KMP Differential Bushing & Bracket Set - F8X M2/M3/M4
KMP Drivetrain Differential Bushing & Bracket Set (diff lift kit)
Take advantage of a second rear diff mounting point plus raise the diff for better axle/driveshaft alignment, especially on lowered vehicles.
The solid bushings will have near-zero flex, meaning more power transferred to the wheels and more direct, positive feedback and road feel. Also eliminate the potential failure of stock rubber bushings.
This kit includes the front bushings, rear bushings in subframe, and a new rear bracket with two upper mounts instead of the single-mount design used on the original.
All mounts are either solid aluminum or a hybrid Delrin/aluminum that provides a more direct response and near-zero deflection compared to the factory rubber or urethane mounts. On race cars we prefer aluminum or Delrin to minimize deflection as much as possible. While urethane might be fine for street use they pale in comparison to solid when used on the track. Solid materials have almost zero wear and tear, eliminating another maintenance item from your list.
The front mounts in this kit are offset 10mm higher than standard mounts. This raises the diff to better align the rear axle shafts with a lowered suspension. As you lower the ride height the angle of the rear axles becomes more extreme, which could cause premature failure in the CV joints. Raising the diff also helps with clearance between the ground and the diff cooling fins. Because of the solid nature of these bushings we only recommend them for track use. We do offer factory urethane and Powerflex urethane if you want a more street-friendly bushing option (but without the height correction). The new rear bracket includes a 2nd mount for the passenger side bushing. There is a place for the mount in the rear subframe but BMW chose not to utilize it. The KMP bushings do away with the factory vibration absorber on the upper bolt. New upper hex bolts are included.
Note: front bushing bracket not included. The supplied bushings will need to be pressed into your existing bracket. A small amount of the casting must be ground off for clearance.