944S2, Turbo or 01E Trans

So, I sheared the input shaft of my bastardised 944 S2 (3L Motor version) tansmission the other day. It lasted 5 years of hard competition work, so can't complain really. Was hoping it was clutch splines that went, but no luck...

So, ideally I want a 944 S2 input shaft. I can then get that machined and splined to work with a clutch and off we go again.

Failing that, I guess a complete 944 S2 trans, though may consider a 944 turbo trans. They are basically the same thing, but turbo has a taller final drive, which I'm not sure I want.

Also may consider an 01E 6 speed, as I know they can be adapted to my current setup with different clutch, flywheel etc. Bit more work needed, but I guess nothing is easy!

Come at me with what you have. I'm in Western Australia, so nowhere near you no doubt...
 
Well, dyno figures don't mean much but it's a healthy 347, 440 RWHP, revs to 7000, and does 125 MPH over the 1/4 mile in a DRB. So that should give you some idea.

If you want to see what it puts up with, youtube 200MPHGT40. The last event (rallysprint) is where it sheared on the 3rd run changing into 3rd gear.

Basically I had a 944 input shaft machined down to fit the 016 clutch plate, and that's where the splines twisted and sheared.

I know I can fix anything with enough money, but that is something I just don't have at this stage of life! And I want to get on with racing, hence probably have to do the same again. Get an input shaft, tweak it and try again.
 
Hi Julian, I have a 016 std diesel box in my project and the clutch company used a Mazda rx7 mk4 pressure plate and a suitable clutch disc and they fitted a suitable centre spine section so there was no need to reduce the Input shaft, only mod was a 3mm skim out of the belhousing to accept the Mazda pressure plate but I don't think a an 016 would hold 440hp for long lol
 

flatchat(Chris)

Supporter
Well, you've had a good run out of that Trans for sure
As Lambo says it is easy to have the clutch plate re hubbed to suit the input shaft than machine the input shaft
FYI -- the 016 PITA has a 20 mm OD 24 spline input and 18 mm dia spigot
The 01E, 012 , G86 etc have a 24mm OD 23 spline input with 15mm dia spigot

So, cheapest way out for you now is - install a new input shaft unmolested and re hub the clutch plate to suit and you're away-- assuming the 944 is a 24dia 23 spline job-- the 23 spline is fairly common - ford, VW etc
9" / 240mm dia pressure plate is about max for that bell housing
 
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Yeah, I've found a couple of sources of 083 trans input shafts in Australia at reasonable prices, including one local to me from a Porsche specialist who I've got stuff from before. So will go see what diameter I can reasonably spline onto the shaft to take a common clutch disc. I just need to find one that's about the same thickness and is 240 diameter like my existing setup from KEP. So far the obvious choices seem to be Silvia/Skyline/Commodore 3L VL 240 mm or Mazda RX-7 S4/S5 13BT clutch plates. Any of those are plentiful and easily purchased in various grades of bite. I'll go for a fairly standard friction plate as per before to cushion shock loads on the trans. The KEP pressure plate is heavy (measured at 1 tonne clamp force) so the clutch never slips.

Chris - I can't really use the existing Porsche splines. Well, I don't think so. Be great if I could and just had to shorten shaft to suit and machine down spigot on the end, much cheaper! The splines are proud of the shaft and don't extend back far enough away from the pressure plate to work. So have to cut splines into the shaft, the diameter is yet to be measured, but apparently it's around 25 mm. So that will also determine what friction plate to use and then give to the spline machinist as a go/no-go gauge.

Will get input shaft cryo treated locally too once modified, just to give it the best chance of a short and hard life!

Anyways, first to strip gearbox down enough to decide if it's all OK inside still. If it is, then I'll just give it new 1-2 synchros, which are getting slow and baulky to shift. Seems a happy trans otherwise, before the shaft cried enough that is!
 
Oh, and Graeme - no, an 016 does not last long behind my motor. About a year of shakedown completion events and the diff pinion sheared a few teeth and we ground to a halt. I've posted the results of that little misadventure back about 6 years ago when it happened. Wow, time flies, and this bastardised 016 front housing and 083 trans has really done well. I've gone through a pressure plate or two since then, and some busted trans mounts, but it's done me very well.

Ideally a Porsche 968 version of an 01E would be good. Much nicer close ratios, but the expense of buying one and then doing all this input shaft malarkey makes me thing thrice. They do however have the common Porsche G50 diff centre fitted, unlike the 01E, which opens up cheaper and more plentiful LSD options. So that saving makes up in part for the additional purchase price.

But I can't see myself getting it working in the car for under A$5-6k however. Maybe an 01E with the crappy diesel ratios they seem to come with, and then get some 968 3-6 gear ratios swapped over if/when I have the cash. Nah, that's dreaming, but it's not a bad idea in theory.
 
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