STaSIS 4:1 Center Differential on a B6 S4

17 11 2008

After a few weeks in the shop, we installed the STaSIS 4:1 center differential on my B6 S4. The stock differential provides 2:1 torque distribution, with the modified STaSIS unit we’re able to provide 4:1 just like the B7 RS4.

I have not had a chance to take the car to an HPDE yet, but I have noticed an immediate difference coming out of the apex of a corner. Typically when you’re exiting, the car begins to under-steer; with the diff the moment you begin to under-steer the power is transferred from the front to the rear and we can neutralize some of this under-steer.

There has been no odd behavior from ESP or ABS. The only thing I’ve noticed post-diff has been some Quattro binding at low speed turning, such as in parking lots.

This modification is available for 5 and 6 speeds, manual A4/S4s.

The install was simple, expect approximately one hour for the install and reinstall. Start by disconnecting the center drive-shaft. The drive-shaft is held in by six allen key head bolts, be careful not to strip these. We heated the bolts with MAAP gas to loosen and burn off any Loctite.

Once the bolts are out, the Torsen housing can be removed, and the differential can be removed. Slide in your new unit, refill the transmission fluid (it’s shared with center diff) and you should be good to go!