[Potty Mouth]

F22 M235i owner here- I recently upgraded both subframe and diff bushings to Delrin and although it rides on rails now, the whining noise from the diff is too much. Wondering if going to ECS 95 poly diff bushings will eliminate the whining sound or if it's being transferred from the subframe as well and changing out the diff bushings simply won't help. Any advice?

[aerobod]

You could always swap just the diff bushings back to OEM and leave the Delrin ones in the subframe, as they will be the most beneficial for handling if that is the main aim of using solid bushings, assuming NVH from a suspension perspective is acceptable.

[jb-slow]

You could swap the diff bushings to powerflex inserts, I didn't hear any change with mine. The diff won't change any handling abilities, so you could simply go back to stock also.

[Potty Mouth]

Originally Posted by jb-slow

You could swap the diff bushings to powerflex inserts, I didn't hear any change with mine. The diff won't change any handling abilities, so you could simply go back to stock also.

I just got a response back from RRT racing out of VA, for street cars, they don't like or recommend any Urethane or Delrin, the aluminum inserts on Urethane ones wear and cause movement in time and the Delrin are too loud for most. Stock is pretty much the only option. I'm swapping back. Did you see any noticeable improvements with the inserts?

[jb-slow]

Originally Posted by Potty Mouth

I just got a response back from RRT racing out of VA, for street cars, they don't like or recommend any Urethane or Delrin, the aluminum inserts on Urethane ones wear and cause movement in time and the Delrin are too loud for most. Stock is pretty much the only option. I'm swapping back. Did you see any noticeable improvements with the inserts?

A little less slop, I was just looking to firm things up a bit without making new noise since it's my daily and only a track toy about once a month. The powerflex stuff fit the bill perfectly.