JayP

Thanks guys- I'll put the word out that I want a later model NA transmission. The local 944 breaker has just the one turbo unit left. I'll put him out to look for another transmission.

I hadn't realized the difference in the final drive was that significant. I don't need another reason to be s-l-o-w on track.

josephsc

Since this is a track car, you definitely want to find something with a short 5th gear. I just re-viewed your transmission death video and you're currently using the 5th. So.... my recommendations would be

* find a S tranny
* find an na tranny from an '88 (maybe an 89 as well?)
* find a 85.5-87 na tranny and swap out the 5th gear from a turbo tranny

M758

Well the "S" tranny that Jay busted should have a "short 5th" in it. Get a regualar long 5th NA box and put the short 5th from the busted S box. My guess is that your 5th would be good shape even the R&P is busted.

I think you wan the 35:29 gear pair for the short 5ht (0.829) vs a 37:27 for the long 5th (0.727)

JayP

Texas Motor is an exception. I was getting to 120 on the straight and that was a half lap to get there! The other tracks I run, I won't have that type of runway.

I liked having the tall 5th- I was probably getting 25-30mpg on the tollway at 75mph.

M758

944 Gearbox Chart

............... 82-87....... 88-89....... 944S.........951
F/D...........3.889........3.889........3.889........3.375
1st............3.600........3.600........3.500........3.500
2nd...........2.125........2.125........2.059........2.059
3rd............1.458........1.458........1.400........1.400
4th............1.071........1.071........1.034........1.034
5th............0.730........0.829........0.829........0.829

Jay per this chart you currnet 5th gear ratio would get taller with 8v gearbox. You already had the short 5th. The 8v gearbox would give you a few more RPM in 2nd 3rd & 4th.

TT

Here's a spreadsheet with all the info:

924.org Transmissions

944J

I read somewhere that its just a myth about the inherint strength of the turbo transmissions. no first hand knowledge here just saying what I read from someone online who rebuilds them...

(btw my na trans 2nd gear is gone!)

whalebird

fwiw, I've heard the porsche924 turbo trans was stronger than any of the audi units. stage 2/3 944 turbos can twist the pressed - on third gear off the shaft with copius street use. I could be wrong though, I know some fast turbos with the original trannys well over 200k miles.

Robby

Joe- you said " You already had the short 5th. The 8v gearbox would give you a few more RPM in 2nd 3rd & 4th." Actually, all the gears are exactly the same, so going to the turbo gearbox would change each & every gear- fewer rpms in each gear, taller gears, whatever... is this what you meant?

tifosiman

No myth. The turbo trans is stronger.

Robby

Whalebird- you mentioned that about the 924 units being stronger than 951's- Windward had that on their website a long time ago- they said that 924 units were made by Audi & were stronger than 951 units- I've never seen or heard it anywhere else though & most people say it's BS- I don't believe it. Evidently, the 968 trannys are strongest of all- Jon Milledge uses them in is higher HP applications- Powerhaus says the 968 gears are weaker- I'd trust Milledge over anyone for that type of stuff though...

M758

I was talking 944S vs 944 NV 8valve.

with respect to the 924 trany. There is version may by Porsche called the 'snail shell' I believe that is the "stronger" on they refer too.

924RACR would know.