924Board.org

[Scott Sanda]

Hello everyone, I'm looking for advice. I have the heimrath 1982 tube chassis 924 GTR, there are pictures and stuff about it scattered around on this site and others. When i bought it waaaaay back in 2007, it had a 944S2 Motor in it, which morphed into a full on Mike Mount 968. Car also has an aluminum torque tube, and an actual GTR forward gear cluster transmission.

A couple years ago I brought it out of retirement, re tuned it and cut the rev limit a bit(full EFI and motec), and ran a couple of races for fun.

I want to start running it a lot again, and am going to put in the Audi/Porsche 1.8T as built by Motorworks. Everything i have seen indicates these run forever, make more power than the 968, more reliably.

The front end work is going to be pretty straight forward. My question is related to torque tube and transmission.

I could just keep the current tube and GTR transmission in her, (I also have a duplicate geared 924 turbo snail box spare). However, this box is literally one of the few remaining in the world, and rebuilt parts for it are like hens teeth. I don't really want to hurt or use it when it belongs in a museum.....

The recommendation is a cayman GT4 transaxle. Again, this will fit and putting it in is straight forward enough mechanically, with the exception of the torque tube.

I am going to need a standard 944 tube, with the rear bell housing.

Where might I find one, with fresh bearings, in good shape. Hell, where might i find 2?

Does anyone know of an adapter kit that is already designed that might mate the 924 snail shell tube to a standard bell housing 944 type transmission?

I don't have a standard 944 tube to take measurements on for comparison, is there a drive shaft length difference between them?

If the shafts are the same length, making an adapter plate isn't going to be that difficult, but i want as much information as possible before I start.

Any input will be greatly appreciated.

Scott

[Fasteddie313]

Iirc the snail tube is quite a bit shorter than the 44 tube because the snail rides more infront of the rear wheels while the 44/Audi boxes ride more behind the rear wheels...

But.. mike9311 is making custom aluminum torque tubes...
http://www.924board.org/viewtopic.php?p=403429&highlight=#403429

I don’t know if he has the time, or what it would cost, but I think he could make just about anything you could need..
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80 Turbo - Slightly Modified

[Carrera RSR]

Is it this car? https://www.racingsportscars.com/photo/1981/Mosport-1981-09-13t-007.jpg
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[morghen]

There are several options, i'm sure Motorworks have their own as well which they could provide with the engine...i think that would be the best option.

Or you can just use a regular 944 torque tube and a vw gearbox as those are plentiful. Not sure how those handle racing but i bet some are made to.
The 1.8t probably is made to bolt the 944 TT and there is a coupling designed to fit a VW/Audi (literally VW/Audi) gearbox to the 944 TT.
I designed that coupling and Mike could produce it for USA use (i already had a short talk about this with Mike).
The first coupling was already made and as far as i know used on a SEMA AAN engine swapped 944 show car.

I would not use the snailshell or the GTR box for the same reasons you mentioned.
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Supercharger and EFI kits
https://www.the924.com

[Scott Sanda]

We are talking to Motorworks, and what they have done is top notch.

But this is a Tube car, and everything they have revolves around the tub cars with a "normal" tunnel and front suspension cross member.

I'm trying to not cut up the car to do this, so the only real option is to buy the stuff, and mock it up, and see what we see.

I have no real worries about the motor, other than routing the exhaust out of the Turbo. The front suspension triangulation and tubing gets in the way of their "normal" route.

it's the back I am most concerned about.

Scott

[Scott Sanda]

Carrera, it is really hard to tell. There are a couple different pictures out there of Heimrath cars from the time frame, but you cannot really see into the car to see the cage and chassis well enough to be certain.

HR00182 is stamped in the cowl, and I confirmed at length and with pictures talking to Todd Holberts and Tom Seabolt that it isn't the Holbert 82 car. They used square tube, and this is all round.

I also talked to Ludwig Jr. back when I bought it, and he had exactly zero pictures of the build or car, although he remembered it and described things accurately.

The real issue with this, my DP car, and a lot of the period cars is that they were race cars. No one preserved the "proof" of origin. My DP car is the one Tom Brennan won the GT3 runnoffs in, has GTR rear suspension, all sorts of trick stuff. Can trace it all the way back to his hands. But, no factory serial number.

Tom routinely cut the shock towers off (where the Sn was located) and threw them away. He I I were crying in our beer over that a couple of months ago, as he has one of his DP cars with no SN as well, and that really cuts the resale down.

Same issue with the GTR. Factory A, B, C pillars and rockers as required by the Trans Am rules, but everything else including factory numbers is gone, and has been since the build.

Anyone want a working GTR transmission?

[Carrera RSR]

Just wondering if it were one of the original factory GTR's or one of the US built GTR 'kits'. I'm no expert, but am I right in thinking the tubular chassis were the USA built cars with GTP bodies? I need to read up more on these cars. So excuse my ignorance
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Carrera RSR]

I guess at least the Motorworks engine can be installed easy in the USA and is turnkey with local support.

