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GT2 clutch advice


Brick

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Hi all,

After a bit of advice. I am looking to replace the clutch in my 997 GT2. Will be stepping up the power with a tune later in the year, with torque increasing to around 900Nm and power north of 350kw at the wheels. Am also swapping my cats out for a set of 200 cel cats, although leaving the rest of the exhaust stock. In preparation for the increase in power/torque, I intend replacing the clutch.

I am currently looking at retaining the DMFW as I do use it as a road car (not a daily driver) with the odd competitive event (e.g. Racewars). From my time spent researching different options I have narrowed the pressure plate down to a Sachs 88 3082 999 764, which should be good for up to 1000Nm depending on the type of clutch plate. When it comes to the clutch plate I am in a bit of a quandary. As I am staying with the DMFW I do not need a sprung clutch plate, but can I go sintered (e.g. 88 1964 999 838) or should I stay with an organic (e.g. 88 1864 001 098) plate? Or if I go sintered, should I go with a sprung plate even with DMFW?

Has anyone run either of these combinations, and what is your experience regarding clutch take up from stand still, and changing gears? Appreciate any thoughts.

Thanks

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One cannot choose a clutch for someone else. It's all personal preference. 

Going with a pressure plate with more clamp force will put more pressure on your clutch peddle. 
Going with a more coarse friction material will make the clutch feel more "touchy" on/off feel. Also going full face disc is a lot more smoother than a 4 or 6 puck clutch. 

For example when i changed my clutch in my 944 turbo, i have a Sachs Pressure plate. (unsure what one but the clamp force felt the same as oem) and my friction material is a Carbon semi metalic full face disc. this supports my 450whp and 800 or so nm. It feels good, more touchy than the oem but i got use to it. 

In my car, i wouldn't go for a pressure plate with more clamp force as the peddle is hard enough to push. And the clutch fork is known to fatigue a lot with more clamping force to push open. 

 

So if you can afford to have a stiffer peddle then get more clamping force for a smoother engagement feel. But you'd still need to get a more coarse friction plate depending that the pressure plate is capable of with the stock disc. 

 

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Peter Fitzgerald has a client with 700hp 997 GT2 that's done track events, snowy 1000 etc.  so he'd be worth asking.  Probably been there done it.

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Hi all,

After a bit of advice. I am looking to replace the clutch in my 997 GT2. Will be stepping up the power with a tune later in the year, with torque increasing to around 900Nm and power north of 350kw at the wheels. Am also swapping my cats out for a set of 200 cel cats, although leaving the rest of the exhaust stock. In preparation for the increase in power/torque, I intend replacing the clutch.

I am currently looking at retaining the DMFW as I do use it as a road car (not a daily driver) with the odd competitive event (e.g. Racewars). From my time spent researching different options I have narrowed the pressure plate down to a Sachs 88 3082 999 764, which should be good for up to 1000Nm depending on the type of clutch plate. When it comes to the clutch plate I am in a bit of a quandary. As I am staying with the DMFW I do not need a sprung clutch plate, but can I go sintered (e.g. 88 1964 999 838) or should I stay with an organic (e.g. 88 1864 001 098) plate? Or if I go sintered, should I go with a sprung plate even with DMFW?

Has anyone run either of these combinations, and what is your experience regarding clutch take up from stand still, and changing gears? Appreciate any thoughts.

Thanks

Curious as to why you ruled out single mass flywheel (noise, stories of pedal feel put you off?? or both).   

I've purchased a  Bitsa kit (part numbers below) for my 996tt which coincidently is based on the Sachs pressure plate you have quoted (everything else is factory parts) to compliment some other mods.   I thought that Sach's pressure plate is rated at 850nm. .  However I understood that bitsa kit holds its own on a modified 997 gt2 as it does on a non stock 996tt. 

Pentosin Fluid - 1000ML00004330574
Pressure Accumulator99731416600
Pressure Accumulator seal ring99970722440
Sachs 764 clutch pressure plate (88.3082.999.764)883082999764
997GT3RS 4.0 clutch disc 99711601391
964 LWFW96410223931
Flywheel bolts 92810215101
Pilot bearing 93110211100
Throwout bearing 94411608001
Guide tube #395011681330
Guide tube bolts #4 99927007001
Ring gear 96411414331
Pressure plate bolts99951001502
Cross shaft for release bearing fork#595011671004
Gasket 13,02 x 16.4  #699911341840
Articulated Bush #799920133901
Cover #895011672500
Articulated Bush #999920136501
Retaining bracket #1095011671302
Heaxagon Head Bolt M6X16 #1190007505703
Shaft Bush#1295011671501

Also curious as to what brand / size of cats are you looking at running.  Different car, but I ditched the 200 cell cats that was offered with my exhaust and running  a larger diameter set of  100 cell HJS race cats. (just a view, but the incremental cost on 100 cel over 200 cel is not that great and may not see the difference in a peak number, but you may yield a better throttle response across the rev range.

On 997 turbo's hear nothing but good things on the Europipe full setups and note they run an option which has a 100 cels and cat  cross section of ø153mm sport cats is 40% larger than ø130mm cats, 60% larger than ø118mm cats and over 100 % larger than the commonly used ø108mm cats.

 

 

 

 

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Top US engine builder Jake R recommends not using a SMF/LWFW. I had one in my car the performance was great but the risk (for me) was too high (no harmonic dampening, potential burnt clutch, hard to take off, rattling at idol/in neutral etc).

The recommendation on the disk is if you keep your DMF you need a standard un-spring disk if you go SMF you will need a spring disk. As you move up in power an up-rated pressure plate is required.

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On 997 turbo's hear nothing but good things on the Europipe full setups and note they run an option which has a 100 cels and cat  cross section of ø153mm sport cats is 40% larger than ø130mm cats, 60% larger than ø118mm cats and over 100 % larger than the commonly used ø108mm cats.

 

 

 

 

Had a full Akra (exhaust and headers) on GT2 and Europipe "quiet" on the 996, its a fantastic exhaust if you are looking at one for the TT.  

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Thanks for the feedback all.

Re:cats, staying with 200 cel so as still legal but still allow it to breathe a bit better. Am in process of removing and shipping my cats to Canada to get a custom set made using the HJS core. These are the guys making the cats for me www.unobtainiumwelding.com

RE:clutch and SMFW, as I only use the vehicle from time to time for events and spend more time cruising around, the small clutch engagement window was the main concern. Clutch noise was a lesser worry. Just wanting to ensure I have a combination that can hold the increase in torque and power, while still being able to handle normal driving duties (plus the odd fling down a track).

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