Project BMW 335i Sleeper - WaveTrac Limited-Slip Differential Install - Super Street Network (blog)
But BMW never offered a factory limited-slip differential (LSD) option for the 335i and 135i, and the cars come with an awful open differential. Our 2007 BMW 335i, with its six-speed manual transmission and 75,000 peachy miles, was in dire need of a traction overhaul. We got in touch with Wavetrac, Autotech Driveline's differential company, and got ourselves a bookshelf-worthy piece of equipment, the Wavetrac Torque Biasing Limited Slip Differential. Essentially, the differential is a set of gears powered by the engine and transmission (and in RWD and AWD vehicles, a driveshaft) that work together to turn the axles going out to the drive wheels of a vehicle. It allows the wheels to spin at different rates of speed, which is necessary if you want your car to turn without tire slip. For example, if you were to drive in a circle, the inside wheel needs to travel slower than the outside wheel to allow smooth movement. There are three basic types of differentials: Open, Locked, and Limited Slip. Open differentials always supply the wheels with the same amount of torque. The maximum amount of torque supplied is limited to the greatest amount that will not make the wheels slip. Source: www.superstreetonline.com
