Cupcar

Anyone installed the single mass Clubsport flywheel in their GT3?

I note the only difference in list of parts from the kits used in the air-cooled 964 and 993 is the flywheel, the GT3 uses 964.102.239.80 (air-cooled cars use 964.102.239.31), and the clutch plate the GT3 uses 964.102.239.80 (air coolded cars use 964.102.239.31).Otherwise the throw out bearing and guide tube are the same as the air-cooled kit. Is this true?

Any problems?

You like it?

Karl S

GT3 clutch plate is 996.116.015.30 and the cheesehead screws are N 014.715.3. Also with the single mass flywheel, you'll need a starter ring gear which is 964.114.143.31.

Haven't done this mod, don't want the noise and vibration in a street car.

Karl

Cupcar

Interesting, it appears all the parts except the flywheel, pressure plate and driven disc are same as the 964/993 Carrera RS

RR

Karl,

I had a single mass flywheel installed in my 99 C2.
I didn't notice anymore noise, or vibration.

Would the single mass improve engine responsiveness and is it perceptable by the driver?

bob_dallas

A warning though - I think this is essentially the supercup clutch that you get when you do this. I had it put in my old 996 (sans the flywheel) and it was a b*tch to drive. Very grabby clutch. I'm pretty tolerant too but it made the car a pain to drive sometimes - especially in traffic. Sure did grab well - it would bark the tires in 2nd gear.

If anyone thinks the current GT3 clutch is tough, don't even consider this. GT3 is easy to drive...

If you can do it with the current clutch then the result might be different but just a word of warning.

Karl S

Given the reduced weight of the single mass flywheel, the engine will rev more freely. That's the upside. The downside is that it also loses revs more quickly, so you really have to be on your game to get the rev matching done on a downshift. In my Cup car I find I sometimes have to blip the throttle twice to keep the revs up while downshifting (I'm a careful downshifter because it's easy to grab the wrong gear and zing the engine. That's an expensive mistake you don't want to make).

Karl

Cupcar

It looks like the GT3 lightweight flywheel is similar to the one used in the 964 and 993 RS. The 964/993 flywheel is 15.4 pounds lighter than it's dual mass equivalent. This provides better throttle response and slightly faster acceleration.

One down side to the single mass flywheel is increased gear noise. This because the gears are no longer isolated from the periodic accelerations of the crankshaft due to each cylinder firing. This is the reason Porsche installs the dual mass in the first place. The gearbox makes noises like it has rocks in it.

Another down side in 964/993 installations is a poor return to idle when the throttle is dropped, which leads to stalling. This particularly a problem in cars equipped with air conditioning. The 964 and 993 RS cars factory equipped with a single mass flywheel did not have A/C and had a different engine ECU so stalling was not so much of a problem.

The gear noise would still be a result if a single mass flywheel is installed in a GT3, the question is will stalling be an issue, particularly if the car has A/C.

BTW The Cup unsprung 4 puck driven disk is very hard to drive on the street, it works like a switch, better to use the street part with the sprung center if driven on street

RR

Again on my 99 C2,
I had neither, excessive noise problems, clunking problems, nor idle problems.

Cupcar

One thing I should make clear, the extra gearbox noise I described above occurrs ONLY when the car is idleing in neutral with the clutch out. Putting the clutch in stops the noise and there is no extra noise when the car is driven.

Idle and stalling issues may only apply to LWF equipped 964 and 993 cars and not the GT3, as apparently they are not an issue in a LWF equipped normal 996. The question is, is this true with the GT3 as well?

Viken

I had the LWF on my '96 993 and had NO idling or stalling issues. It is the pre-OBDII cars ('95 and before) which have that problem. I doubt that the GT3 will have it too.

Mr. C4

Cupcar,

My Gen. 1 GT3 Clubsport has a the light flywheel from factory and it is actually rather easy to stall while approaching a traffic light or a STOP sign, especially with the AC switched on. PRM's drop really fast so I always give it a blip on the throttle at the same time as pressing the clutch to go to neutral.

And yes, it is very noisy from the transmission and the diffrential but I have learned to live with it by now.

Ciao,

Johannes E.

RR

Ok, please clarify noisy.
Noisy as in ugly noisy or noisy as in gearbox, race car chatter cool noisy.
I'm a young guy, no offence to you old fellows, but I like noisy if it gives the car character..or is the sound just ugly annoying noisy?
Please qualify.

Mr. RS

Race car noisy!! I love it as that, along with the slightly lumpy idle, makes the car seem all the more "Special"

It seems that differant cars make differant noises, some a lot louder than others. It all comes down to personal choice in the end.

P

Cupcar

Regarding the noise, I like the it in the 964 chassis, and I'm an old F***, it makes it more like a Hot Rod so:"I'm there".

Like I said, it is at ONLY at idle with the clutch engaged and neutral selected. Under these conditions you can hear the gear cluster turning and rattleing since there is no load on it-disengaging the clutch will decrease the noise. Once you drive off the noise dissappears so it is really an issue waiting at a stoplight.

The gear rattle is kind of a soft "racka-racka-racka...." noise. It's a race car noise. It is NOT so loud that people immediately upon getting into my car say: "what's that". If you know what it is, you're fine, if you don't, you may think something is wrong.

If you like the car quiet of anything but engine noise when idleing you probably will have an issue with it. It's a love it or hate it thing

The flywheel and clutch can be changed in a 996 without removing the engine, about $600 labor, parts run around $1100 or so for 964 parts (GT3 flywheel may be more?) if you retain the clutch cover. So far reading the posts here, this LWF seems not a bad ~$2000 modification in a GT3, if you wanted a GT3 Clubsport