One part of me likes the idea of originality. But as you say, a lot of race cars evolve over years and are not 100% as they started.

As long as its used.......does it matter what motor is in it?
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[Scott Sanda]

There were no US built Kits, for the 924 GTR's. You are thinking about the D production 924 Kit car.

That was a NA car built for SCCA Club racing. Ran in Dprod, then in GT3.

The 924 GTR's were all factory cars. Running in Trans Am and in IMSA and internationally.

Some of them were cut up and turned into tube chassis cars by various teams.

Holbert, who was Porsche Motorsports at the time did that with several. Heimrath, a Canadian team running TA and IMSA did that to the one I have in 1982.

Then you have the 944 GTR's. These were 100% tube frame, built by Fabcar in the US under contract with Porsche. They ran the 2.5L 8 valve turbocharged motor.

There were odd ones of both he 924 and 944 GTR's made as well. 16 valve head versions in the 924 and 944, etc.

it is all very confusing

[Rasta Monsta]

I would sell the GTR box and build a couple 931 Getrag units.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[MikeJinCO]

Not knowing much about the G31 gearbox I'd tend to go with Rasta. One of those guys with the fully restored $300K GTR's would love to have it. When you switch over to the Audi style box your are going to run into a nightmare of mounting problems to that tube frame due to the differences in attachment of the tranny. In the 944/968 the tranny attaches to the tub, not the banana arms. Plus, where are you going to put the fuel cell? With a standard tub there is not enough room behind any Audi 5 or 6 speed box to put any commercially available fuel cell without getting into the rear deck space-possibly reroute the rear chassis cross tubes? I have pictures of what I had to do to move my 8 gal ATL from behind the Audi 4speed to passenger side above the half shaft to gain 2 inches for a future 5 speed Audi box. It intrudes into the rear compartment space 6", not pretty. Britain Smith made his own fuel tank then had it linered etc shown on his build thread.
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Mike


'67 MG Midget Dp
'71 Ocelot Dsr Kawasaki 1000(under rebuild)

[Carrera RSR]

Can't believe you had two votes for selling a GTR gearbox........not sure what your future view on the car is or what is provenance is, but assuming its the right gearbox for the car, selling it will now for lets say $5-10k will only reduce the value of the car in the future by say $25k+ as the next custodian may want the car nearer to originality? The loss of the GTR engine may impact the car by $50k? Both gearbox and engine may never be replaceable if the car was wanted for period correct racing/use. Just a thought to balance out the sell view.

Making the car useable now is all good and I welcome that. But also keep one eye on what you or the future owner might want of the car. You have said the car has evolved due to racing demands and reg changes etc. But its with you to do the right thing. Its your car, you can do what you want. But in the eyes of the classic car market, collectors and aficionados, originality is king.

I guess its more like the first and second GTR link v's the forth?

https://www.classicdriver.com/en/car/porsche/924/1981/804705

https://www.classicdriver.com/en/car/porsche/924/1981/739081

https://www.classicdriver.com/en/car/porsche/924/1982/745847

https://www.classicdriver.com/en/car/porsche/924/1981/806710
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252

[morghen]

Completely agree with Steve here, i dont see a reason to sell the GTR gearbox...anyhow not sure who would buy it and why.
If you plan to use the car, the best option is to protect the irreplaceable parts and use modern ones instead.
Like the 1.8t engine and some other gearbox, use a conventional TT as well, especially if the car came with the aluminium TT.

Wasnt Mike also making an aluminium TT too?
_________________
Supercharger and EFI kits
https://www.the924.com

[Mike9311]

This is the car as Rasta posted in our member race car section. Scroll down a tad

http://www.924board.org/viewtopic.php?t=42761&postdays=0&postorder=asc&start=15

Box came with the car but I'm pretty sure he is keeping the box. That thing is real $$++. The idea would be to park the trans since its value is only climbing and parts scarce to non-existent

I'm going to help with the tube which for me is a pretty darn cool opportunity and I appreciate you all guiding Scott my way. He is a walking history book connecting these cars and DP's all the way back. Literally part of the story

There are some neat Youtube vids of the car as well. Love how he takes on the modern stuff in this beast. If I find my other links, I'll post
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car

[Mike9311]

http://www.924board.org/viewtopic.php?t=42887&highlight=sanda

Also the DP car mentioned here...

https://rennlist.com/forums/racing-and-drivers-education-forum/1060243-tom-brennans-s-instant-legend-comes-back-to-life-7.html
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1980 931 since 1989
1981 Ideola 931 Club Sport
1982 931 Entwicklungsfahrzeug
1979 924 NA ohne 650 mit 471
1982 931 Red Resurrection - 951 IC
1982 931 parts car / resurrection?
1980 924 NA (R&D lightweight)
1982 931 wana-be GTR race car