Originally Posted by emmo.84

Looking at the RS 4.0 pressure plate, it seemed reinforced vecause of the triple bands on the perimeter, plus they're bolted and not riveted, I understand the spring is lighter than a 764, and that's what I was looking for, but I can't uderstand the fact that a reinforced pressure plate and new RS 4.0 disk do not hold the torque and power of a 997 GT2...

Maybe they have to 'couple' themselves for perfect contact??

Originally Posted by Kevin

Guys, to shed a little information on the Porsche clutches...

Everything is based off the flywheel. Once you have figured out your flywheel>> three factory choices. Then you can start to build your clutch kit..

The reason why we want to focus on the flywheel "is" it dictates which clutch disk one MUST use. For instance you cannot use the 996GT3 or997GT3 4.0 ltr or GT2RS clutch disk WITH a dual mass flywheel. You cannot install that disk in a 996GT2 or 997GT2. Guy have tried, and then on startup you find yourself not being able to get the car in gear of out of gear.. It is a common mistake.

I'm going to skip the clutch disk options for a moment and jump over to the pressure plates. There are 4 factory Sachs pressure plates that get tossed into the mix. Many internet and parts houses for the last 20 years have opted to insert the 964 NA pressure paired with the 964 RS lightweight flywheel. This has happened for years, on 993TT and 996TT. I still get emails and parts breakdowns with shops trying to install it on 997TT/GT2.. Flat out THAT NA pressure plate will not work. The plate will fail within the first week. I think that there is confusion between the 764 plate and the 964NA car when they look at the RS parts breakdown.

The 2nd plate is the Turbo pressure plate. The plate that leaves the factory 993TT, 996TT, 996GT2, 997TT, and 997GT2... Over the years part numbers have changed, but it is still the factory TURBO plate. It is a bullet proof plate but will NOT hold with a good tune. It is foolish to install this pressure plate when you can get two other factory pressure plates that do a better job.

The 3rd plate is a Sachs Race Motorsports plate with a part number that ends in 752.. This plate is a upgrade over the factory Turbo plate. It is great for the stock turbo 993TT, 996TT, 996GT2 and 997GT2RS.. With the normal bolt on mods this plate works well. BUT will not hold more aggressive tunes and track outings.

The 4th plate and best factory Sachs Race Motorsports plate ends in 764. Toby refers this as the 890Nm unit. It would be easier for newbies to call it the 764/890Nm plate. I can post the physical differences of this plate vs others in another post.. This is really the best choice for a replacement clutch, whether you keep the dual mass flywheel or not.

Warning>> Do not get caught up in the sales marketing STAGED kit numbers.. You can get hosed big time. For the Turbo and GT2/GT2RS owner, make sure you ASK which pressure plate you are getting.. Turbo, 752 or 764.... Call it the Stage Master blaster XYZ.. But in the end get the pressure plate that you want to fit your driving and power output. With that said, the 764 plate can and does fail. Drag strip runs, race track events, and extreme HP outputs will make short life of this plate.

The next topic area is the clutch disks. And over the years Sachs has modified the disks to keep up with better manufacturing and higher torque outputs.. I will make a few blanket statements to clear up some myths.

a) The factory 996GT2 disk is a solid centered NON sprung disk. It has a slight edge in torque rating vs the standard turbo disk (the turbo disk is sprung) the organic lining between the two disks are the same.

b) You cannot install a 996GT2 disk and/or 997GT2 disk with a factory lightweight flywheel. The reason is.. The flywheel is thicker>it is closer to the backwall of the transmission bellhousing. Be careful, standard turbo and GT2 disk can only be paired with the dual mass flywheel.

c) The BEST and strongest clutch disk for track use has been the 996GT3 and new improved 4.0 ltr disk. These disks are sprung to absorb the energy since the lightweight RS flywheel is in place. You cannot use these disk with the dual mass flywheel. They are to tall, and the sprung center doesn't clear the internal cavity between the dual mass and pressure plate. Sachs has redesigned the 997 4.0 disk with smaller diameter springs to reduce the rattle. I favor the 996GT3 disk since the organic lining is the same as the 4.0. The torque output rating is similar. The 4.0 with the new springs can handle more torque at extreme RPM's which our turbo engines don't see.

The last option from Sachs is 4 puck race (bronze) clutch disks. These coupled with the RS LWFW turn street driving into a nightmare. You have to rev the engine to 3500 to 4K to get the car moving. The reason for this disk is because the organic lining just isn't up to the task and heat in racing. One option prior to getting the 4 puck version is to use a aftermarket lining manufactured in Canada. It comes with a 6 puck or 8 puck glass lining and one removes the factory organic from either the Rigid GT2 disk or Preferred GT3 disks. This is the better choice for High Output street cars. Once you smoke these disks, you need to upgrade to twin disk and carbon multi disk systems. Such as Tilton units.

Lastly, like I mentioned in the beginning, the flywheels dictate the clutch choice. It is a flow chart, that has to be explained to your tuner. One clutch kit doesn't fit all the boxes. You could have a stock output 997GT2.. But you race it twice a week in DE or open events. If that is the case I would strongly recommend the RS lightweight flywheel with the 764/890Nm pressure plate and either the 996GT3 clutch disk or 4.0 clutch disk. For tuned engines, I would recommend the same. If the GT2 that gets track is tuned, one can recommend the 8 puck glass lining built on the GT3 disk.

My personal opinion, I don't recommend the factory dual mass when placed into service on the track. I think that the LWFW is better option. Modern tuning today will deal with the previous year stalls and low RPM bucking. The noise or rattle will still be there. But if you have a loud exhaust, who cares.. Shedding 18 lbs of weight pays in the long run. Find a fellow Rennlister to get some seat time in. Please note that many failed LWFW kit have been sold over the years. It is a failure to use any LWFW with a non sprung clutch disk. Many kits come with the GT2 clutch disk. It turns this kit into a nightmare light switch event.

There is a difference between the RS flywheels. The early CUP design is tweaked for production in the 997RS.. The ONLY difference is that it is roughly 2 lbs lighter vs the 964 RS flywheel. 9.2 lbs vs 10.5 to 11.0 lbs. What is different is>> the DME trigger ring is back cut. With the RS flywheel, you have finger for the DME trigger wheel (60 -2) versus solid teeth on the 964 unit. I recommend the 964 RS LWFW.

I have sold hundreds of these kits and no two owners are the same. If you hate the LWFW rattle, go with a dual mass kit. Make sure that you are getting the 764 pressure plate.. FYI, I sell the RS LWFW kit with the 996GT3 clutch disk and 764 pressure plate for $2,295.00 If you want the 4.0 disk it's $200 more.. Feel free to email or call me...

Originally Posted by Kevin

My wife along with Toby's wife can operate the 764 PP. I respect a woman that can "handle" the non sprung disk.

Originally Posted by Kevin

Toby, I knew it... (smile).. As a foot note, you can have the 996GT3RS disk rebuild (relined). The lining can be replaced. It is the disk (springs) that will cause the cement mixer sound. Basically you originally got the holy grail. 1 out of 1000.. Your luck this time might not be as good. BTW, I'd like to "have" that old disk from you.. I would also recommend upgrading to the newer Sachs pressure plate with the bolted cover. It is suppose to be able to handle 1000Nm vs the 890Nm 764 plate.