Poly bushings for RACP/Diff.

[Cubieman]

Who is running poly bushings on their Differential and/or Subframe?
I am thinking of going to poly route but am not sure if that's such a great decision as the vehicle is strictly street driven, although it will see some light track of Auto X use someday.
I do not care if its a but louder and firmer, I don't want it crazy stiff though either, it seems like 80A would be the next step up from OE bushings, please correct me if I am wrong.
I need a basic education on the pros/cons of poly subframe/diff bushings and maybe some product suggestions from those who have been there and done that.
Thanks for any help as I am in the learning stage in regards to poly bushings on this vehicle.

[Obioban]

Big mistake. Big nhv penalty from poly diff bushings, negligible benefit. Poly subframe bushings are all problematic in one way or another.

[Cubieman]

I see, so OEM may be what I do, not opposed to that one bit.

[Robert's_BMW]

Who is running poly bushings on their Differential and/or Subframe?
I am thinking of going to poly route but am not sure if that's such a great decision as the vehicle is strictly street driven, although it will see some light track of Auto X use someday.
I do not care if its a but louder and firmer, I don't want it crazy stiff though either, it seems like 80A would be the next step up from OE bushings, please correct me if I am wrong.
I need a basic education on the pros/cons of poly subframe/diff bushings and maybe some product suggestions from those who have been there and done that.
Thanks for any help as I am in the learning stage in regards to poly bushings on this vehicle.

A lot of people run solid subframe bushings with negligible NVH increase (helps reduce subframe flex); however, every other bushing in the back should be OEM or else you will get a huge NVH increase. A few other posts in the past have described this.

[heinzboehmer]

I'm running poly subframe and poly diff bushings. They're not great. Plan on switching to solid subframe and OE diff soon.

[trigtm]

I have fresh OEM rear subframe bushing and poly diff bushings since new rear diff bushings are NLA outside of replacing the complete cover. I haven't noticed any additional NVH to be honest. Car feels great with that combo. I believe the poly diff bushings I have are only slightly harder than OEM rubber which I chose specifically.

[oceansize]

Just refreshed every bushing and ball joint on the rear end and went solid (CMP brand) subframe and (CMP brand) RTAB. OE everywhere else. No NVH increase.

[clawhamm3r]

I've got both poly, it's pretty much only N...don't notice any difference in VH. Next time I have to drop the subframe I'll probably go solid. Will probably leave the poly diff bushings because I don't mind listening to my diff sing lol.

[Johnvu]

I have AKG subframe and revshift poly diff and I honestly don't have much of an increase in NVH. However, my exhaust is pretty damn loud, which is probably a huge reason. The car feels amazing and so much more stable/planted.

[timmo]

It really depends on which poly bushing you use for the diff, but as a general rule of thumb no driveline mounts should be poly. I do have ECS Tuning poly diff bushings on my non-M and there has been negligible effect on NVH compared to stock, but the ECS bushings are real soft

[Nick_P]

I have solid subframe, diff and RTABs (Turner). There is some NVH, such as diff whine and sometimes very slight vibration in on/ off throttle at low speeds.

If you're sensitive to NVH go solid subframe and OE everything else as others have mentioned. For me it's a weekend/ fun car so if I were to do it all over again I'd still go with my current setup... hearing the diff whine a bit just adds to the drama

The rear end feels more responsive/ direct since going solid

[Zesty Bonanza]

I have revshift 80A poly differential bushings and did not notice an increase in NVH. My old rubber bushings on the differential were worn out causing a clunk or thump noise. I have Powerflex street bushings for subframe, FCAB, and RTAB. I think most of my cabin noise comes from tires in combination with from my CKS coilovers and the Powerflex bushings. The noise isn't very noisy to me or my wife. It is noisy when trying to speak in a phone call (using Bluetooth and AUX adapter) and microphone mounted near ignition key. The other party on the call hears a lot of extra noise and I have to yell. I don't often do calls in the car, but I now use a Bluetooth headset.

[STAATS]

+1 to solid Subframe and OE Diff and no NVH. Also have SDW RTABs, ECS Performance Monoball RSM and refreshed OE everything else in rear

[BMWahba]

Are you guys who are running OE Diff/Solid subframe combo running a rod joint lower control arm (camber arm) or OE bushing style? I've narrowed down my entire rear end refresh down except this one component. Unsure whether to go rod-end style here or OE. Any significant increase in NVH with this rear arm if going with a solid bushing style?

[oceansize]

Are you guys who are running OE Diff/Solid subframe combo running a rod joint lower control arm (camber arm) or OE bushing style? I've narrowed down my entire rear end refresh down except this one component. Unsure whether to go rod-end style here or OE. Any significant increase in NVH with this rear arm if going with a solid bushing style?

Finished my complete rear end a few months ago and went solid subframe from CMP, oe everywhere else, and my lower arca is this ground control with bearing which is really nice and heavy duty. I really like this setup and I came from poly in my subframe.