vogel

Has anyone ever tried to place a Corvette C5 tranaxle (transmission and diff) into a P944? I've been doing alot of photo research of the C5 transaxle. Many parts available, gear ratios, etc... and it could handle mucho power.

RedlineMan

Hmmm...

So can a 944 trans. I personally know a guy putting 375 to the rear wheels with no problems in a street car. More to come when the 500hp GT3 car is finished.

The Vette trans is not much different. It's even German. It requires a specialized tool set to rebuild and is probably not cheap from any parameter you'd care to mention. They also have some problems. I have a friend who's box went bad within 5000 miles. No one could fix it, so GM found him a new one and replaced it.

Not sure what the gain would be.

vogel

From my research (mostly Ebay and other peoples strange hybrid and projects cars utilizing the C5 transaxle) i've found that the vette looks promising.

The differential and transmission is two pieces. Getrag diff, Tremec tranny. They almost look as though they were designed with the possiblity of being seperated, or placing the tranny back at the front of the car, if GM ever chose todo so again??? Maybe not.

Anyway, the C5 utilizes a very large aluminum torque tube with the aluminum drive shaft supported on both ends with bearings. Gee, did vette borrow some ideas from the 944, or what?

(BTW, I hear the new RWD Cadillac is going to use the C5 drivetrain, this is promising because it doesn't look like the tranaxle combo will be going away anytime soon, and price will only go down!)

Strangely, on ebay, most of the stuff for sale is seperated, the diff on one sell, the tranny on another. One can buy the tranny, rebuilt and guaranteed for $1750 from rebuilders, the diffs are in various conditions but start at $200 and go up. The most common failure on the diff is the left or driverside ( i believe) output shaft. Probably due to the fact that the case is weaker on that side. A multitude of aftermarket parts are available to remedy this problem. just check the big guy, lingefelter, for some options on new output shafts, case stiffeners, and gear ratio changes... Many other sell upgrades too!

I'm sure i can use the stock 944 torque tube from the bellhousing back, and then modify the transaxle end to accomodate the Tremec. I don't know dimension yet though? will the whole thing fit? how can i hang it?

I'm attracted to the C5 option due to the brutality factor, the gear ratio options, etc... i'm interested in drag/street racing and holding massive power to the ground. I might even go as far as leaving the C5 axles and brakes therfore utilizing the Chevy wheel bolt pattern and being able to run DOT approved street legal drag slicks and good steel wheels.

This is all brainstorming. but i'm building the engine right now. It's being placed in an '83 chasis. I have to have someway to hold the power and this is an option. I'm looking for some good measurements and dimensions for the package to analyze if it will fit. If it can be done, I could build adaptor kits.

I feel the 944 is greatly untapped for it drag ability. As a porsche fan i refuse to set on the side lines and watch 3.0liter supra's make, 650-900 rwhp. I've developed a closed deck design sleeve and i've already taken my engine to 3.0l with the 2.5 liter crank. i could safely go to 3.3 litre with the 3.0litre crank and still have .125 of cylider wall to go larger. by most drag rules, the porsche's four banger is allowed a considerable weight advantage vs. the 6 cylinders which hardly get below 3000lbs. A 944 could be competative with a 1000hp supra, with probably 700hp at 2600-2700lbs.

i'm building a monster.

xoxo,
kevin

RedlineMan

Ummm... yeh...

You would be a wild man!

The thing I'd be worried about LEAST is if it will fit. Body Fabrication is not something I get nervous about!!

special tool

Are you saying that the vette shaft rides in only 2 bearings?????????


Oh, and how can you hang it? Bust out the chop saw, drill press, steel, mig welder etc. - no secret there.

vogel

Well.....

What I'm trying to determine, are some measurements and mounting locations for the C5 transaxle. A good portion of the mystic that the vette rearend holds for me is the fact that it appears very similar to the 944 rearend.

Is it possible that this rearend could be placed in the 944 with minimal mods to the body and stock mounting? Without the measurements it's all guessing, but by the photos, i'm guessing that i could be done.

If i was interested in strictly drag racing, i would simply place a powerglide on the front of the engine and a ford 9' in the back. this is not what i want. I want to maintain the IRS. I want to maintain the the P944 balance ratio. I just want it to handle the power and be reasonable to repair and upgrade.

