[Canadiesel]

I'm planning to install solid M3 rear subframe bushings to eliminate some of the rear end slop and bumpsteer. I have no interest in using inserts or poly bushings.

Are there any issues with harmonics or fitment in the 335D? as opposed to a 335i etc.

[RL18]

Originally Posted by Canadiesel

I'm planning to install solid M3 rear subframe bushings to eliminate some of the rear end slop and bumpsteer. I have no interest in using inserts or poly bushings.

Are there any issues with harmonics or fitment in the 335D? as opposed to a 335i etc.

Well if your Harmonic dampener is in good shape, engine mounts and trans mounts are in good shape you shouldn't have any or very little resonance through out the frame or driveline.

I'd say it wouldn't be too uncomfortable.

What other suspension modification do you have?

[Canadiesel]

Originally Posted by RL18

Well if your Harmonic dampener is in good shape, engine mounts and trans mounts are in good shape you shouldn't have any or very little resonance through out the frame or driveline.

I'd say it wouldn't be too uncomfortable.

What other suspension modification do you have?

Stock M-sport suspension now. I'm replacing these subframe mounts with solid M3 bushings in anticipation of installing Ohlins road&track coilovers as suggested by the manufacturer. I don't want to amplify the mushy rear end any more than it is on stock suspension. Car has 45k miles so things are relatively fresh.

[RL18]

Originally Posted by Canadiesel

Stock M-sport suspension now. I'm replacing these subframe mounts with solid M3 bushings in anticipation of installing Ohlins road&track coilovers as suggested by the manufacturer. I don't want to amplify the mushy rear end any more than it is on stock suspension. Car has 45k miles so things are relatively fresh.

Ahhh I was gonna say, bilstein coilovers and m3 control arms took a bunch of slop from the rear end for me, as well as tightened the entire car up. I had the stock sport suspension though with a blown front passenger shock and 130k on stock suspension lol.

Of course the bushings and sway bars will add more stiffness. I feel like the stock electronic diff is the biggest culprit here for slop in the rear end. Once you add an lsd this car will handle a lot better cornering wise and be more predictable... the electronic diff does a good job in a straight line, but horrible in the corners.

[Yozh]

M3 in the E90 chassis came with rubber subframe bushings.

[Canadiesel]

Originally Posted by Yozh

M3 in the E90 chassis came with rubber subframe bushings.

Solid bushings though as opposed to the 335D rubber bushings with voids in them.

That's what I believe to be true at least?

[Torgus]

Can you not use solid aluminum?

[Yozh]

Originally Posted by Canadiesel

Solid bushings though as opposed to the 335D rubber bushings with voids in them.

That's what I believe to be true at least?

Forget M3 factory bushings, go with solid aluminum or Delrin If you are gonnna bother doing them. Or go lazy and use inserts.

[Canadiesel]

Originally Posted by Yozh

Forget M3 factory bushings, go with solid aluminum or Delrin If you are gonnna bother doing them. Or go lazy and use inserts.

I need at least some compliance so aluminum is out. Which delrin bushings are people using? No polyurethane?

[Torgus]

Originally Posted by Canadiesel

I need at least some compliance so aluminum is out. Which delrin bushings are people using? No polyurethane?

There is zero NVH with solid aluminum subframe bushings. The newer BMWs come with them from the factory.

https://www.turnermotorsport.com/BMW...frame-bushings

The only reason to use delrin is if you are not allowed to in your car class if racing: solid rear sub-frame mounts are designed around Grand-Am, BMW CCA, and other series' regulations where a solid metal mount cannot be used. These are derived from, and currently used in our own Turner E92 M3 racecars. Thick Delrin casings are used as the non-metallic solid bushing.

[Yozh]

I agree on the nvh comment. Solid subframe bushings remove all compliance. But that is the intent. You don’t want any compliance there. Look at F80. Solid. No nvh.

[Tambohamilton]

All these people saying 'no NVH increase' with aluminium rsfb need a reality check! Sure the increase in nvh may be completely acceptable to you, but that does not mean that there is no change. Another car having a solid mounted subframe is not evidence for the rubber mounts on ours being superfluous.

OP, I thoroughly recommend moving to a stiffer than standard rsfb, and the correct one for you entirely depends on your application/preference. Anything you do will stiffen the rear end significantly, bringing more noise into the cabin. Vibration and harshness are a lot more difficult to quantify without measurement, but of course they must also increase.

I have an e91 330d, with near stock non-sport suspension. I don't track my car. I don't do 'launches', etc. I do like a bit of spirited driving though; corners are my thing. I fitted OE M3 bushings, and am very happy with the result... But I can now hear the rear diff (mainly at lower speeds), driveline noises when engaging gears at a standstill, and rear brake pad clunk when reversing. These aren't a problem to me, but I would prefer not to hear them. The rear end is way more taut, but I haven't been in the back of the car enough to know if there is a difference in comfort. I'm still more than happy to have my 2yo son in the back, at least.

There are no issues with harmonics or fitment with the M3 bushings, but you will feel/hear more from the back end.

Having more power on tap, you may feel the need for something stiffer than I do, but I very much doubt you need it unless you're putting on sticky tyres and tracking the car.

[tryingtobebest]

I run M3 bushings for a long time along with solid RUBBER diff bushings from mfactory - absolutely love my setup, check in my posts I have throughout description of install!

Don't go aluminum man as none of my buddies who running them is happy with them

[nick///M3]

Had M3 bushings in the d carrier

Installed the M3 carrier with solid bushings and some other solid stuff

Love the set up in Greece terrible roads
Ohlins suspension

No added NVH !!!!!!