jchaley

I installed a S2 tranny in my turbo this weekend. My reason for doing this was to improve off boost acceleration. I live in Denver 5000+ ft elevation and the off boost power and turbo spool up are really bad. I had already tried boost enhacers and shimmed the waste gate. So far I love the results. The best way to describe is that it is like 300lbs have been removed from the car. Much easier to pull a way from a dead stop with out the engine lugging. With the shorter gears I find myself using more RPM. Once moving the spacing and RPM drop between gears is much less so I am always in the sweet spot. This is a great street set up and would be good for short tracks. With my snow tires it is easy to break the rears loose in 1st gear, and not that hard in second(i really had to work at this with the stock tranny). The only thing I am not crazy about is the short 5th gear. I wish that 5th was taller, but since most of my driving is around town it is not that big a deal (acceleration in 5th at highway speeds is outstanding). If I lived at sea level I probably would not have done this mod but it works great in Denver.

John

See my other post for my stock tranny for sale 86 with cooler and limited slip.

wjk_glynn

Interesting. I've also heard that 968 tranny's work very well with 951's.

Karl.

Maciek

John,
Did this take any kind of modifications? Did you use the turbo drive shaft? Did the tranny just bolt right up? I am putting a 951 engine in my S2 cab, and I will be changing the tranny eventually, but I would like to know what is involved. Thanks!

ian

Maciek,

The S2 and 951 tranny a very similar, both inside and out. And they will swap from one car to the other with any issues (minus the PTA that it is to get the tranny out of the car).

The 968 Tranny will bolt up as well, but you loose use of the speedo. If you don't care about breaking them even the earlier ones will fit in the car, someone on the board had a S tranny in a 951 not too long ago....

Maciek

Ian,
Thanks, I knew they were the same tranny except for gearing, but the question was asked earlier by others without any definite results. I figure I would ask since John had tried it. I will eventually swap to the correct 951 tranny due to the cooler and it has LSD but if I can put it off for a bit it will let me get the car on the road quicker. Thanks again!

Waterguy

John, that swap makes alot of sense for you if you stick with stock 951 power. The only differences between an S2 transmission and a 951 transmission are a taller fifth gear and a shorter final drive. That gives you lower gearing 1st thru 4th, but a tall enough 5th to still hit almost 150 mph (should you want to.) You wouldn't gain much on paper (e.g. 0-60, 1/4 mile times) because you will have to shift an extra time (60 mph in third gear, 1/4 mile in fourth), but it should really help in the real world of everyday driving.

With that lower first gear, you may want to think about getting LSD for the S2 transmission; you will need it even more than you did before.

toddk911

Possible to switch to S2 or 968 clutch/PP? with out heavy mods?

jchaley

Well the tranny swap was very easy. Remove old tranny 3 hours (the cooler makes this much harder and I had not done this before) bolt new tranny in place (much easier with out cooler in the way) 1 hour. Go for drive. The S2 tranny gearing works much better than the stock turbo tranny. I love the shorter first gear and the closer ratios would not mind a taller 5th. Over all a 3 on difficulty and a 9 on happiness with results.

Waterguy

In an earlier post, Danno figured that you could swap the taller 0.73:1 5th gears out of an 85.5 to 87 944N/A tranny into a turbo tranny in about 2 hours. Should be the same effort for the 944S2 tranny. That would give you a virtually identical 5th gear ratio to the 951 transmission (2.83:1 overall versus 2.80:1 overall for the stock 951 tranny 5th gear.) Definitely would not be a 3 on the difficulty scale, though.

Hey, you could add LSD at the same time....

Tom Pultz

</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by toddk911:
<strong>Possible to switch to S2 or 968 clutch/PP? with out heavy mods?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">Not sure why you'd want to do that. The S2 clutch is 225 mm and the 951 and 968 clutches are 240 mm diameter. They are all very different in design. The stock S2 is rubber center, the 951 spring center and the 968 solid center (for use with the dual mass flywheel). None of these parts are interchangeable and the sensor pickups are different too.

jchaley

The NA 944 5th gear might be interesting I will have to look into it further. I have rebuilt a couple 915 trannys for 911,s so I would be willing to think about a gear swap in the S@ tranny. The tranny I installed already has limited slip. I did not want a open differential because I drive the car in the snow (plus I have some power improvements planed so it will not hurt in the dry either)

john