[iqraceworks]

I installed the M3 rear controls arms and Whiteline black rear subframe bushings in my 07' 335i a few weekends ago.

The think drives great, handles much better, and the rearend of the car doesn't feel like it's walking around any more.......but sometimes I can notice some more vibration in the rear of the car, especially if I get on the gas hard from a dead stop. But as soon as the rpms get up over around 3,000 or so....it all smooths out and it's gone.

Is this normal when you get rid of the soft oem bushings and install the harder poly bushings with the aluminum inserts.

I don't think anyone would notice is unless I point it out....but I can feel it. Just wondering. Thanks!

[Tambohamilton]

Sounds normal. This is the NVH from firmer bushings that BMW didn't want you to feel, so they specced the crazy soft ones that you just removed.

[feuer]

Upgrading some will expose the weakness of others, especially pronounced on 13 year old vehicle. Maybe: wheel hop? Center bearing on drive shaft? Over inflated tires?

[iqraceworks]

Originally Posted by feuer

Upgrading some will expose the weakness of others, especially pronounced on 13 year old vehicle. Maybe: wheel hop? Center bearing on drive shaft? Over inflated tires?

Actually...it hooks up great now...no wheel hop at all. I guess it could be a driveshaft bearing....it's just a very slight vibration bi can feel, but it goes away after a second or two. The tires are brand new.....running about 35psi in the rears. .

I'm guessing that stiffer bushings are going to transfer more vibration and harmonics... .that's just par for the coarse.

[Soravia]

What about your exhaust? I just had to re adjust the muffler connection at the clamps. It was hitting the braces for the E91 wagon (also X1). Not sure what other things you might hit, like heat shield? It comes on at low RPM such as idle or slowing down to a stop in gear.

[iqraceworks]

The only time I can feel it is when I'm slightly on the throttle (not idle, not WOT....just rolling into it nice and easy)......it could be a driveshaft u-joint or bearing issue, but I don't know why those parts would go bad at the exact same time I put new bushings in. It's not exhaust or a heat shield vibration.

I'm assuming that with stiffer su frame bushings, and with the M3 rear arms that have bearing instead of soft rubber bushings in them.....some added vibration is normal....right?

At highway speeds there is no vibration....And at idle there is no vibration. The only time I feel it slightly is when I'm taking off from a stop....and at around 3,000rpms it goes away and never comes back.

[Tambohamilton]

Originally Posted by iqraceworks

The only time I can feel it is when I'm slightly on the throttle (not idle, not WOT....just rolling into it nice and easy)......it could be a driveshaft u-joint or bearing issue, but I don't know why those parts would go bad at the exact same time I put new bushings in.

They haven't necessarily just chosen this time to give up; they've probably been wearing and making these vibrations for a while, but now they're being transmitted to the cabin through the stiffer bushings, much more than they were with soft bushings.

[iqraceworks]

Originally Posted by Tambohamilton

They haven't necessarily just chosen this time to give up; they've probably been wearing and making these vibrations for a while, but now they're being transmitted to the cabin through the stiffer bushings, much more than they were with soft bushings.

Good point. I guess I might pull the drive shaft out and have it checked out. With over 100K on it, I'm guessing the u-joint and/or center bearing may have a little play in it?

I did a little more driving around this morning....it seems speed related, not RPM related. I can feel it around 15-20mph, before and after that it's gone. RPMs don't really matter....but speed does.

I guess that would point to something driveshaft related maybe?

[Tambohamilton]

Yeah, sounds about right. Driveshaft or diff, at a guess.

[Soravia]

Originally Posted by iqraceworks

Good point. I guess I might pull the drive shaft out and have it checked out. With over 100K on it, I'm guessing the u-joint and/or center bearing may have a little play in it?

I did a little more driving around this morning....it seems speed related, not RPM related. I can feel it around 15-20mph, before and after that it's gone. RPMs don't really matter....but speed does.

I guess that would point to something driveshaft related maybe?

Center hanger bearing needs press. Flex Disc aka Guibo cracks staring at 60k miles and need a large pry bar to work it out against pressure from drive shaft. Check my thread in xDrive section replace all three

I have entire M3 sub frame with all M3 arms and bushings, save the damper and spring arm. Should have switched to M3 spring arm and damper, too.

No vibrations. Even after rear diff vibe absorbing weight was removed.
I will see if there gear whine on highway speed

[iqraceworks]

Besides the u-joint and center bearing, anything else that could be causing the vibration? At highway speeds...it's smooth as can be. I only feel it at slow speeds in 2nd gear. Never felt anything before the new bushings and M3 arms.

[iqraceworks]

****UPDATE****

Well, I think I found out what I was getting that vibration at slow speeds after I installed those rear subframe bushings. I decided last night I was going to pull the driveshaft out and have it balanced.....after I pulled the exhaust, and the heat shields....I noticed what was wrong.

I had installed the carrier bearing upside down....

Luckily it was an easy fix. I can't believe that with the driveshaft being out of alignment like that, it only had some vibration at slow speeds...but nothing at highway speeds.

Well....at least that stupid mistake on my part was an easy fix, I really wasn't looking forward to pulling the driveshaft out

[feuer]

It was one of my guesses but what was the reason for you removing and reinstalling the drive shaft central bearing for?

[iqraceworks]

Originally Posted by feuer

It was one of my guesses but what was the reason for you removing and reinstalling the drive shaft central bearing for?

When I dropped the rear subframe ,I unhooked the driveshaft from the back of the transmission...also had to remove the carrier bearing.