clubsport1

I am not aware of any other engine / transmission differences between the M002 and M03 versions, but as I said having owned both there is definitely a difference to be felt when changing from 5th to 6th.

Have you ever driven a regular 993 RS and genuine CS back to back?....did you notice any difference?
If not I would reccomend it, internet banter is all very well

I doubt anyone would pay the CS premium purely for the gear ratios alone, the G50/32 is a relatively small part of the overall appeal of the Clubsport

Jean

So the difference certainly is not gearbox related, or is it?
Think about 220lbs weight reduction on the CS and their impact on your perceived acceleration.

We can chat about my driving experiences in a such related thread, just wanted to point out the inaccuracy in your statements.

Geoffrey

If it were me, I would select my top speed in 6th that I will use on a track at your redline and work the gears backwards from that. I might suggest a 160mph @ 7000rpm with a 25.3" diameter tire. I'd replace 3,4,5,6 and possibly 2nd if your car has an early gearbox where 2nd can be replaced. You'll also want steel syncros on at least 3,4,5,6, and you may consider the 3/4 motorsport shift fork which is steel rather than aluminum and will wear better. You'd need to price this out as it may be less expensive to buy a gearbox. Personally, I think that the G50/31 6th is too tall and the RPM drop from 5th to 6th is way too large as is 4th to 5th. There is so much aero drag on the car at those speeds that the torque drop is too much.

I would also tend to agree with Jean that it is probably the weight more than the small gear differences that you notice between the RS and RSCS at those speeds.

clubsport1

Thankyou, you are more than kind to have taken the trouble


Any idea why Porsche would bother to put different ratios in 31 & 32 boxes if there is such a small difference in actual use?

With respect to accuracy a CS with the full matter cage, doesn't really weigh any less than a basic non optioned standard RS, so I am not so sure weight makes up so much difference in higher end acceleration patterns.

maurice97C2S

I've been around circuits in both Paul's RS's, and the clubsport definitely has much closer gearing .. compared to my /20 it is poles apart, whereas the 'normal' RS was not dramatically different .. can't be sure it's standard .. any idea, Paul ?

cheers, Maurice

Bill Verburg

As mentioned the syncros and shift forks are more robust on /30 and /32 vs /32 or /21 or /20

The shift to 6 actually has a larger &% drop on the /32 than on the /31 because of the 5th gear ratios
here are a couple of ways to look at them in comparison

N51

Geoffrey,

Good thoughts, and I agree with your assessment. I chose the /31 box based on my needs.(no track). If otherwise, I'd gone with Bill's /30.

Noah

Geoffrey

The other issue to realize is the strength of the gears selected. With the 3.44R&P, as you select shorter gears, they become weaker compared to the amount of torque they provide. If you use a 4.0R&P like most of the racing gearboxes (ie RSR), the gears are not as short and are stronger. Further, Guard Gears produce gears that are thicker and therefore, stronger, particularly for 3rd gear which is the most used gear and often the gear that breaks when a gearset breaks.

clubsport1

Maurice, car is totally standard, even had a factory gearbox rebuild when new under warranty with all parts listed seem to be in order....

Back to the original question of gearing,,,I drove a car last year fitted with an 8/32 ratio crown & pinion,,,,the gearing felt way higher and 5th gear acceleration was very strong. has anyone fitted such a final drive to a US 993?

Assuming their were drive benefits, i would also expect this to be more cost effective than switching transmissions.

Geoffrey

Simply replacing the R&P does not alter the gear spacing which is the major problem with the gearboxes from a performance perspective. I have an 8:32 R&P in my 97 C4 box (converted to 2wd) along with different gears, 996RS LSD, steel syncros, motorsport shift forks, and a transmission cooler.

Jean

Geoffrey is correct , there will be no difference in RPM drops between gears with either R&P.

However with the 8:32 R&P your gear ratios will be about 16% shorter, so you will have 16% more Thrust and acceleration within each gear and 16% less top speed in each gear.

clubsport1

That is roughly what I was thinking,,,,maybe the impression of 16% more power?

Has anyone done this with standard US gearing, assuming it is tolerable it has to make sense from the $$$ point of view....how often do we Vmax our cars in 6th even on track?

Bill Verburg

As noted just dropping the cwp ratio to 4:1 still leaves the big irregular drops
Stock /20


Stock /20 w/ 4:1 cwp


proper box

N51

Can anyone make a recommendation, one way or another, in regard to using a friction modifier(FM) with the PMS LSD?

Sorry to go off-topic.
Noah

Geoffrey

In these gearboxes you should be using Mobil 1 Delvac synthetic 75w/90. This is the rebranded mobilube SHC gear oil. Do not use the store brand Mobil 1 75w/90, and do not use a friction modifier. Both of which make the syncros too slippery and they do not grab the gears properly. Ask me how I know? I ran both and the Mobil 1 Delvac is a better oil, and is the oil Porsche uses in the Cup and RSRs shipping these days. I also ruined 3rd gear and syncro with the store brand Mobil 1 75w/90 on my race car 6spd. There may be other oils that will work, however, I know the Delvac works.