Hey people. Recently I've been toying with the idea of building a RWD project car in my spare time. I want to frankenstein together a rear engine, RWD car, and mount my own custom fiberglass body on it. In short I'm trying to build a rear engine kit-car for as cheap as possible. Couldn't find anything like an MR2 locally, so I'm trying to build something using a local car yard.
My idea is to take a front wheel drive car (like some volkswagen), and take out the engine and tranny, which would look something like picture #1, minus the axle and wheels. Then by finding an AWD or RWD car, I would mate one of the outputs from the FWD engine and transmission, to the drivetrain going back to the rear wheels from the RWD/AWD car. The end drivetrain would look something like picture #2, although more compact and with the engine sitting longitudinal in the back of the car over the rear diff.
One more thing is I would really like to have the engine longitudinal rather than transverse, because like I said earlier a Mclaren F1 is the format I'm looking to get.
Any good thoughts about this, or am I completely crazy? Thanks in advance
Picture #1
Picture #2
While I would love to see this happen, is there a particular reason you're tied to this layout?
Your second picture looks like a mid-engined car, except with the crank pulley facing the rear and the output going to a transmission that has a shaft to move the output to the rear.
Anything is doable, but that's a lot of work unless you really want that result. You could potentially mount the engine the other way, and then maybe find a way to reverse the gearing? That might be a tall-order but it should be possible. Have the crank facing forward, a transaxle right over the rear axle line, and then two axles out to the wheels.
EDIT: To clarify, I mean use an AWD transmission and block the rear output.
EDIT EDIT: Actually, with a front engine AWD transmission you wouldn't even need to reverse the output. You would have some extra weight hanging out behind the rear axle though.
It would be incredibly slow too as the rear differential is being turned by an axle that has already gone through the gear reductions
of the transaxle......
In reply to WondrousBread :
The only reason I'm tied to this specific design is because all mid engine sports cars have a longitudinal engine layout, and I like the look. (so I might change my mind)
"Your second picture looks like a mid-engined car, except with the crank pulley facing the rear and the output going to a transmission that has a shaft to move the output to the rear." That's what I'm going for, a quick and cheap mid engine car. I only have the engine flipped around in the drawing to save space, I thought the engine could sit nicely over the diff. Not at all opposed to flipping it, although that might push into the cab too much.
"Have the crank facing forward, a transaxle right over the rear axle line, and then two axles out to the wheels." That would be the ideal way to do it, and how its done in race-cars, I just want to build this cheaply and don't know where to source a transaxle like that (the pic below) as I don't think they're used in anything you could find in a car yard. Although by all means tell me if you know what common cars have some better part in them!
Subaru transaxle can be converted for RWD use.
VW Passat transaxle .............
Wow, that will work awesome! Thanks for the information
It is the B5 platform ...1997 - 2005 ...you could get a turbo 4 cylinder too :)
TurboFource said:
VW Passat transaxle .............
Do you know what model years they ran that transaxle? I'm not really a VW guy.
Not a VW guy either...97 - 05 ..... I believe
TurboFource said:
It would be incredibly slow too as the rear differential is being turned by an axle that has already gone through the gear reductions
of the transaxle......
I've seen this done on a people carrying tram.
It had a 3.3 liter Mitsubishi engine out of a early 90's dodge minivan. Front wheel drive transaxle four speed automatic.
Top speed was around 25mph.
Why not use picture 1 at the back of the car, like the fiat X1/9 or the Pontiac fiero.
why not use an audi drivetrain and FWD gearbox. seems overly complex. GT40 replica/Ultima guys have a lot of this figured out
But a 1.8T from a passat would be easy
Here's some older discussion from here that might be of use to you:
https://grassrootsmotorsports.com/forum/grm/transaxles-for-longitudinal-mid-engine-setup/44319/page1/
Probably not what you are going for, but a light, cheap option might be from a longitudinal FWD early-80's Toyota Tercel (or whatever they were called in your market, and if you can find one.) In theory, the 16V EFI twincam 4A-GE from an MR2 or Corolla coupe could bolt up to the transaxle, but that might be a recipe for discovering just how weak the transaxle is. Shift mechanism would need to be custom fabricated, but with a project of this scope that is only the tiniest drop in the bucket.
