As your E36 or any BMW climbs in mileage bushings are one the most regular things to deteriorate. Just like suspension bushings and mounts the rubber starts to dry out and crack allowing for more play in the bushing which is NOT good for performance or general drivability. From the factory the E36 comes with rubber drive train mounts and bushings. The engine mounts are rubber, transmission mounts rubber, and you guessed it, the differential mounts are rubber. These rubber mounts are great for the road because of their longevity and there resistance to transfer drive train noise and vibrations into the chassis and cabin of the car.They may not be the best option if tracking or racing your E36 or other BMW.
That is why most of us want something better when we decide to replace or upgrade these mounts. That is why Turner makes solid mounts that improve your cars performance and feel. While these bushings may improve the performance and feel of your car on the track they may not be ideal for everyday street driving.
TMS E36 solid differential bushings are designed around SCCA SPEED World Challenge regulations and have years of street and track testing to prove their performance. Replacing your diff's rubber mounts with this kit will result in a snappier feel when cornering and better suspension performance. This kit will also prevent the front differential mount from loosening up or shearing -- a very common problem with the E36. This is also known as the "diff bolt". The rear two differential cover bushings are slotted to allow for compliance between manufacturing standards as BMW specifies. These bushings are CNC machined from high-grade billet aluminum and Delrin. The kit includes 3 pieces: a Delrin front mount and 2 aluminum rear mounts.
Making sure your rear differential bushings are in good shape is critical when tracking your car. Your rear differential bushings can become elongated which creates unwanted plan allowing your differential to move when under load. This shifting between on and off load can snap or shear off the front differential bolt. Since this bolt is threaded into the differential casing its self shearing it off can leave the threaded end inside the diff casing. In this case you must remove the entire diff from the car, drill out the sheared part of the bolt and re tap the hole for the new bolt**. Installing solid differential mounts can eliminate that play and prevent this from happening. There are also some differential braces that can prevent this as well.
**Many people drill out the threads in the diff casing and use a longer bolt with a nut on the end of it so in the event that the bolt shears they can remove the bolt easily and replace it without removing the differential.
Turner Solid Motor and Transmission Mounts for E36
TMS solid mount kits will hold up to the abuse that a powerful, high revving race motor will induce. The main benefit is that they reduce the torque and power lost from rubber mounting movement. Rubber mounts absorb the energy and vibrations produced from the torque of the motor. By not allowing that motion and energy to be absorbed, more power is transmitted faster. The solid engine mounts locate the engine in the original orientation, but 5mm lower, and the transmission mounts are 1mm lower than the original mounts and are also located in the original orientation. This lowers the car’s center of gravity and improves the overall handling of the car. These are the exact mounts used on the Turner SPEED World Challenge race cars. To get the best results it is recommended that you use the solid mounts all the way down your drivetrain. Mixing rubber and solid mounts can ad stress to some parts of your vehicle. View solid motor and transmission mounts for E36 here.
Some race sanctioning bodies and classes do not allow solid motor mounts such as SCCA ITR and other restricted or stock classes. If you are planning on running your car in one of these classes please refer to the rule book before installation.
So there you have it, changing your drivetrain mounts can improve power transfer, suspension performance, lower the center of gravity and give your BMW a snappier feel when accelerating. These mounts are a relatively inexpensive way to improve your track or race car's performance and durability under the stresses of high performance driving.
Other things to think about:
When replacing these mounts and bushings on your driveline you may also want to replace your guibo (flex disc) which is a vibration dampener mounted on the back of the transmission. The flex disc acts as a buffer between the transmission's output shaft and the driveshaft leading back to the car's differential. The only way to tell if the guibo is beginning to wear is getting under the car and visually inspecting it for small cracks and other signs of wear. If the guibo is severly worn you will notice a harsh vibration when starting from a stop. In addition to replacing your guibo a center support bearing may also be a good thing to replace while working on the driveline.A full selection of E36 guibos can be found here.
A worn-out center support bearing can lead to some annoying side-effects. The driveshaft on BMWs is broken up into 2 sections. The center support bearing is where the 2 sections meet. It consists of a metal bearing in the middle that is surrounded by vibration-absorbing rubber. As the vehicle ages the rubber becomes weak and rips away from the bearing. The result is a vibration and a bad thumping or knocking sound. Replacing both the center support bearing and the guibo at the same time as the driveline mounts can really imporve the feel of your BMW while under acceleration, especially at high speeds on the track. Center support bearings for your E36 here.
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