Bri Bro

Sure is.

blown 944

Sean, S2 R&P or full S2 trans??? there is a difference in the 5th ratio.

I have dyno'd 145 at 7k and ran that fast in 4th with the 951 trans. The S2 trans to me is great up to ~125 but I don't really like to be powering into 5th at that speed. I guess that is my only problem with it.

My opinion is that a high HP car should stick with the turbo trans. The only reason I am running it is to get the car to feel better w/o having to run crazy boost . So far so good, I have only ran it up to 25 psi.

I won't run it in the other car though b/c I want to crank it up.

333pg333

Sid, both Sean and I have the S2 rp in the 951 tranny. It's generally great in most situations. It could use one extra gear for sure and perhaps 2nd could be a bit longer. That's why I'm thinking of going back to the stock r&p for the new engine, but we may as well try it like this for now.

JET951

ah yes your right we are just using the S2 C&P in the turbo box. i forgot about that one. Patrick may need the turbo C&P back in once the his engine is finished over at PD.
im at the limit of my class at the moment, im allowed either 4 more kw or 10kgs less weight to stay in my class. so the S2 C&P is a benifit for me in that respect.

blown 944

I think that is why he is not troubled with it .
The 5th is .829 (turbo) vs .778 with the s2. The spread seems too far apart for me to like to shift hard into 5th. The RPM's seem to drop too much unless you are fully revved out in 4th. I typically will shift at 6500 and with this combo it drops too much for my liking in 5th.

I think Porsche got it right for high speed but not for around town driving. The best scenario I could see is a 6 spd with a taller R&P. That to me, would work as a good all around setup.

Rogue_Ant

I agree, however I do like my 6-speed box a lot! 5th will still get you ~150mph, and the rpm drop to 6th is much better then the 5-speeds


-Rogue

333pg333

I really like the ratios Sean and I have up to approx. 300 to the wheels. Perhaps more but that's just dyno differences. If I could have a slightly longer 2nd gear in my current setup and a progressive 6th cog I'd be happy. I would say that I'll be hitting rev limit on our long straight with the new motor. We still have the GT2 up our sleeves but that will take a bit of work to fit. Nice option though and looking at those ratios with a high hp / tq motor, I think they look very nice Sean is probably a bit sick of working on my car for now so we'll leave this as is and see what we can come up with.

gt37vgt

I think more about torque than power pat so i think the lower gearing of the S2 and 968 set ups are ideal for the2.5's but too short for a 3.0

333pg333

Yeah I agree but probably a bit of both in reality. Tq down low and hp up top. Thinking the shorter ratios might disadvantage both. As it is I love the quick shifting appeal of it now and I'm sure so does Sean. Guess it will be all relative with the incoming motor showing increase all across the board and therefore probably make the stock gearing feel fine.
Having said all that, I have had this tranny in a previous incarnation of the 3L and it was still fine. Never had it running at full bore though so that could be quite different.

Olli Snellman

I managed to find two 083F ASW versions of S2 trans (thanks to wifes cousin Michael in Solothrun Switzerland). It has hardened 1st & 2nd. Fift gear is longer, 0.778 and final ratio is 3.875. Also differential is stronger than "plain" S2 trans have. Also LSD & cooling are there. This trans was a special order for Swiss market only option.

333pg333

That sounds like yet another great pickup for you Olli. You are very resourceful.

Just to clarify. When you see a final drive ratio, is that an absolute? As in can you compare directly with another one? Does the ratio of the gears themselves not also have a direct bearing on all this? Is there a combination of the two? I don't think so but somehow it seems to me that if you use the two main examples from this thread being the ring and pinions from the stock 951 tranny (.829) and the S2 (.778) it still doesn't take into account different cog ratios. So do we just firstly look at the r&p when comparing gearboxes and then deal with the actual gear ratios?
Does this make sense?

Van

I don't think my car will be ready for the LR race... I'll likely be driving a friend's SP1 car. So you'll be faster!!

blown 944

Pat the total final drive is calculated by multiplying the R&P X the overdrive.

so your final now is 3.212 and the turbo is 2.79.

Josh, it really goes to 150 in 5th??

WOW I am surprised, by the feel of it in 6th on the highway I wouldn't have expected.

Rogue_Ant

Yeah, with a decent tire on the back (275/45ZR17 IIRC), it just makes 150mph in 5th. And much less rpm drop to 6th...

gt37vgt

ooo ge just noticed how silimar my thing will be ...i will be throwing my car together with a k27 and 968 box
ah 45 is that little taller tire is it ?
is that a GPS verified 150mph ?
and at what rpm ?
topped out 6th ? yet