Cracking sound (bent sway bar ?)

[gnjax]

Hi !
I started noticing a few weeks ago my e92 m3 having a loud 'cracking' sound when close to full turn coming from the passenger side wheel well, especially under some acceleration or uneven surface. This not a subtle sound, I can almost feel it to the point it makes me physically cringe. Sounds like something just broke everytime.
I lifted the car and noticed the sway bar is badly scratched on one spot, almost polished from what I believe is contact with the tie rod.
With straight wheels, the distance between the tie rod and the sway bar is 2 times shorter on passenger side than driver side. I'm not sure if that's what causing this noise (Not reproductible with the car lifted) but something is wrong in there.
The thing is I can't see anything bent from the naked eye.
I don't have much experience when it comes to suspension problem, any ideas on what my next step should be to figure out the problem ?

[DukeofAlexandria]

Originally Posted by gnjax

Hi !
I started noticing a few weeks ago my e92 m3 having a loud 'cracking' sound when close to full turn coming from the passenger side wheel well, especially under some acceleration or uneven surface. This not a subtle sound, I can almost feel it to the point it makes me physically cringe. Sounds like something just broke everytime.
I lifted the car and noticed the sway bar is badly scratched on one spot, almost polished from what I believe is contact with the tie rod.
With straight wheels, the distance between the tie rod and the sway bar is 2 times shorter on passenger side than driver side. I'm not sure if that's what causing this noise (Not reproductible with the car lifted) but something is wrong in there.
The thing is I can't see anything bent from the naked eye.
I don't have much experience when it comes to suspension problem, any ideas on what my next step should be to figure out the problem ?

2 questions…
- Do you have EDC on the car?
- Did you visually inspect the shock for fluid/caking around the boot? (Indicator the shock is bad)

I'd guess a bad shock and you'll need to replace.

-Duke

[Scrippy]

Originally Posted by DukeofAlexandria

2 questions…
- Do you have EDC on the car?
- Did you visually inspect the shock for fluid/caking around the boot? (Indicator the shock is bad)

I'd guess a bad shock and you'll need to replace.

-Duke

Hey Duke just curious why you asked if he had EDC? Is something tighter clearance wise with EDC compared to non EDC? I'm just asking for things to beware if as I have EDC.

[DukeofAlexandria]

Originally Posted by Scrippy

Hey Duke just curious why you asked if he had EDC? Is something tighter clearance wise with EDC compared to non EDC? I'm just asking for things to beware if as I have EDC.

I've heard in very rare circumstances that EDC can go haywire and put different settings onto different sides of the car. Most of the time when the module is bad it breaks/faults both shock towers but figured it was worth asking/mentioning.

I highly doubt it's EDC, because even in the hardest/stiffest mode it doesn't affect height, just shock damping control. Also, the amount he's specifying, I wouldn't rule out a broke spring/spring perch. The front springs are pretty stiff and even with a bad shock I wouldn't expect a 2" drop as op described.

-Duke

[spammysammich]

Broken strut top mount on the passenger side?

[gnjax]

Thank you for the answers !
I do have EDC on this car, most of the time I drive on the stiffest settings.
I will lift the car again today as I have something else to do under there and check the shock thoroughly. I'll have a look at the top strut mount as well. I will post my findings

[gnjax]

Ok I checked today and the shock looks fine, can't see any fluid leaking around or excessive gunk accumulation compared to the other side. the top strut mount is fine too.
Also I checked more accurately and the tie rod and sway bar are only closer horizontally (by about 1inch), but not vertically

[spammysammich]

What are your wheel and tire specs?

[gnjax]

219m wheels, tire specs are stupid (225/35 R19 and 255/30 R19) cause I had to change them to register the car in EU (was an US import). Didn't run much on those tire, just waiting for them to be shot to go back to the bigger p4s it had before

[ksc]

Hey man, please post a sound test.

I had a sound: on almost full lock left or right, I hear two quick, loud, metallic sounding "crack crack" or "pop pop"

I checked everything (was not and am not an expert by any means), and a shop found out it was the bottom flex plate (the one under oil pan). Perhaps a bit bent after 11 years, or just not right enough, but it is probably the former.

They added washers between the subframe and the flex plate, tightened it well, NO MORE SOUND!!

Then it came back after a couple months.

So, I tightened the plate well, and sound is GONE even till now.

I bought a new underbelly flex plate and have yet to out it on, but I will and I'll check if the sound is still there.

For now, it seems that tightening the bottom flex plate fixed my issue - the shop suspects that since the subframe bends on turning the wheel, the sound happens.

Of course, there could be many other possible causes, such as struts/hats, but try this out first. It's easy. Tighten everything on the bottom belly plate well. Also, please post a sound test so I can let you know if this was the sound I was hearing. The sound I had been hearing would make me cringe. It sounded like a metal would snap every time I full lock, slowly, and it was also not reproducible on the lift. I'll report back as well once I put on the new flex plate.

[drrust]

When you raise the front end and turn the wheel, does anything touch the sway bar? That bar is more likely to break before it bends (hardened steel). Also compare to other side of the car.

Check your front tension arm bushings . Those are wear items and can make some noise.