PistonHeads.com Forum

Mid Engine AWD, Front Gearbox?

Mid Engine AWD, Front Gearbox?

Author
Discussion

43655

Original Poster:

40 posts

81 months

Tuesday 1st August
quotequote all
I know this has been covered before but has anyone successfully done it or seen it done running the transaxle in front of the engine?
All that I can think of is the Audi R8 & Lambos which use the Oerlikon Graziano gearbox, but the stock gearing is crap sadly for a relatively low-revving engine.

A little background, tube chassis build, Lexus 4.3 V8 (future twin turbo) so Porsche trans would have been the go-to but they're both rare and expensive.
Doing this the gearbox choice is broader and cheaper, although I admit i know little about running a transfer case and separate diff (as far as suitable choice goes, for a road/track car with potentially over 600whp)



Despite being somewhat heavier, the mass of the drivetrain would be considerably better centered (bear in mind a standard transaxle has some 90% of its mass behind the axle!)

I figure it could be configured as a RWD only setup initially, then add on a diff, propshaft and front diff.

for this out of curiosity...

stevieturbo

12,636 posts

169 months

Tuesday 1st August
quotequote all
Other than the drivetrain wanting to drive the car in reverse with that layout, it would work.

You'd need to flip the F/R diffs to get forward drive in all normal gears.

if that's the layout you want, even Porsche drivetrain wouldnt be suitable.

Emanresu

211 posts

11 months

Tuesday 1st August
quotequote all
Couldn't you just flip everything backwards then use an engine the turns backwards, s2000 for example?

43655

Original Poster:

40 posts

81 months

Tuesday 1st August
quotequote all
Could easilly be changed by inverting the diffs or yeah swapping front rear although I have no ideas yet in which I'd use.

Porsche box gets used all the time, the gearbox is both upside down and the wrong way around, giving 4/5/6 forward gears etc as normal. The trouble is a good one is £7k+. Most transaxles are either too weak, the wrong way up (driveshafts under the input shaft which would put the engine undesirably high) or just crazy money.
BMW gearboxes are getting popular for UZ-FE conversions for being cheap and strong, and they're surprisingly compact too, which led me to start considering this layout again

Max_Torque

11,521 posts

139 months

Tuesday 1st August
quotequote all
The off road boys have been doing this for donkeys! Way back in the early 90's we were building buggies with rear mounted RV8s, pointing forwards, running a saloon car box, and a short prop to the xfer case under the front bulkhead, and a prop all the way back to the rear diff, using axles with the centres cut out and flipped.

The issue in a small car is always that the big bell housing is right where the occupants butts need to be, rather than where their feet are, which forces a wide apart seating layout.

Andy Burtons PugCossy had similar layout, as did the metro 6R4 of course:


Advertisement

Mr2Mike

17,640 posts

177 months

Wednesday 2nd August
quotequote all
Emanresu said:
Couldn't you just flip everything backwards then use an engine the turns backwards, s2000 for example?
The S2000 engine doesn't turn backwards.

chuntington101

5,640 posts

158 months

Thursday 3rd August
quotequote all
Are there any cheaper gearboxes like the GTRs that would incorporate a gearbox, transfer case and front diff in a single unit? Would make the install a little easier regarding the passenger area.

stevieturbo

12,636 posts

169 months

Thursday 3rd August
quotequote all
chuntington101 said:
Are there any cheaper gearboxes like the GTRs that would incorporate a gearbox, transfer case and front diff in a single unit? Would make the install a little easier regarding the passenger area.
GTR's do not do that

chuntington101

5,640 posts

158 months

Friday 4th August
quotequote all
stevieturbo said:
chuntington101 said:
Are there any cheaper gearboxes like the GTRs that would incorporate a gearbox, transfer case and front diff in a single unit? Would make the install a little easier regarding the passenger area.
GTR's do not do that
The new ones do it the other way around. Engine front and gearbox, centre diff, etc. in the rear.

It you ran it in the opposite orientation It would still require the gearbox to be in the way but would be where a normal gearbox would be on a front engined RWD car.



stevieturbo

12,636 posts

169 months

Friday 4th August
quotequote all
chuntington101 said:
The new ones do it the other way around. Engine front and gearbox, centre diff, etc. in the rear.

It you ran it in the opposite orientation It would still require the gearbox to be in the way but would be where a normal gearbox would be on a front engined RWD car.
New GTR's run a rear transaxle type arrangement. But they still require a front diff. They are also inherently RWD with a clutch pack to send drive to the front. So not really a centre diff in the usual sense.

To try and reverse one of those would be a lot of work.

Older GTR's are much like his drawing, old Fords etc etc

prof

17 posts

188 months

Thursday 17th August
quotequote all