Awd LSDs are difficult to understand due to the interactions between the front, center and read diffs. I comprehend the reasons behind the RWD and FWD but AWD remains elusive. Many RS4s have installed a rear LSD and have been very happy. To me that’s odd because I would think that a front LSD would be more beneficial since it always seems that in my driving the fronts slip first. Then there is the 60:40 split on the center diff further complicating things. I found this link that explains the issue based on DSMs http://farnorthracing.com/autocross/diffs.html so it should be applicable. JHM makes a rear LSD and most people have installed the rear one. This link on Audizine http://www.audizine.com/forum/showthread.php/535684-My-(also)-Ibis-RS4-Build-Thread talks about road racing a clutch based rear LSD. Maybe you guys can shed some light on the mythical LSD for the RS4 AWD car?
From that article I think that 1.5 way http://www.osgiken.net/products.php?product=lsd is the one that you want but what makes the most difference front, rear or all? I’m assuming that the front would help with the understeer. Thoughts?