As for the C5 torque tube. I understand that the tube is large diameter aluminum. Enclosed is an aluminum driveshaft, supported on both ends by support bearings. This is what i've been told by workers at MidAmerica Corvette / Tweeks here in Effingham, IL.

I don't see any reason to not use the current porsche steel torque tube and driveshaft, unless weight savings was desired.

kevin

martin D

Vogel
I just come across this tread so a brief reply that should be basicaly correct !
Ummm.... try same as 928, which was not the 1st car by many years.
The tranny WAS originally designed to be at the front, its used in the Viper, Cobra, Camaro etc.

From disscusions on using a 968 6 speed in the 928 (not possible)it appears that the 944/968 has the diff & axles in front of the g/box. The 928 & C5 have the diff & axles at the rear of the g/box. So to fit a C5 box into a 944, the floor between the rear passenger seats would have to be cut out because thats where the C5 box will sit & not under the trunk floor like you present g/box sits
I hope this helps a little

vogel

thanks Martin!

That's the type of info i'm looking for! Obviously not quite what i wanted to hear concerning the possiblity of body modifications, but still very interesting.

I would imagine that all the different models of cars that utilize the similar 5-6 speed Tremec probably all use different input and output shafts, so the vette Tremec is probably still the one to look for since it's setup for a torque tube and bolts directly into the diff.

thanks,
vogel

vogel

How about a G50 or a 930 turned upside down and put in the 944? Like all the mid engine kit car people (Ultima GTR)? Any ideas if that could be made to work?

kevin

Danno

Here's what I've always wondered. A 968 6-speed tranny is a G50. This is used sometimes on a 944/951. Why not at 911 G50 tranny then?

vogel

Do people make flip gearsets? Or are the tranaxles upside down in one car versus the other? The 968 transaxles have a fair amount of trouble, don't they? Can these problems be remedied and then the transaxle be used in high horsepower 951's?

There are alot of street 951's out there that could be driven harder if the owner had confidence in the transaxle. If this problem could be solved in a reasonable manner, i think it could be a very worthwhile upgrade that some owners would do.

Also, does anyone know what Eddie Bellos did for reinforcing the transaxle his 930 drag car? He was reported making 1200hp on methanol.

Brian Morris

The 968 transaxle is not a G50 - the differential is a G50 diff so they're the exchangable.

The 968 box is stronger than the 951 one. The problem with the 968 boxes is an assembly problem it has nothing to do with the inherent durablility or strength of the box. The pinion was set with too much preload causing premature failure of the pinion bearing. So if this is fixed it's the strongest transaxle for the 944 platform.

--Brian Morris
89 951

Sam Lin

No way you'll build a 944 trans to take the same power a Vette trans will, we're talking 700-900hp at the wheels drag launched on drag radials, hundreds of runs, with the C5 tranny, 375 at the wheels is nothing at all, we do that with the stock tranny all day. The Vette trans is readily available, plenty of mods for it.

Kevin, if you're still researching it, send me an e-mail. It just happens I keep track of the Vette development since I own one.

Sam

vogel

Would you be interested in crawling under there with a digital camera and a tape measure? Tried to find a Haynes Repair manual for a C5, but i guess they don't have them yet??? I could go for a nice drivetrain photo of how the trans is mounted in the vette too. maybe i should track down a vette buyers guide for some factory photos. Seems all the porsche guides have nice photos of the engine, torque tube, and trans.

Jeff Lamb

The problem with this approach is that the axle flanges would be located 3 inches ABOVE the transaxle's input shaft. If you are using a stock ride height and stock tire diameters, the axle angles would be fairly extreme.

I am considering a G50/50 transaxle (mounted upside down) for my 944 turbo road race car that I am building. My car is lowered very extensively (the floor pan is 2" off the ground) and I am running very large rear tires (27.2" in diameter and 14" wide). Therefore, running the G50/50 helps to correct the severe axle angle I have using the stock trans. Plus, the G50/50 is a very strong box (since it is sourced from a 911 Turbo) with a multitude of aftermarket gears and other performance mods.

Jeff