911racer

I know that what I want for my 86 944 Cup race car is to add a LSD and the 5th gear from the later transmissions.

The question I have is, what later transmission can I get that 5th gear from.

When did Porsche start using the shorter 5th gear.

I have heard that the 951's had a completely different gearset that is taller than the NA cars.

What about the S2's, did they have the same gears as the NA or the turbo. And if they are the same as the NA cars, did they have the shorter 5th too?

Thanks

Ed

Sterling Doc

951's have the correct 5th, all the rest of the ratio's are off. 924S's have the correct ratios, as do '88 944 N/A's. 944S's have the correct 5th but all the other ratios are wrong again.

schwank

I got a 87 924S transmission and installed a Guard LSD in it.

Listen to the Doc... he's got you covered.

Fast82930

This would be the 0.8286 / 35:29 5th gear.

Lyall
82 930, 2500lbs 430hp, Black | 85.5 944 Cup / ITS / PCA4 racer, Black
87 Carrera, stock, GP White
00 Audi S4 - 340hp, Imola Yellow
03 Boxster S, GP White

schwank

What's up Lyall?! Can't wait to get out on track this year. Hope you are ready... we'll see you soon!

Fast82930

Hey Eric,

I'm looking forward to the new season as well. The 944 is at Fordahls for alignment/CB and a few other things. I also purged the pig of more fat to help erase the work some of the others have done over the winter

Lyall
82 930, 2500lbs 430hp, Black | 85.5 944 Cup / ITS / PCA4 racer, Black
87 Carrera, stock, GP White
00 Audi S4 - 340hp, Imola Yellow
03 Boxster S, GP White

UncleMaz

Actually, a 944s has the same gearing as a 951, except the S has a short fifth gear.

Edit: and the same final drive as an NA/8V

911racer

Actually, I ran across the clarks garage info.

It would appear that the 944S is extreemly close to the 944. Same FDR, just slightly different gearsets. Only about a 3% different than the NA 944 (and that is all in how tall 1st gear is, the rest of the steps are the same jump)

I would agree that the Turbo S is the same as the Turbo, but the 944S trans (the AGR trans) is very close to good.

Unless I am missing something.

http://www.clarks-garage.com/shop-manual/trans-04.htm

Thanks

Ed

Oddjob

87-88 924S and I believe the 88-89 944 N/A come with the short 5th (0.829), pretty sure all previous US 944 N/A transmissions have the tall 0.730 5th.

The 944S has the same gears as a Turbo (both have an 0.829 5th but are not the same part number as the N/A short 5th), but the S has the short 3.889 R/P (same ratio as the N/A, but different parts) instead of the Turbo's 3.375. The S2 trans has the same 1-4th as the S and Turbo, and a 0.778 5th w/ a 3.875 R/P.

I have heard that any 0.829 5th can be installed in an N/A trans.

Mike Buck

What final drive are you using Ed, stock? Think the local guys here in the Mid-Atlantic run a 4.xx unit from an Audi something or other. I have a hard time pulling them, even with my 'at the hp limit' 944 TS

911racer

Well, legally speaking. I am running in the stock class, not prepared, so the 944 cup rules say that you can update or back date, but you can not use any gears or combination that did not come on the 944's.

Under prepared, I can change the final drive ratio.

Would be interesting to hear what they are getting it from.

schwank

The short 5th is allowed through update/backdate. Also some cars came factory LSD so that is allowed, and it goes one step further to say ANY LSD.

An Audi R&P can be installed, I think from a 4000. But I also think it is too long for a stockish 944 8v motor based on the applications I've seen. And as noted, not a Cup stock class legal item. Also could not be run in SCCA ITS and likely other orgs like PCA4 anyway.

LSD is painful regardless. I bought a used factory trans for my 951 and that was not cheap, and if you factor in a likely rebuild on the stock unit it is even more. On the flip side I just got the bill for my new Cup car trans - 87 924S rebuilt with Guard LSD and... UGH. I'm gonna need to skip the sushi and eat pasta for a while!

comatb

"Legally speaking" the 944 S transmission is not legal in Cup, because as noted above the ratios are not the same. Yes you can take the 5th gear and install it in you transmission, but unless you are running a 944 S in Super Cup the complete unit is not legal.