radical, in a sidecar outfit and in many other mid engine vehicles... the surge is caused because the car does not lean, therefore the sump is not "outwards" of the centripetal forces...

Surge is not a product of the engine mounted sideways, as the biggest force is braking and acceleration, but our engines fail under cornering, which is the same force as braking and acceleration in a natural application...



[Edited on 25/10/06 by G.Man]


vealmike - 27/10/06 at 02:28 PM

Sorry, but this is going to be controversial reading for a couple of posters.
Firstly the cornering forces with a 3 wheeler can equal those of a four wheeler. Let's not forget the infamous 1920's Morgan that out did a race prepared Sierra Cossy in the early 90's

So I'm afraid that 24" of rear rubber won't help lose a trike on the twistys.

A well set up trike should out corner a four wheeler due to it's lower moment of inertia.

I'd also advise more than an oil light on a bike engine as a surge warning. By the time the oil light comes on in a bend, your engine will be trashed. Get a proper oil pressure sensor and needle, better still a data logger before you consider a track day.

Roundabouts probably won't do much harm, unless you go right the way round. It's long high G bends that will lead to oil starvation. And you may find that right hand turns are OK, whereas lefts will kill your bike engine. See below.



For the second poster, bikes lean into a bend, and the oil stays flat in the bottom of the sump - no surge.

Cars and trikes (without active leaning) lean to the outside of a bend, and all the oil in the sump will also move to the outside. You should therefore find that you are fine turning one direction, but will kill your engine if you turn the other way.

Hope this helps explain things.