Performance Gearing: from 0 to amazing, custom-built for performance and power
How it works
Anticipatory vs. Reactive Response: or, Why All Limited Slip Units Are NOT Created Equal.

A limited slip differential that is anticipatory is preferable to one that is
reactive. This is because reactive units must have relative wheel slippage
occur to generate any dynamic lock – otherwise, no lock is present and
traction is no better than that which would come from an open differential.
There is always a reaction-time delay before these units generate enough dynamic
lock to regain traction. Because these reactive units are based on hydraulics, the
TOTAL amount of dynamic lock is limited to about 60%. The two examples of
this type of limited slip are the M-variable, used in all M models since the
introduction of the E46M3, and the E30 Viscous units found in "ix" models.
Since '95 , limited slip was discontinued as an option for all but a select few BMW models. Only those with "M" engines have limited slip differentials...in fact, they're standard equipment. Now, all BMW models have a Traction Control system. It's a terrific safety feature, and it's been used since the early 90s -- even on "M" models. But let's be perfectly clear...Traction Control is a safety feature, and NOT a performance enhancement. The driver in a vehicle equipped with Traction Control never experiences the feeling that comes with an "open" differential -- which is to say, the spinning of one rear wheel out of all proportion to the spinning of the other rear wheel. When this occurs, the Traction Control system applies brake pressure to the spinning tire, and actually retards the car's timing to "throttle down" the automobile in an effort to regain control.
See? Very safe. And safety is a good thing. But let's be clear. Traction Control is not the kind of thing that enhances your performance. It's specifically designed to impede your performance (in a very helpful way). But this is such an important distinction for drivers who value complete control and performance that we're going to say it again. TRACTION CONTROL IS A SAFETY FEATURE, NOT A PERFORMANCE ENHANCEMENT.
- Fits all '95 and later models
- Salisbury style, friction discs/mechanical ramping configuration
- All units contain 5 friction discs for type 188K/L and 4 friction discs for type 210/220/230
- Static lock range of 25% to 55%, with on-demand dynamic lock augmentation
- Customized building - street only, street/track, and dedicated race applications
- 3 year warranty, unlimited mileage
Limited slip transfers the torque being lost in a spinning wheel (that is, one with with little or no traction) to the opposite rear wheel which has more traction, without braking or losing power. Even if one tire leaves the ground, limited slip static lock will transfer power to the wheel that still has traction.
