Comprehensive Steering Information Thread

[old///MFanatic]

I hear sound while turning my car and steering fluid is leaking from the boot, most probably steering rack gone bye bye? I don't track my car and daily it, should I go with stock or yellow?

Well depending on your DME version (car build date) you might not want to mess with the ratio. You don’t have your info posted in user info.
If your version is unable to code to CSL/ZCP rack setting then don’t even mess with it imho. Stay stock.

[Mr.wReckless]

How difficult is the shim install with the pump on the car? Also will I have to replace all the fluid?

I've done it a couple of times, and fluid will leak out yes, be prepared to catch it as the reservoir will drain. The valve/piston itself needs some persuasion to come out of the pump, I use a couple of magnets to a small socket that fits inside the pump that I push in then quickly retract so the valve spring will help push the valve/piston out.

Regards

[bullet0770]

I hear sound while turning my car and steering fluid is leaking from the boot, most probably steering rack gone bye bye? I don't track my car and daily it, should I go with stock or yellow?

[Obioban]

How difficult is the shim install with the pump on the car? Also will I have to replace all the fluid?

Not difficult.

Most of the fluid will leak out.

[lvm3sm46]

How difficult is the shim install with the pump on the car? Also will I have to replace all the fluid?

[Thoglan]

Any issues so far with purple tag?

Nope, my m3 is out of commission atm rebuilding the motor. Never ran into issues prior though. Set of square 9.5 wheels arriving mid March so will see if that starts causing issues. I am not a very aggressive driver on the street however, so my experience could be different.

That being said, I kept my original rack so if it started playing up I'd just put the old one back in. The difference between the two racks was not that huge.

[S3diment]

S3diment 2002 mk20 car here, if you have a rhd car a solid steering coupler could be nice. Installed on mine but yet to drive with it. I also have a purple tag rack, no issues with it but yet to take it on track with the new rack nor do I run an aggressive wheel set up (yet).

Any issues so far with purple tag?

[Volke]

I wish I could remember his forum handle. I know he was from Norway or Sweden or something like that. He posted in the DME threads a bit, and drove a 318ti or 325ti compact. Terraphantm might remember him.

Us MK20 guys need to pool some money together to throw at whoever can figure this out. This NEEDS to happen.

[ChipperM3]

Us MK20 guys need to pool some money together to throw at whoever can figure this out. This NEEDS to happen.

The DSC unit uses the output of the steering column rotation sensor to calculate which direction the wheels are pointed. Changing to a quicker rack will cause the DSC unit to assume less steering angle than is actually applied, and will not match the lateral G measured by the yaw sensor, so the car may think something is wrong and cut power / apply brakes as it thinks necessary.

The MK60 can be toggled to the ZCP steering settings when 50 mm/rev rack is installed and everything will work perfectly. I'm not aware of any such setting on the MK20.

There was someone on the old M3 Forum working on a dualCAN gateway that could be plugged in between the steering column sensor and DSC unit, to intercept the column sensor signal and scale it as necessary to maintain proper DSC function. Unfortunately, I don't remember his username. If anyone else has the skills to do it, the trick is to scale the column sensor output as follows:

[column sensor output] * [new rack mm/rev] / [stock rack mm/rev] * [stock knuckle steering arm length] / [new knuckle steering arm length]

[Obioban]

Been reading through this and don’t have a definitive answer on what a viable steering upgrade would be for a 2002/MK20 car. Anyone provide insight?

If you drive with DSC on, stay with the stock rack. You could bump up feel and heft a bit by shimming the regulator.

[Thoglan]

S3diment 2002 mk20 car here, if you have a rhd car a solid steering coupler could be nice. Installed on mine but yet to drive with it. I also have a purple tag rack, no issues with it but yet to take it on track with the new rack nor do I run an aggressive wheel set up (yet).

[S3diment]

Been reading through this and don’t have a definitive answer on what a viable steering upgrade would be for a 2002/MK20 car. Anyone provide insight?

[Radekxpl]

Thank you for confirming. I added the picture to post #3.



You can reuse the outer tie rods on you car unless you're looking to refresh them in which case I'd pick up a set of outer tie rods from FCP Euro and have a lifetime replacement warranty on them in case you ever fail a tie rod ball joint or bend one somehow.

Glad to contribute to this awesome informational thread 👍😊


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[Volke]

It turns out that there is alternative to ZHP Yellow tag rack, The 7852 974 678 Purple Tag has the same exact spec as ZHP 712 Yellow tag, check out comparison video between the two.

Purple Tag



Rack Rate = 50 mm/turn

Turns Lock to Lock = 3

Total Rack Travel = 150 mm

Linear

Thank you for confirming. I added the picture to post #3.

Thanks a lot. So I'll purchase just the rack with the inner rods included and I'll buy the outer ones separately. I also know that there is a difference but when I've contacted the rackdoctor and ask them if they can sell the rack with outer rods for m3, they answered that the outer rods are interchangeable among the e46 platform. Thanks for the confirmation.

You can reuse the outer tie rods on you car unless you're looking to refresh them in which case I'd pick up a set of outer tie rods from FCP Euro and have a lifetime replacement warranty on them in case you ever fail a tie rod ball joint or bend one somehow.

[old///MFanatic]

That’s interesting, would definitely like see comparison between both installed and operating on actual car, highly doubt though that’s going to happen as it’s not 5 minute swap to change racks just to do comparison. But that could very well the case. Also I’m not sure what trim dictated this purple tag rack to be installed in particular car by bmw as not all 325/330 had 13:7:1 ratio.

Hmm it's been a while since I researched all this but kinda remember all 330s moved to 13.7:1 around 04/'01. But who knows anymore. I will add that the late 2000-2001 had a bunch of mixed changes in the racks from BMW and retrofits by BMW for overboost feel.
But the one pictured was built in later '04 model run. July of 2004 it appears