Car feels/drives very 'nervous'

[CorvallisBMW]

I've been fighting these symptoms for a while in my convertible and I haven't found anything that I thought could be the cause. Basically the car drives like it's 'nervous'; it doesn't like to return fully to straight after turning, there seems to be an horrendous amount of bumpsteer, and it just seems twitchy and impossible to drive with any sort of confidence or sense of relaxation. Driving in a straight line requires lots correction and it doesn't stay on the straight and narrow easily. Driving it hard scares the shit out of me because it's unpredictable, twitchy and quirky.

Some points on the car (all parts have roughly 10K mi on them):
H&R Convertible springs (lowered about 1.5" all around)
21mm/15mm OEM bars with urethane bushings
Bilstien shocks
Kmac camber/castor adjustable strut mounts
IE adjustable RTA bolts w/ OEM bushings
All news bushings, balljoints, CAs, M3 CABs, RTABS, subframe bushings, every single suspension piece replaced with OEM rubber.
Full 4-wheel alignment done only 3K ago
e36 steering rack
strut tower brace + lower x-brace

I fee like I've looked at all the likely culprits (CABs, ball joints, TABs, subframe bushings, etc) and everything seems to be in perfectly good condition (it should be after only 10K). I'm really at a loss here, anyone have some ideas? I know it's a convertible and the chassis is obviously less stiff than a coupe/sedan, but this feels more suspension related. Thanks in advance.

[KenC]

Did you remember to put the washer back between the spring hat and the strut mount?

[e30huh]

strut mounts

[e1_griego]

Who did the alignment?

[einstein57]

toss in some m3 cabs. The added caster will make it drive straighter and return to center after a turn. I'd also re-torque the rtab bolts to be on the safe side.

[KennyT]

If none of the parts were defective and the alignment was done correctly (no toe out) then it has to be the strut tops as others have mentioned.

[Hellabad]

I think the alignment is wrong. I see more and more crappy alignments every day. Some people are really getting ripped off.

Look up "toe plates" and check the toe yourself.

But everybody else is correct that you may not have the struts assembled correctly.

[e1_griego]

I think the alignment is wrong. I see more and more crappy alignments every day. Some people are really getting ripped off.

Yup, exactly what I was getting at.

[CorvallisBMW]

Did you remember to put the washer back between the spring hat and the strut mount?

Yes

strut mounts

Brand new Kmacs, forgot to add that

Who did the alignment?

Pacific Motorsport in Portland

toss in some m3 cabs. The added caster will make it drive straighter and return to center after a turn. I'd also re-torque the rtab bolts to be on the safe side.

Already running M3 CABs, I'll check the RTABs.

[Wh33lhop]

DEFINITELY check your alignment. If you don't want to shell out for toe plates at least have another shop check it (a lot of shops will put your car on an alignment rack for free and then only charge you to align it).

[CorvallisBMW]

Here are the alignment specs:

FR
camber: -1.2*
castor: 'spec e30 M3'
toe: .09"

FL
camber: -0.8*
castor: 'spec e30 M3'
toe: 0.08"

RR
camber: -1.4*
castor: n/a
toe: 0.11"

LR
camber: -1.2*
castor: n/a
toe: 0.07"

I also added some stuff to the first post that I left out, like camber plates and adjustable RTABs

[CorvallisBMW]

Added alignment specs... any ideas?

[jlevie]

Your alignment numbers look okay and I don't think they would explain what you are experiencing. It really sounds like the upper strut hats are binding. That could be from incorrect assembly, or binding in the upper strut bearing. It is possible that the steering rack could be binding, but that is pretty rare. You can usually tell in that is case by disconnecting the tie rods and cycling the steering from lock to lock.

[CorvallisBMW]

Thanks for the tip. I'm going to put the thing up in the air and check every nut and bolt, and also disassemble the struts to check for binding.

[KenC]

How many miles were on that rack?