Ground Control Coilover Conversion Kit

[SECRET M]

anyone else running these and suffering from a bushing-like noise near full lock on each side after a very low-speed compression of the front suspension (speed bump at an angle, parking lot entry at an angle etc).

never in my 10+ years of working on cars have a heard suspension noise like this. something sounds wrong.

[vuudoopham]

Hey did you ever figure this out? I have the same noise on my car. I am using their coilover kit that keeps the EDC.

[M3SQRD]

Could the noise be coming from the sway bar end links? With the suspension compressed and the wheel turned at full lock I wonder if it's the ball running out of its range of motion and hitting a "hard stop"? You could unbolt the links and go for a short drive. If the noise goes away then you know the cause; if not, at least you've eliminated one possible source.

When your car is on a lift does the spring unseat itself from the upper mount at full droop? I remember reading in a different thread that short springs are used without helper springs in this kit. I wonder if the spring is partially seating-unseating itself at full steering lock? If the spring is unseating itself at full droop I'd recommend adding helper springs to the setup, even if this doesn't address your noise issues.

[JM3]

Originally Posted by dbarnes

Could the noise be coming from the sway bar end links? With the suspension compressed and the wheel turned at full lock I wonder if it's the ball running out of its range of motion and hitting a "hard stop"? You could unbolt the links and go for a short drive. If the noise goes away then you know the cause; if not, at least you've eliminated one possible source.

You are on the right track.

This is usually a result of the end link clamp not being lined up in the same position as stock.

Check that first, correcting the orientation usually solves everything. If not keep reading!

Originally Posted by dbarnes

When your car is on a lift does the spring unseat itself from the upper mount at full droop? I remember reading in a different thread that short springs are used without helper springs in this kit.

The stock EDC front struts droop very far, to accommodate a long soft spring.

To lower the car you need a shorter spring.

To prevent coilbinding, you need a spring with a limited number of coils between the spring.

To have a limited number of coils between the spring, you cannot add extra coils from a tender spring.

Therefore, in order to have adequate spring travel, you cannot use a tender spring.

(the corrollary argument is that if you have inadvertently limited travel, you CAN use a tender spring.)

Originally Posted by dbarnes

I wonder if the spring is partially seating-unseating itself at full steering lock?

Impossible. This the technique to confirm: Put your finger in the spring and steer the wheel. Your finger will hurt because the entire corner-weight of the car is still on the spring (and your finger)

Originally Posted by dbarnes

If the spring is unseating itself at full droop I'd recommend adding helper springs to the setup, even if this doesn't address your noise issues.

There are many posts reporting this ADDS noise.

Helper springs touch coils metal to metal, by definition.

Metal to metal makes noise.

I have attached different pictures that have been used to help shops correct their installation of GC sway bar links. You are welcome to take pics and email them to GC, and someone there can help you figure it out, just like in the pics below.













click for email

[M3SQRD]

Good explanation on how to address all potential sources of noise!

I used the "seat-unseat" terminology for a lack of a better word - I guess what I was tring to describe was a spring binding then twisting as the strut is turned so perhaps "stick-slip" would have been better? Correct, a spring would not unseat as long as there is weight of the car on the spring and, thus, compressing the spring.

At no point was I suggesting the use of a tender spring because that would increase the effective length and solid height of the spring stack. Agreed, adding a helper spring would create a potential new noise source.

[tha_good_life]

I recently told my friend at BMW service to grease up the front suspension due to noises. Ever since, my car is noiseless and feels a lot better.

[quads]

Originally Posted by bapesta206

I recently told my friend at BMW service to grease up the front suspension due to noises. Ever since, my car is noiseless and feels a lot better.

Grease up where? springs? perches? sways?
The problem with grease is that it's a dust/dirt magnet and gets really nasty after a while.

[tha_good_life]

From my understanding, you have to lug the end links every so often. Now, i'm not sure what my mechanic did but it made a huge difference in suspension quality.

Originally Posted by 4sevens.com

Grease up where? springs? perches? sways?
The problem with grease is that it's a dust/dirt magnet and gets really nasty after a while.

[JM3]

Originally Posted by 4sevens.com

Grease up where? springs? perches? sways?
The problem with grease is that it's a dust/dirt magnet and gets really nasty after a while.

The front sway bar bushings make a lot of noise, even on completely stock M3's. Definitely lube these. If you just wipe of the excess grease, there doesn't seem to be a dirt problem.

In my opinion, the rigidity of the chassis, especially the M3, has exaggerated all of the traditional noise sources that used to go unheard.

I have talked with some smart guys, and we also believe that the strut braces attaching to the cowl make previously unheard noises more prominent.

Here is an ongoing thread about noise from completely stock M3's:

http://www.m3post.com/forums/showthread.php?t=427354