Automatics in GT-40's

[Pete T]

The old Toro/Eldo transaxles are longitudinal and are based on the turbo 400. They are basically bullet proff. I know of a Kelmark GT with an injected 700+HP ZL1 BBchevy using a Toro transaxle. The biggest problem was that the best R & P was 3:23 from the factory. However, there is a company that makes a 3:73 for these. The R & P is 9.5" in diameter and can be built with most of the HP parts for the turbo400. There are also shift inprover kits available.

There was a 911 on e-bay a few months ago with a chevy small block and one of these.

These transaxles (TH425) came on Eldorados with 425, 472, and 500CI v8's and the toro's with 425, and 455 v8's. They are also relatively cheap. You can get these from the local Pick-n-Pull for about $75. I just sold the one I had a few months ago. I was going to put it in the back of a Beetle with a small block chevy, but I needed to thin down my projects.

 

[Pete T]

Just remembered, I had a friend that built a Cimbria SS kit car (a long time ago) with a TH425 powered by a 302 Ford.

 

Why dont you graft a stockcar auto that discards the converter and uses a bypass tap for neutral on to an IRS Quick change centre section. You can buy them in a 'shorty' version which would suit the GT40 application. At least the shifter would be a no-brainer! Just make an extended input shaft/pump drive and your done. We ran one in a 406ci C******** with no problems ( thats the tranny in normal configuration)

Jac Mac

Interesting !
Might you have a pic of this set up ?
or a site that would give more insight on it ?


Thanks ! Curtis

 

[Pete T]

I'll look when I get home tonight. I know I have some info. Insidently, I forgot to state that the TH425 was also used in GMC motorhomes and the company that makes the R & P developed it for those.

 

[Pete T]

Here are a couple of links:

Jim Kanomata GMC Parts and Services

They have ring and pinions

Fiero swap site with info an using the TH425, TH325 and TH325-4L (the 325-4L is based on the turbo 350 and is 4 spd)

Longitudinal V8 - FieroAddiction.com

I'm looking for the site that has the Beetle with a 500 caddy and TH425 in the rear and there's one with Lambo kits.

Pete

 

[J. Salmon]

Not sure if this adds much or not, but my experience with Audi auto vs. manual transmissions suggests that the manuals can handle significantly more power. This is purely based on A4/S4 and A6/S6 platform AWD cars with turbos. For example, my current allroad has the 2.7T motor which is 250 hp/250 tq stock. The chip tuners will not push the auto tranny beyond 300 tq becuse they get tranny failures. There are guys running over 400 hp and tq at all four wheels through the stock 6-speed manual without issues beyond the clutch. Hooking a 302 Ford - even in "low" tune - to an auto designed for a 200 hp motor may result in some difficulties (though I have no real data). ]

And I second Ron's tiptronic sentiments: despite buttons on the steering wheel or however you want to set it up, it's only marginally better than a regular auto - not that there is anything wrong with that...

 

[Eric A.]

Does anyone have any idea how durable the Chrysler automatics might be if used behind a V8? I have had several people ask me about what automatic would work for a mid-engine installation with a V8.

 

[Jonathan Strain]

If I remember correctly the V6 engines Chrysler mated those transaxles put out around 250 horse. They seem to hold up well at that power range so there is probably room for more. Especially in a light weight car like a GT40.

 

[Dave Wood]

The old Toro/Eldo transaxles are longitudinal and are based on the turbo 400. They are basically bullet proff. .

NO they are not longitudinal, they are "parallel". The engine drives a "Hy-Vo" chain to the side mounted transmission and it is attached to the rearend section that drives the wheels. They are very WIDE and require a custom chassis to mount them in. A couple of side notes, their sprag clutch is installed backwards of a regular rear drive car, in case someone works on one, ask me how I know. The second is that they were made under a Ford patent that Ford developed in the early 60s when they were contemplating a front drive 'bird, so if it wasn't so huge would be kind of appropriate.With the size of the boats that they were in, they should be indestructable in a car the size of a GT40.

 

[Lynn Larsen]

Chill Wood!

The V8 is longitudinal, not the transaxle.

If anyone remembers these GMC motorhomes, well they had a GM 454, if memory serves 'cause it used a lot of gas at 65-70mph, with the Tornado drivetrain. I have driven the motor home cross country twice and they won't even know they are pulling anything with a GT40, but, damn, what a hunk of iron to use.

Lynn

 

Does anyone have any idea how durable the Chrysler automatics . We started out with the Chrysler automatics. We found the week link is the aluminum can around the clutch pack. we looked in to making our own out of stainless . but opted to make our one transaxel instead. I have one of the ones out of the higher output Prowler left we did not molest it. Low miles I have $700 in it. It will Handel 325 hp just fine in a 2600 pound car. and an be converted to paddle shift.