Turbo and Downpipe

[matt]

you rebuilt the slave and rebled the system I assume.

[Jordan]

Unless I'm mistaken, the slave cylinder only releases the spring pressure from the clutch disc, when the clutch is out pressure is applied through the clutch fingers so the slave really has nothing to do with the clamping power. Unless it is somehow physically interfering with full release. The mushiness he could be feeling is the weaker fingers.

Luke , what brand is the clutch disc? Sachs? Is the thickness of the pressure plate any different than a stock?

[Crazyswede]

Correct, if the slave fails then your clutch will work...its just that much harder to change gears. The slave should not have any effect on whether the clutch slips or not.....unless possibly if the slave were the wrong length and at rest was putting pressure on the fingers.

[Luke]

Its an "AP" pressure plate. Like you said the slave could have an effect if it is not releasing properly but I just rebuild it and watch it stroke as someone else pushed the clutch and it moves in and out fine. I have also had the rubber in the clutch hose go bad and cause similar symptoms because the as the clutch releases the hose constrictes reverse movement of the fluid and hold the clutch depressed, but the hose is only a few months old and its nice telfon steel braided.

[matt]

At this point I would like to defer further discussion to one of my favorite tools, the hammer. I say you just bash the fucking thing until it gets into line and stops messing about.

[allessence]

Not that you guys need this info. I had posted it to SAABcentral. I like the hammer thing. I extruded and oring on the slave before and had to take the muffler gun to it.

The 9000 pressure plate is simply a larger sized earlier designed 900 pressure plate. In other words they used the same thickness diaphram spring but increased the outside diameter.

When they went to the larger diameter they actually decreased the LBs sq/in as the larger diameter has more suface area.

This translates into larger rotating mass which slows down the rev's and has less pressure per sq/in on the larger clutch disk.

The smaller 215MM has less mass/less Sq/in in surface area and is supposed to have greater clamping force. And it does. The later 9000 switched back to the 900 earlier style. From what I have been told the Sachs 215mm pressure plate is the best for hold.

My car is upgraded and the stock 91-94 900-9000 model wouldn't hold even with brand new everything with only injector upgrades.

I put in a brand new Sachs smaller 215mm and everything worked up until I modifed more stuff. Back to slipping.

I called SD and told them I am sick of the clutch problems and to send me a 6 puck. They said are you sure. I said yup. A 4 puck (any material) is way to harsh on the street. It is for the most part in or out. Even with a very light feathering of the clutch pedal there is very little room for slipping. Again (in or out not much in between) way to aggressive for the street/everyday driving.

The 4 puck raises the pressure on the puck surface as well as the pressure on the surface of the flywheel and pressure plate. Picture sitting on a regular chair and then flip the chair over and sit on the end of the legs. Not very comfortable since now all the pressure is going onto 4 points.

The 6 puck offers a dramatic increase in lock up but with less agressive in and out. So it can be feathered and controlled much better.

So, I ended up with a carbon/kevlar/ceramic/copper 6 puck. The flywheel is getting gouged (alum with replaceable steel face no biggy) and the clutch pressure plate will be no good when it comes time for replacement. I never reuse old pressure plates anyhow.

I believe the setup I have now will allow for me to hit 300hp with no slipping.

[allessence]

Luke where did you order the STsteel from? Which grade 304, 316, 321?

I am guessing you have not CAT. Are you using custom made exhaust behind the CAT or MSS or = ?

J

[Luke]

Its 304. I ordered it from summit because I needed it fast to get the turbo installed and they ship ground to me in 2 days. Its probably available a little cheaper somewhere else. This ebay store seems to have good selection. http://stores.ebay.com/Mandrel-Bending- ... esstQQtZkm

[Luke]

Ok I cut off work early today and went over to Johns shop where we did a blanchard grind on the flywheel. The thing looked like a washboard as we started to remove metal to make it flat. I was surprised how wavy it was. Anyway we put a nice surface on it. I reinstalled it tonight and when the roads clear up enough to put any power down i'll see if I still have the slipping issue. Hopefully not.

[matt]

i hope that does the trick, a shitty grind on the flywheel could explain every damn thing.