TED_fiestaHP said:
Why not use picture 1 at the back of the car, like the fiat X1/9 or the Pontiac fiero.
I'd do that, but after calling 10+ buisiness's, the closest mid engine car in a wrecker is a about 1000km away.
TurboFource said:
It would be incredibly slow too as the rear differential is being turned by an axle that has already gone through the gear reductions
of the transaxle......
Yep, often intentionally used on rock crawlers for this reason.
Leviathan888 said:
TED_fiestaHP said:
Why not use picture 1 at the back of the car, like the fiat X1/9 or the Pontiac fiero.
I'd do that, but after calling 10+ buisiness's, the closest mid engine car in a wrecker is a about 1000km away.
Don't call businesses. Check Facebook Marketplace and Craig's List. I have bought four X1/9s in the past couple of years, and none of them were advertised by a business.
NOHOME
MegaDork
2/5/23 10:08 p.m.
You can do a Porsche or a VW or a Pantera or a WV or a Subaru drivetrain hind the seats. They will all work.
But you want CHEAP and you want Easy, so think Honda
Here is a Honda Civic engine moved from the front to the rear. Easy AND cheap. Cheap Turbo make fast. Friend of mine is building it to fit under a Morris Minor. In reality it could fit under anything you and your welder want it to fit under
You did not say what body it needs to fit under. However, if possible, I would harvest the entire front sheet metal structure to include the suspension mounts, k-member and rear firewall and install as much as I could behind the recipient's front seats.
Agreed on the VW B5 Passat option - 97-05, or modified Subaru trans and any of a wide variety of engines.
If you go the Passat route, you can use the shifter and linkages on the trans from a 5 speed Boxster. The Subaru route requires a little more engineering, but it's been done a lot. May even be able to find a kit since it's the heart of the Factory Five 818.
NOHOME
MegaDork
2/5/23 10:31 p.m.
I am not afraid of much, but mating an engine to a gearbox that was not joined in holy matrimony by a single manufacturer is a deal breaker. The novelty of pulling the engine and box out of the car to figure out why it is broke again, gets old in a hurry.
Also, if you go ahead, think long and hard about how you are going to service this thing should it require mechanical repairs in the future; can you get a stuff?
I would go autobox, because any negatives are balanced by not having to make the shift linkage.
Just going to leave the master of FWD transaxle fitted in the rear, here, and leave....
MONZORA redux: ‘65 Corvair + ‘94 Corvette mashup for 2019 Challenge
In reply to NOHOME :
Yes, this is the other option. Just moving the entire engine and transmission to the rear end. Only reason I'm kind of leaning away from this is because I think this route would require more fabrication and custom fitting, which I lack lots of experience in. As for the body, thats a second priority. Ideally I'm building a replica supercar body to fit on it, but I also could put a race shell on it and just make it fit.
In reply to Autovelox :
I'm on Vancouver island in B.C, Canada, and the closest X1/9, Fiero, or MR2 for a decent price is in Ontario, some 10+ hours away. I've spent days checking every marketplace and car yard around B.C, and all there is is finished stuff way out of my price range.
Moving a FWD drivetrain to the rear is by far the easiest method here, and it's almost definitely going to be a transverse engine. You'll end up with a mid-engine setup but that's better than rear engine anyhow :)
If you really really really want rear engine, best to start with a VW transmission and an adapter. There are many of them out there. While you can flip a Subaru transmission to run backwards, it's going to cost you a fair chunk of change - BTDT.
You might want to look into the Goblin and Kimini builds.
