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Old 11-08-2006, 08:49 PM   #16
Patrick Olsen
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Member#: 120
Join Date: Jul 1999
Chapter/Region: AKIC
Location: Where the Navy sends me...
1997 Legacy 2.5GT
1996 Impreza coupe


Originally Posted by jtmcinder View Post
Nope. Those are viscous limited-slip devices, not viscous power couplers (which are more like differentials). Viscous power couplers are used in cars like VWs (4-motion) and Merecedes (4-matic), but not the WRX or RS. If you can't keep straight which component is splitting and transferring torque and which is limiting slip, you are in serious trouble.
In the interest of providing useful information to this thread (rather than just derisively pointing out how stupid and wrong Unabomber is), could you explain what the difference is between a viscous limited slip device and a viscous power coupler? Or at least provide a link to something that explains what they are? Subaru (and other auto manufacturers) seems to think those viscous things are differentials, I'm curious what the difference is.

Originally Posted by jtmcinder
One of the most common misconceptions is that the DCCD controls torque split. It does not. It controls the locking of the differential.
Does the amount of differential locking directly affect the torque split, or how are they related?

Originally Posted by jtmcinder
Torsens respond to differences in transmitted torque. They react. They don't lock until they need to.

Clutch-packs lock as a function of input torque. They don't wait for a loss of grip; they lock in advance.
This is the opposite of what I've always understood. I thought that a clutch type differential, or a viscous diff, required some slippage to occur in order for it to start to work. Hence the term "limited slip" - it's not a "prevent slip" differential, because there has to be some slip in order for it to begin to work.

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