The stock rear differential in both the 135i and 335i is an open differential from the factory. This means you can only put power to the ground on 1 wheel. With an aftermarket rear differential like the Wavetrac, you can now put power down to both wheels!
During a turn, the weight of the car is transfered to the wheels on the outside of the turn. With the weight transfered to the outside, the inside wheel will now have less traction. In an open differential, power is sent to the wheel that has the least amount of traction. This means that if you applied power in mid turn, power would be sent to the inside wheel and thus making it spin and lose traction. With the Wavetrac Limiited Slip Differential (LSD), power is sent equally to both drive wheels giving you the ability to apply power in mid turn. This equates to better traction and thus faster exit speeds out of the corner. As any racer will tell you, exit speed will make a big difference in your lap times.
Whether you track your car or not, upgrading to the Wavetrac LSD will completely change the dynamic of the car under power. You'll be suprised how much more traction you have, even driving on the street!
335i with manual transmission (up to 2/2007) [BOLTED]
335i with manual transmission (3/2007 to present) [WELDED]
335i with automatic transmission (up to 2/2007) [BOLTED]
335i with automatic transmission (3/2007 to 9/2007) ]WELDED]
335i with automatic transmission (10/2007 to present [BOLTED]
135i with manual tranmission (all) [WELDED]
135i with automatic transmission (all) [BOLTED]
Early 335i (up to 3/2007) all came with a bolted rear differential. This made it possible to just swap the rear differential to an aftermarket LSD. However, starting 3/2007, BMW started welding the ring gears in the factory rear differential to the differential carrier on both the automatics and manual transmissions. This made it very difficult and expensive to change differentials as you would need to buy a brand new final drive from BMW. Not anymore. Wavetrac is now offering a service to modify your welded factory differential to work with their LSDs. The welded ring gear in welded factory differential is CNC machined and seperated. Once seperated, the ring gear is CNC machined and modified to accept the Wavetrac LSD. Check the chart below to see if you need the installation kit.
Automatics built from 9/2007 changed to a slightly different differential. However, all automatics after 9/2007 are all bolted and thus do not require a installation kit.
All 135i manual transmissions are welded.
All 135i automatic transmission are bolted
Core exchange program!
Installation of any LSD into the rear differential assembly requires a transmission specialist. However, the Wavetrac LSD is now available preinstalled into the rear differential housing. We offer a core exchange program whereas we send you the entire rear differential assembly with the Wavetrac LSD preinstalled into the rear differential housing. It is then ready to be install in your car. You remove your old rear differential assembly and install the new one. This saves you the downtime of shipping your rear differential assembly to us and then waiting for us to send you your rear differential assembly with the Wavetrac LSD installed into the rear differential housing back to you. The $800 core charge is a deposit. Once we receive your rear differential assembly, the core charge is returned back to you.