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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
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There is a specification for that and it can be measured with an inch pound torque wrench turning one wheel hub to measure the resistance while the other is not allowed to turn.
The clutch pack can be shimmed up or 4 new clutch discs installed to raise the limited slip percentage or bring it back to origonal spec if worn. You can also remachine some parts to fit 6 clutch discs and plates - 3 on each side in there if wanted.

I don't know the turning resistance spec but you could find it somewhere or from someone that rebuilds 930 LSD's.

The way the LSD is designed the pressure applied squeezing the 4 LSD clutch discs and plates increases with engine torque.
The spider gearsets teeth are cut at an angle in a way to push away from each other under load while the LSD carrier surrounding them and the clutch discs limits how far thay can push away from each other and thats how the pressure on the clutch discs is increased under load.

It's hard to describe how the ZF LSD used in Porches and BMW's works without referencing to an exploded diagram or having one apart on a bench in front of you.
Old 12-30-2009, 09:34 AM
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