It's funny you sent me that e-mail about the torsen creator. I just found
some evidence that torsen was never used in Audi racing. The 90, V8 ETC, and
even the A4 never used it. In fact, drivers flat out refused to drive it,
even Stuck and Rohrl. I have no idea what they used, but it wasn't torsen.
Torsen sucks as a performance feature. It is an impossible system, with the
ever present danger of incorrect torque split. How Audi can use it is beyond
me. It's great for consumer cars, ONLY.
And the only other system Audi used was open diff, which only works when the
center is locked, and thus it is 4wd, not AWD.
In light of what you and I have found, maybe it's time to realize that Audi
hasn't done great things with AWD at all. Maybe they offered an affordable
system for a family sedan type deal, but it is not high performance.
Good family sedans, nothing else. VW.