MRF solid aluminum subframe bushings

[Rassilon]

Has anybody tried solid subframe mount paired with stock diff mount?

[Hujan]

Originally Posted by edwardgtxy

Has anybody tried solid subframe mount paired with stock diff mount?

I know MRF has done at least one car like this and someone on this board (in another thread) recently swapped back to the OEM rubber diff bushings while keeping the solid aluminum subframe bushings. They reported that it sounds stock (i.e., that there is no differential whine).

[aus]

Originally Posted by pbonsalb

I will be running poly subframe and diff bushings. If you hard mount both, you should expect some NVH because you just eliminated any isolation. I agree both do not need to be isolated as they are with stock rubber. You could hard mount one and isolate the other. I am going to split the difference and simply firm up both with a fairly hard poly from AKG, but softer than delrin or aluminum. I have done this on other cars and the result has been good. My car is a street car and I do not want to take away from its daily drive ability. It has to be OK not just to me the enthusiast who can tolerate some added NVH but also to my wife. Otherwise, I will be driving with her in her station wagon. The wagon is decent -- an 08 535xit but I would rather be driving with her in my 08M3. Have to make some compromises in life.

Just wondering if you had the poly bushings installed. If you had them installed, hows the NVH?
.

[pbonsalb]

Still have not gotten to that project unfortunately but it is on the list for this fall. Currently leaning towards AKG red for subframe and AKG black for diff, but would consider harder on the subframe like delrin or even solid. But my E90M3 is a street car, not a racecar. I have a turbo E36M3 that I have compromised as much as I can bear in terms of daily driving ride/noise quality.

[Rassilon]

Originally Posted by Hujan

I know MRF has done at least one car like this and someone on this board (in another thread) recently swapped back to the OEM rubber diff bushings while keeping the solid aluminum subframe bushings. They reported that it sounds stock (i.e., that there is no differential whine).

Nice, thanks for the info. I can actually hear some faint diff whine in stock so I definitely don't want any additional increase in sound.

[Richbot]

Originally Posted by Hujan

I should have grabbed a ride from you when you were here. I am definitely going with the solid subframe mounts but still a bit gun-shy about the diff situation, especially reading Longbow's saga.

One question I have is how much of a PITA it is to swap the diff bushings. I know that swapping the subframe bushings is a very involved process, but the diff is much more accessible, no?

I know this is an old post, but the diff is more accessible in the same way that the top of Denali is more accessible than the top of Everest. Still a PITA, just less of one.