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Rear mounted gearbox and diff?
KFC - 30/6/12 at 01:36 PM

Has anyone put in a front engine / rear gearbox??

Soon I'll have a locost haynes roadster and I'm looking at putting in a v6 or v8 and to balance the car up by putting in a rear gearbox and diff. The gearbox I would like would be out of a 2004 formula 3 car, I'm sure it would be very expensive but that sort.

To have a sequential dog ring box would be nice. I know it might be a bit sloppy on and off the power but this will be a weekend car and the od track day. I'm aware of the difficulties of a complicated fuel tank, hmmm, just a thought, I wonder if the tank has to be a specific shape to pass the vehicle test?

[Edited on 30/6/12 by KFC]

[Edited on 30/6/12 by KFC]


ali f27 - 30/6/12 at 02:07 PM

Hi have a look at alfas 75 back end


matt_gsxr - 30/6/12 at 02:11 PM

No specific rules on fuel tank shape for IVA, some even have more than 1 tank.

Might be worth seeing what weight distribution people with v6 and v8's have. Engine is behind front axle, gearbox is central and rear axle and differential are already pretty chunky. Moving the battery might be another option.

Sounds like an interesting project.

Matt


matt_gsxr - 30/6/12 at 02:12 PM

quote:
Originally posted by ali f27
Hi have a look at alfas 75 back end


porsche 944 is another


Volvorsport - 30/6/12 at 02:21 PM

volvo 340 too.....

almost any transaxle could be adapted to a rear gearbox ... (north/south that is)


Liam - 30/6/12 at 06:22 PM

You'll just make it really arse heavy. The engine goes way back behind the front axle and the rear axle is heavy plus you sit at the back too. My V6 engined car is very close to 50:50 and that is 4WD so has the extra front axle weight at the front. Cars with really light engines like BECs can be really rear heavy whereas a CEC, even with a heavy engine is normally just about right for weight distribution.


coyoteboy - 30/6/12 at 07:56 PM

Front engine rear gearbox is just going to help make the car the highest possible rotational inertia. The last thing you want is to put the two biggest weights at opposite ends of a car. Centre of gravity is only part of the problem - a barbell has a 50:50 weight distribution but doesn't rotate too well. Proper place to put an engine and box is in front of the rear axle

[Edited on 30/6/12 by coyoteboy]


KFC - 30/6/12 at 08:44 PM

I had a look at both gearboxes and like the look of the 944 gearbox.

porsche 944 is another



britishtrident - 30/6/12 at 09:26 PM

Volvo 360 is another rear box but it was only 2litre although it was a tough old box.


KFC - 30/6/12 at 10:28 PM

I've seen that someone had a rover v8 is a westfield and the weight distribution was 51% to the front and 49% to the rear. that was with driver and half a tank of fuel.
From memory when I used to work in racing, a f3 car had a weight distribution of 44% to the front 56% to the rear. So I thought it wouldn't be so bad to have a slight rear heavy car so the turn in is still very good.



quote:
Originally posted by coyoteboy
Front engine rear gearbox is just going to help make the car the highest possible rotational inertia. The last thing you want is to put the two biggest weights at opposite ends of a car. Centre of gravity is only part of the problem - a barbell has a 50:50 weight distribution but doesn't rotate too well. Proper place to put an engine and box is in front of the rear axle

[Edited on 30/6/12 by coyoteboy]


KFC - 30/6/12 at 10:53 PM

Hmmm, that does make sense, it would probably end up very tail happy, I like that but I need it to be controllable on public roads.


quote:
Originally posted by coyoteboy
Front engine rear gearbox is just going to help make the car the highest possible rotational inertia. The last thing you want is to put the two biggest weights at opposite ends of a car. Centre of gravity is only part of the problem - a barbell has a 50:50 weight distribution but doesn't rotate too well. Proper place to put an engine and box is in front of the rear axle

[Edited on 30/6/12 by coyoteboy]


coyoteboy - 1/7/12 at 12:00 AM

It wouldn't make much difference mid turn, I think it would only affect turn in and exit, making it less happy to turn in and more likely to flick the tail at the end, but without modelling it it's tough to say for sure just how much difference it would actually make. I was just thinking it effectively seemed to be going in the wrong general direction, not suggesting it won't work for one second.