Limited Slip Differential
05-21-2006, 09:18 AM
#1
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Limited Slip Differential
According to the Porsche 911 Red Book, all 993tt's came with the G64/51 transmission with a limited slip differential.
On two wheel drive 993's, the LSD can be tested by jacking up the rear end, rotating one tire, and seeing the direction of movement of the other tire. If the other moves in the same direction as the first, the LSD works. If it moves in the opposite direction, the LSD clutch packs are shot.
In the experiences of those around me, a tracked 993 NA will get one or two years out of the LSD clutch packs. I'm curious what others on this board are finding with their cars, especially those doing DE events.
Can anyone confirm that all 993tt's came with the LSD? Does anyone know the LSD ratio on the 993tt (80/20, 60/40...), and whether the same test applies to the 993tt all wheel drive?
Jim
On two wheel drive 993's, the LSD can be tested by jacking up the rear end, rotating one tire, and seeing the direction of movement of the other tire. If the other moves in the same direction as the first, the LSD works. If it moves in the opposite direction, the LSD clutch packs are shot.
In the experiences of those around me, a tracked 993 NA will get one or two years out of the LSD clutch packs. I'm curious what others on this board are finding with their cars, especially those doing DE events.
Can anyone confirm that all 993tt's came with the LSD? Does anyone know the LSD ratio on the 993tt (80/20, 60/40...), and whether the same test applies to the 993tt all wheel drive?
Jim
Last edited by jdlesliemn; 05-21-2006 at 10:32 AM.
05-21-2006, 09:45 AM
#2
I have just this week gone through the testing procedure so may be able to offer some advice.
With the car in neutral and one rear wheel off the ground their should be resistance to rotating. To go further, disconnect a drive shaft and try to turn it with one hand. It should take around 10lbft to turn it.
I did these tests, then removed the diff while the engine and box were out and sent it to Parr for a rebuild.
With the car in neutral and one rear wheel off the ground their should be resistance to rotating. To go further, disconnect a drive shaft and try to turn it with one hand. It should take around 10lbft to turn it.
I did these tests, then removed the diff while the engine and box were out and sent it to Parr for a rebuild.
05-21-2006, 10:10 AM
#3
Nordschleife Master
The stock 993tt comes with a relatively low locking pressure ring, I believe it is a 25/40. The factory street uses 2 friction plates rather than 4 like the Motorsport and the plates aren't nearly as strong. They do wear out, especially if used on the track. The motorsports ratio is 40/65 and Paul Gaurd offers 50/80 and 80/80. If it were me, and I needed a new differential due to worn out parts, I would use the stock TT housing and install the 4 plate motorsport insides with the 40/65 pressure rings.
