Unless you tackle your commute as aggressively as Allan McNish rounds Road Atlanta, you’ll likely not truly appreciate Audi’s new Sport Differential until you hit some substantially slippery roads or attend a local track day. This new piece of kit is an algorithm controlled rear hydraulic differential that distributes power between the rear wheels. By sending torque to the outer rear tire in a turn, this added push helps bring the tail around and minimizes understeer.
The new physics of the Sport Differential are both a safety feature and a performance gain. From a safety standpoint the setup operates much like ESP, only using the throttle rather than the brakes. Further acceleration at that outer rear wheel can not only minimize understeer but it’s also good for tail-out fun should that be what you’re looking for.
While we just driven our US-spec 2010 Audi S5 on the streets of Audi’s home town in Ingolstadt, Germany, we’ve tested the new Audi S4 with the Sport Differential on wet and dry tracks and find the effect of the new Sport Differential to be confidence-inspiring when used for stability and transformative when intentionally used for oversteer. So-equipped, an Audi with Sport Differential is second only to the Audi R8 in its willingness to hang its tail out and largely in a very controllable manner.