Modification notes 2: Differential lock down kit

[Twinz]

Been running the DEFIV kit for a few months. Here are my impressions.

The intention of the kit is to eliminate wheel-hop and to improve shift-feel, load characteristics and off-the-line racing.

* 100% Bolt in
* 100% CNC cut lightweight aluminum
* Replaces 3 weak rubber OEM Bushings
* Adds a 4th arm and link to the differential

Red arrows indicate the install of the arm and bushings:

Impressions:

The kit was easy to install and fitted perfectly with no modifications required to the subframe.
Off the line acceleration was absolutely amazing...the rear felt solid and connected to the road. Cornering was just as pleasing. But all this amazing grip could not overcome the huge increase in NVH and harshness. It was really loud and bad between 1500 - 2500 rpms.

So I removed the aluminium bushings and replaced them with e92 M3 v8 subframe bushings which is stiffer than the stock 335. This resolved and reduced the NVH dramatically. The car is not as tight in the back as with the aluminium bushings but feels a lot more compliant and still gives the solid feeling that I was hoping to get.

For track use I recommend the alluminium bushings without question.

Here is an alternative and cheaper brace option:

The differential brace for the M3 e90/92:

DIY HERE

:ty:

 

[moranor@axis]

nice writup im sure these will work well for a full track car

Powerflex do offer polly diff mounts for this car as another alternative for tightening up the diff with low NVH