odurandina

any chance you can slide a 968 box in there and test if it explodes?

TonyG

Don't want a 968 box. It's no stronger than a 951 box and the gear ratios are much too close together for a car that has a wide fat TQ curve.

TonyG

Duke

How this would fit on a stock length torque tube is a mystery... unless you want to increase your wheelbase by 20 inches

V2Rocket

the nice thing about our driveline is that its easy to change length!

check this out, i posted a thread/link a few days ago...944 trans/tube mated to 911 engine, in a VW van..

333pg333

How difficult would it be to modify the TTube though?

Duke

Possible but you will need to cut up the floor and back seat area to fit the front of the transmission.

You might as well look into fitting the Corvette torque tube as well as it's in aluminium and lighter than the 944/968.

odurandina

it was a question offered in jest....

I surmise you're in 3rd, 4th and 5th 98% of the time, and it's well known the ratios on the '68 box are all but useless for racing a v8...

still, I'd love to see if it would break from your regular driving.

xschop

From experience, My C5 6-speed trans and torque tube is 78.375" from axle centers to BH mating face....
944 is....77.18"
I have built a few sets of axles for the 928 6 speed swap, including my own 1GZFE V12 project and the outboard 944 stubshafts would only need a set of CV adapters. A couple members on hybrids (Kevin924Kevin comes to mind) have done the swap using thefactory steel torsion tube. It needs to be chopped and "horseshoed" while removing torsion bars and adding coilovers. Or similar to Tony's build here the torsion tube can be tossed for a double wishbone suspension. Lots of work but well worth the effort. The carbon synchros are smooth as butter and even a supercharged V8 wont pop anything on a stock box. Not to mention the F1 weight distribution when the heavier weight is transfered to back.

333pg333

Well yes, that would be even better. Pretty sure one guy did this sometime ago. Steve Rea comes to mind? I think Tony remembers him and suggested that he had issues chasing roll centres etc but to me it's a good concept for race cars that can be cut and fabbed.

People jest at the 968 gearing but I don't think it's all that bad. Of course for a V8 it's not ideal but both Duke and myself run 3L + motors that have pretty decent torque and have the 6 speed with stock gearing. Hasn't hurt us as much as some would theorise.

You should do a thread on this stuff. Especially your V12 conversion!

TonyG

The bigger issue is the floor pan of the car. You'd have to chop a large portion of the rear tunnel away to make room since the Vette transaxle is so much longer.

But the Vette guys break these transaxles too. I see quite a few of them being replaced on race cars at the shop that does my GM engine work.

If you're out there drag racing the car.... I don't care what transaxle you use, it's gonna break.


TonyG

TonyG

I'm in 3rd, 4th, and 5th 100% of the time unless I'm in the pits.

1st and 2nd gears are a part of the input shaft and the gears are just to small to handle considerable torque.

That said, the only 951 transmissions I've blown since 2006 on the race track are two.

1. The stock LSD case split in three pieces (these pieces are welded together) which moved the ring gear and took out the pinion gear and more. This can't happen with a Guard LSD.

and

2. Took out 2nd gear at Laguna Seca. I knew not to use it and I did. So it's no surprise that it stripped the teeth off 2nd gear.

So with a big TQ V8 and the fact that you can run the car competitively in 3,4,5 gears, why bother with a Vette transaxle?

As far as axles go, I run 996TT axles and CV's. The only thing that's modified is the transaxle stub axles being machined and drilled for the larger 996TT CV bolts, and using BoxterS outter CV races on the tranaxle side. This setup is known to be "bullet proof" on the super high 996/997/Cup race cars.

TonyG

333pg333

My interest in a Corvette setup would be to include the suspension, not just the gearbox. While your build and Dukes with not dissimilar suspension is fantastic, ideally if you were to go with a blank sheet of paper you'd want suspension with longer arms/levers than a rear engine Porsche can fit. Might be being picky but the longer levers should keep the wheel in a more vertical state for more of the time compared to the shorter Cup levers. Of course the Cup suspension has had a zillion dollars spent on it over the years in terms of R&D but you'd also think that there would be a fair bit of time spent on the Vette rear end. Plus assume parts would be considerably cheaper. Overall a full Sequential gearbox would be better still but there's a limit to expenditure and one has to examine R.O.I. before making such leaps!

TonyG

The guy that used the Vette transaxle used the Vette rear suspension too.

It never worked out. The roll centers were all wrong. The car had to be run up high in the rear to make it turn properly.... which it never really did.

I'll post pictures soon.

TonyG

V2Rocket

i can understand the longer arm = more vertical tire on a swing axle but with upper/lower unequal-length links is there really much more to gain?

333pg333

Yeah I remember that guy. In fact he was selling his car some years back and it was a good deal. Don't see why they couldn't sort the roll centres out properly though?

I'm probably looking at it too basically but I'd still think longer = better in theory.