New clutch required?
 

I got my first clutch slip today in 6th gear with an ambient temperature of 7 degC. I floored it with over-boost off (1.0 bar) from about 50 mph. I couldn’t get it to do it again even with overboost (1.2 bar) in 5th gear downwards.

I can still smell the burnt clutch an hour of driving after it happened.

Does this mean I need a new clutch or is one clutch slip no big deal? Saying that, I did have a similar thing reversing up a steep hill back in 2008 in Switzerland, the smell lasted for about 20 mins then.

I know I have 798Nm torque with my CG544 kit which exceeds the factory clutch tolerances; perhaps I need a whole upgraded clutch kit?

Eg. Cargraphic Clutch

Or perhaps just an upgraded pressure plate?

My car only has 17k miles on the clock so I would rather not change the whole clutch out unless I really need to.

Would appreciate your thoughts...

(also opinions on single mass flywheels please as part of that kit mentioned above)

It's time for the real deal. You need a clutch with more clamping force.

I used to get this in my 996tt and the clutch never did go, it happend about 6 times over the time frame of about 3 years and always happend on the motorway in 6th gear! (i did ask my porsche mechanic about this too and he said it could be due to the fact the plate is not warmed up properly yet and the surface might be smooth at the point that it slipped?)

If your clutch was really gone it would not bite at all and just fly up the rev range without your car going anywhere.

Just keep an eye on it as you never know!

Have a sachs plate sitting there ready and waiting or you could with a lightwieght fly wheel kit as this would help with performance but im not sure about it for a daily drive although some others could advise you on this.

P.S. My old 996tt had exhaust and remap and i got it with 24k miles and sold it with 50k miles and clutch was still fine as I never launched it.

Alex, I'd bet it isn't the clutch. It's the pressure plate. You need something with more clamping force. Unfortunately, the cost of labor is the same, so you'll probably end up doing both. You could do a standard Sachs 2 upgrade for the power level you are at. If you plan on making more power later, spend a little more and go to Sachs 883082 999764.

Thanks for your thoughts guys. That kit I linked to in my OP looks like a Sachs kit to me with a 890Nm pressure plate.

http://www.cargraphic.de/stepone/dat.../PO502a_gr.jpg

Single mass flywheel is what I am debating. Apart from the rattling on idle, does it make for a better driving experience?

Alex, I use an Aasco aluminum flywheel with a Sachs 2 setup. Here are the pros:

1. Noticable ease in rev matching/heel toe shifting.
2. Noticable improvement in acceleration in 1st and 2nd gear.

Cons:

1. Rattle. The rattle can not be heard when you first start up and the engine/transmission is cold. As it warms up in neutral, you start to hear it. When you push the Sports Chrono button, the idle changes, and the sound goes away again. If you start the A/C, even with Sports Chrono, it is noticable, (a la GT3 RS.)

2. Low gear/WOT noise. The Sachs clutch is unsprung...meaning it does not dampen anything from the engine. Under WOT 2000-3000 RPM in a higher gear (ie you are lugging the engine) you will hear rattle.

This setup (Aasco/Sachs 2) is the same as what AWE used. They can also give a pretty good analysis. They ultimately removed the flywheel because some customers were confused by the noises.

Alternatively, you could go with a different setup...Clutchmasters makes a very good setup with a LWFW which apparently is noise free, although some have commented about the very high engagement point of the clutch.

- bob

Another note. I'd definately checkout the setup before you get it installed. Otherwise, you'll be paying for another 10 hours of labor to remove it. :)

There is unfortunately no such thing as a compeltely noiseless LWFW...by definition, the LWFW will allow transmission of engine pulses/noises to the transmission. There have been a few who have swapped transmission fluids to something thicker (Redline Shockproof) but I'm not sure what the safety is over Mobil1 Delvac.

A wealth of knowledge, thanks Bob!

AWE's offering:
http://www.awe-tuning.com/pages/shar...n&IL=996stage2

Looks like a stage2 would be enough. I will try to find out what the Cargraphic kit consists of exactly.

Bob/Alex, thanks for the very helpful thread.
Bob, I would most likely get mine from AWE; on the page that Alex quoted above http://www.awe-tuning.com/pages/shar...n&IL=996stage2

Yours would be the first one on the table: <TABLE border=0 cellSpacing=1 cellPadding=0 width=585><TBODY><TR bgColor=#cccccc><TD>Sachs/A.W.E. St2.5 Clutch Kit w/ LW Flywheel (996T </TD><TD style="TEXT-ALIGN: right; PADDING-RIGHT: 2px">$2,625.95 </TD></TR></TBODY></TABLE>

And if I don't want the flywheel, I would get the second one listed on that table? Would this be the one that feels most like stock? TIA.

<TABLE border=0 cellSpacing=1 cellPadding=0 width=585><TBODY><TR bgColor=#999999><TD>Sachs/A.W.E. St2.5 Clutch: 996T/GT2/GT3, 997T </TD><TD style="TEXT-ALIGN: right; PADDING-RIGHT: 2px">$1,530.95</TD></TR></TBODY></TABLE>

Hi Cannga...

Mike or Todd will be able to tell you for sure, but I think Gene had reported a very stock feeling clutch pressure and engagement using his stock OEM dual mass flywheel with a Sach's 2, and the upgraded pressure plate (part #883082 999764) hence Sach's 2.5 not 2... :)

The Aasco flywheel feels pretty similar, but in a direct comparison, the engagement point is higher than with the OEM dual mass. The engagement range is pretty similar.

Bob,

I changed my setup to a Clutch Masters this week. The LWFW rattle is the same as the Sachs setup. You are correct on the engagement point. It is slithgly higher than stock or the Sachs setup. I've already stalled it a fews times.. hilarious



Alex,

I had the Sachs stage 2 setup with the AASCO LWFW. It lasted about 7500 miles before it slipped. This setup is rated for about 540-550 ft lb of torque. I think you might want to look at the Clutch Masters setup. It is supposed to hold over 800hp with no problems. 2/20-934HRF-AL is the part#. $3225 retail. It comes with an organic/fiber tough disc with a pressure plate rated at 3900lbs of clamping force and a LWFW. If you want to keep the stock drivability, you need to stay with the organic/fiber tough combo.

Do you know the clamping force with that upgraded pressure plate? Sach's website doesn't give any real specifics.

Thanks.

PS: I feel like I should rep you on almost every message you post. Always most helpful info.

Thanks. Below is a table from Sachs showing the rating of the 2 pressure plates, I assume one is of the stage 2 xxxxx752 (torque rating 544 lb-ft with organic disc), and the other one which Gene upgraded to, xxxxx764 (rating 659 lb-ft).

It seems from reading Gene's post https://www.6speedonline.com/forums/...utch-feel.html , he re-used the OEM clutch disc (as opposed to using Sachs xxxxx973)? Is that possible?

Mike, which pressure plate did you use that didn't hold up with your stage 2, xxxx752 or xxxx764?

http://i214.photobucket.com/albums/c...tecopycrop.jpg

Cannga's got the data sheet. If you want to rep someone, Cannga has data comming out of his ears!

I'd + rep for a very useful table, but I guess I need to spread it around before I can hit him again, lol!

bob