In my LSD, I had four plates on each side as original. There were two of each type,arranged so only one pair of faces were driven separately: AA-BB, only the one A-B interface slipped. I just re-stacked them like shuffling cards to ABAB so there were three slip interfaces : A-B, B-A, A-B.
You can also arrange them for two slip faces: ABBA, so the A-B and the B-A faces slip. You get a 40-45% ratio. Or for cheaper parts, AABA, which slips on both sides of the one moly plate (but it wears faster). This gives you a bit less ratio than ABBA.
The critical thing in making the LSD work as you want is how closely they fit. The outer cover on one side sets the total spacing for all the plates and the central spur gears. Imagine if you put an entire extra plate in there so that the stack was so high that that bolt-on cover didn't fit - as you tighten the bolts, the stack of slip plates gets compressed really tightly. Tight enough and the diff is essentially locked in place and both axles turn as one.
A little less tightness and the plates slip. So you can adjust the real lock ratio by adding a shim of some thickness under the cover or around one of the plates. And the tighter you make it, the more wear you will get. BTW - the LSD actually is meant to works with a bit of looseness in the plate spacing. Gear lube gets in there and affects the stiction because of its shear viscosity.
Of course, the gear lube is important too. The rough looking plates are nodular moly steel just like the syncro rings in the TX. The right gear lube is very important in getting good function in both. Fortunately, the same lube works well in the LSD diff as in the moly syncro TX. I use a single wt 90 EP (the Ep is for moly syncros). Some racers use Synthetics like Mobile 1 or Red-Line products. Ask your fellow racers.
In a race car, the diff is fairly easy to take apart; experiment with one, two and three sliding surfaces on each side, and with various shims . The only real measure is how your lap times are.
Last edited by 60sRacer; 11-18-2007 at 03:17 PM.