Quote:
Originally Posted by group911@aol.co
Interesting. I've never seen one before. It seem kind of pointless.
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They are great on a street car, and do have their place in racing. They are the basis of Audi’s Quattro systems from the early days. For a center differential on an awd system they are awesome.
So let’s say you’re in a corner, and your inside wheel hits some kitty litter and spins up a bit. For our simple example, let’s say it still has 20% of drive power going through it. The outside wheel will in turn get 80%. They are very smooth in operation, adjusting drive side to side pretty seamlessly. Wavetrac and Quaife are TBDs.
A Salisbury lsd, on the other hand suffers some drive loss, based on its nominal limit. If we take a 40/60 LSD as an example I think it will become more clear. First off, those numbers do NOT need to equal 100. That’s a very common misunderstanding. The first number is locking percentage on throttle and the second number is lock on overrun. That’s Porsche’s way (there’s a formula in the factory manuals to calculate drive forces). If you talk to a BMW or muscle car guy, they talk in ramp angles, not percentage of anti slip effectiveness like Porsche does.
So let’s go through that same corner. Inner wheel slips and the pins move up the ramps of the pressure rings, causing the clutches to lock. Because of the angle of the ramp combined with stack height (and number of clutches) there is a limit to how much power goes to that outside wheels. It’s 40% in this instance. That’s the limit of the lsd. And it will get that much of the power no matter how little traction is available on the other side.
I suspect Bill Verburg will come along at some point here and provide all the fantastic pictures and additional detail that he has in these discussions in the past.