Rearend feels loose and uncontroled.

[Lambobimmer]

I had this same problem with my E46 M3 and it turned out to be a severly bent rear lower control arm. It was bent when the tow driver tied down the car using the lower control arm. I checked everything and nothing looks bent or loose.

When I am in any gear and I go WOT the front seems to pull to the right. Normally, at WOT the rear will sit down and the front come up evenly and that is not the case with my car right now.

The rear end also feels unstable. It doesn't feel loose but unstable is about the only way I can explain it.

I have the following suspension mods:

BMW Performance Suspension - about 6 months old
ARC-8's with Michelin Pilot Super Sports
Front alignment pin delete for negative camber

[TT1351]

My guess is that its the poor design of the rear subframe mounts. Many are replacing them with M3 subframe bushings, and the difference is day and night. Gone is the squat and wallowing feel, transformed into a very solid, planted rear end. In my opinion ride quality is enhanced, not degraded. Check out HP Autowerkes for the mounts, they also rent a removal/installation tool which is well worth it. I tried doing the McIver thing and create my own with limited success, and much frustration. That should fix your rear end complaint.
Fran

[Lambobimmer]

Originally Posted by TT1351

My guess is that its the poor design of the rear subframe mounts. Many are replacing them with M3 subframe bushings, and the difference is day and night. Gone is the squat and wallowing feel, transformed into a very solid, planted rear end. In my opinion ride quality is enhanced, not degraded. Check out HP Autowerkes for the mounts, they also rent a removal/installation tool which is well worth it. I tried doing the McIver thing and create my own with limited success, and much frustration. That should fix your rear end complaint.
Fran

This is my thought as well. My best guess is the added traction is causing this issue. Hopefully the M3 bushing will fix this problem.

[Dackelone]

Start by having your alignment checked. Could be something in the rear out of spec. Like too much toe-out.

[Lambobimmer]

Just did an alignment. About -.80 camber in the front and the rears are spot on.

[Dackelone]

Originally Posted by lamboworld

Just did an alignment. About -.80 camber in the front and the rears are spot on.

But what about the rear toe? When I mounted my PS3's the shop checked my alignment... the left rear toe was slightly out of spec. They dialed it back in - my car felt so much better at high speeds after that. Also on nump steer the car drove easier. I think its your rear toe. Or... it could even be one of your rear bushings that are worn. ???


I have been thinking of the M3 subframe bushings for my car. Mainly because when you really throw the car (hard) around corners... it is hard to figgure out how much oversteer you will get. Twitchy is the word that comes to mind. I want something more precise.

[TT1351]

Trust me its the bushings!
Fran

[MilehighM3]

Definitely the bushings. I have similar mods plus more in mine and the bushings make a big difference. Also check out the powerflex full replacement bushings. They are fairly new and much better than just the filler bushing pieces they offered before. Much easier install than the M3 parts too. Similar if not cheaper as well

[akak1997]

I really wanted to do the M3 Rear Subframe bushing as well, but I've asked around, the labor involve is pretty expensive. The part itself isn't much... just the labor is killer.