MIP Super Diff Bi-metal kit review (B6)

I needed to rebuild the diff in my B6 (it was the one I ran in my B5M), so I decided to upgrade to the MIP super-diff with bi-metal outdrives.  Cost was $41, or about $20 more than a diff rebuild kit, so it makes it a pretty good deal.

The bi-metal outdrives consist of aluminum diff ring holders that mate into steel outdrives.  This gives you the combination of a lightened diff with the durability of steel outdrives.  I considered getting the full pucks system with aluminum outdrives, but the increased maintenance made it unappealing.

The bi-metal outdrives alone drop the weight by about 0.3 oz. (8.5 grams).

It’s a nice little upgrade.  The weight is also reduced where it affects the most, which is furthest away from the centerline.  A nice bonus is that when you need to replace the outdrives, you can replace just the steel part.  You don’t even have to remove your diff to do this, you can leave it in the transmission on the car!

Testing it on the track, it felt like my B6 had much more acceleration.  Jumps that I could barely clear before, I could mess up the approach and still clear.  I’d say the acceleration/power difference was about 10%, or about the difference of the slipper eliminator.

Pretty slick and a nice upgrade.  If you reuse your existing diff rings/balls/thrust, you don’t have to get the whole super-diff bi-metal kit, you could just buy the aluminum diff hubs and steel outdrives and save a few dollars.