[arawson]

I've recently upgraded my M95 9000 Aero to Map Tun stage 1 (420mn) and I'm now experiencing clutch slip in 3rd, 4th and 5th when accelerating in the 3-4k rpm band. My clutch/ slave cylinder is about 18 months/ 20k miles old and was fitted by a Saab dealer when I had my gearbox rebuilt. I also had the clutch pipe replaced last year.

Has anyone experienced this with this level of torque and, if so, what was the solution?

I’ve read a couple of old posts that mention a Sachs Comp pressure plate (expensive) and an AP Racing driven plate (judder/ eats flywheel). Are there any other choices?

Does anyone know what size a standard 9000 Aero clutch is and what torque it can handle?

Any advice will be greatly appreciated.

 

[peter messenger]

i had the same problem on a 9000 lpt maptun stage 3 370nm.
i have just had a new clutch/fly wheel skim.
parts used were standard saab, i did not want the aggresive paddle clutch, i have been told several times that the standard clutch should cope. and at the moment it is.

 

[ylee coyote]

it can be a problem but as peter says the standard clutch should be ok... up to a stage 5 !! my car was putting out 316 ft/lbs (440 N/m) of torque and I never saw clutch slip.
however there has been a couple of guys on here that have fitted the ap paddle and have found it ok
I have plumped for the sachs option myself
I will let you know what its like at the end of the week (fingers crossed !!)
cost wise
AP is about £200
Sachs is about £400...(good for 400 hp + !)

 

[arawson]

I've seen your clutch. John showed it to me last Friday and very nice it was too.

 

[mpen]

I had terrible clutch slip in my stage 3 aero and that was on a new saab clutch of about 5k,

 

[mark e]

I suspect the problem with clutch slippage is down to weak springs on the pressure plate rather than the limit of the friction material. Normally when a clutch is replaced, it is just the friction plate and not the springs as well, which can get tired. Obviously this won't show up on a standard car, but give it a bit more torque and it can be an issue.

Also, it could be that the friction surface has got glazed through repeated slippage. Try not to be so heavy with the right foot and only let it "slip" on 1st gear take up- time to practice matching engine revs to road speed for a while and you might find that you get some grip back. This worked on my C900.

 

[arawson]

mpen

Is your clutch still slipping or did you cure it. If so, how?

 

[SteveN]

Originally posted by Mark E
I suspect the problem with clutch slippage is down to weak springs on the pressure plate rather than the limit of the friction material. Normally when a clutch is replaced, it is just the friction plate and not the springs as well, which can get tired. Obviously this won't show up on a standard car, but give it a bit more torque and it can be an issue.[/b]

Just had the 2.3 9000's clutch done. Mine is stage 1 & has 401Nm of torque. IIRC the 9000LPT clutch was originally rated for 408Nm so stg1 put me pretty close to the limit. Carlssons, who did the work, told me SAAB have recently beefed up their 9000 clutchs.

 

[zeke]

mark e, I think you're right about the pressure plate. I replaced my stock pp with Sachs Race Engineering. I should have bought it sooner than I did - it jumped 100% in price, in little over 6 mos! I could have bought it for $200 in the fall, and ended up paying over $400 in the spring And, it's increased since. But seriously, ylee, although I have no issues with slipping, others who have had their flywheel resurfaced, have had problems with disengagement. It seems that the clutch pedal disengages at a lower position - this would make sense if the springs/fingers, that mark e speaks of, are stiffer. But if the flywheel is resurfaced, it also lengthens the distance that the t.o. bearing has to travel, in order to release the clutch. I don't think the actual travel involved by the t.o. bearing is all that much. Anyway, the higher rating on those springs and the resurfacing of a flywheel could lead to a clutch pedal that's not low enough, literally, to get the vehicle into any gear. I know of one person who did this. He ended up removing the transaxle twice - the last time with a new stock clutch/pp. In fact, Quasi was there lending a hand. I wonder if there's another t.o. bearing, one that's a few thousandth wider in the axial direction, that could replace the stock one?
I haven't had this problem with mine. My clutch pedal disengages at a lower point, than it did, and some find the pedal a bit 'heavier', but I don't find it uncomfortable. I have the stock clutch plate. I'm also running much higher boost pressures than the previous software, yet the pp does it's job. I haven't noticed any slipping since I changed - 30k miles ago. Mark's right about the glazing - my clutch had plenty of friction material left when I changed it. However, once one starts raising the boost level, it's only a matter of time. I never go thru the gears that fast. But my previous software gave 290 ftlbs at the wheels, and after 20k miles I started noticing slippage, in 5th on the highway

 

[Friberg]

The Sachs Race Engineering pp actually needs a special friction plate that is thinner than the stock one. Unfortunately Sachs stopped making this friction plate for a while, but hopefully they will start again soon.

A cure for this (that I haven't tried yet) is to get 0,5 mm schims to place between pressure plate and the flywheel. Don't take your average washers since the schims have to be very similar in thickness.

 

[sgould]

Robert,

I've not had a Saab clutch refaced, but I have had three "other makes" done by the local engineering company. I each case they have machined the clutch mating face and then machined a similar amount from the fixing face of the pressure plate etc. so that the distances stay the same.

What have I missed that prevents you doing the same on a Saab?