Cusco RS Type Rear LSD STI R180

SLIP LIMITED, TRACTION ENHANCED

Cusco strives for total balance with their products. The RS Type limited slip differential offers a finely tunable solution for improving distribution of power to the wheels.  It is a plate (clutch) type with centrally located coil springs providing initial torque (preload).  This arrangement improves the progressive nature of the diff locking while reducing the rate of disc wear.  Most limited slips incorporate two sets of ramps for tuning purposes.

These limited slips can be tuned for the type of use, driving style, road surface, etc. through multiple avenues.  Changing ramp angles will change the lock rate as torque is applied and can change the on-throttle and off-throttle settings depending on the angles on each side of the cross shaft (1-, 1.5-, and 2-way).  Changing the plate order can alter the number of active friction surfaces to reduce or increase the locking percentage.  Changing the thicknesses of the plates and the number of coil springs fitted alters the initial torque value.

The purpose of a differential is to allow independent rotation of wheels across the axle (front, rear, or center in an AWD application).  This is necessary due to the variation in rotational speed while cornering due to the different arc radii that each wheel travels.  An open differential allows free independent rotation of the two axles but will direct torque to the wheel with the least traction allowing for that wheel to lose traction early preventing early application of power at corner exit.  A gear type (Torsen or Helical) LSD uses a gear mesh arrangement to bias a percentage of torque from the low traction side to the high traction one.  However, when traction is very low or one wheel is off the ground little, or no torque can be transferred, and the unit works like an open diff.  A plate type LSD has a set of friction plates that are preloaded to some initial torque allowing at least some torque transfer even with zero traction or a wheel off the ground.  It also is capable of transferring high torque evenly and at an increasing rate according to the input torque from the engine This makes it by far the most effective limited slip option for motorsport especially with high power levels.  The downsides of a plate type LSD is greater influence on the handling balance of the car (usually negatively at corner entry and positively at corner exit) and noticeable noise and binding during tight cornering.  Additionally, this type of LSD requires frequent oil changes and eventual rebuilding to restore performance when clutch plate wear reaches an undesirable level.

This LSD is convertible by moving the cross shaft to a different set of ramps (requires LSD disassembly).  It converts between 1.5way (off-throttle LSD action is 50% of on-throttle) and 2way (on and off throttle LSD action at same rate).  Please select the way you would like the LSD ramps to be provided.  If you need additional modification such as lowered locking percentage, please contact us about your order.

Manufacturer Part Nos: LSD 182 L2, LSD 182 L15

What it fits:

• STI MY01-21 (TY856 MT)
• WRX/STI Type RA MY96-00
• Legacy Spec B (TY856 MT)
• Forester STI (TY856 MT)