Steering in the Z3 and M Coupe/Roadster

[o2wji]

Can we discuss steering in the Z3 and M Coupe/Roadster?

My experience is mainly with the Z3M. There are two things I don't like with the steering in the Z3M:

1. Steering ratio is too slow
2. Steering is too light

What can be done to address these two items?

[BeltFed]

Z4m coupe rack will fix all that. (not sure if an easy swap or not for the Z3 platform)


It looks like the Z3M is 13.9:1 ratio.
From this thread: https://www.bimmerforums.com/forum/s...teering%20rack

Z4mcoupe is 12.8:1 ratio
From this thread: http://www.z4-forum.com/forum/viewtopic.php?t=67644


From what I understand is its a common upgrade for E46m people.

[328 Power 04]

Z3 non M steering rack may be what you're looking for. 2.7 turns lock to lock, and linear. So center is a bit faster and tighter.

[BimmerBreaker]

Z3 non-M 6 cylinder rack is what you probably want

Z4M rack good too but expensive

[pine1000]

Have you checked your alignment? It won't help the ratio, but this can affect how light the steering is.

[JoshS]

Z3 6-Cylinder steering rack and increased caster is what you are looking for.


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[JWin]

Isn't there a fitment issue with the non-M rack in M cars?

[328 Power 04]

No, simple drop in, and alignment.

[pine1000]

Z3 6-Cylinder steering rack and increased caster is what you are looking for.


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Are you suggesting to increase the caster by using the offset control arm bushings? I thought that was a no-no when using the stock M control arms since they already have more caster than Z3 control arms.

[JoshS]

Are you suggesting to increase the caster by using the offset control arm bushings? I thought that was a no-no when using the stock M control arms since they already have more caster than Z3 control arms.

Use camber/caster plates at the top of the strut. Move the strut top rearward for more caster.

[o2wji]

Thank you all for the feedback. I will look into the non-M Z3 steering rack.

My current front alignment:

Toe: 1/16" total toe in
Camber: -1.8 degrees
Caster: Ground Control plates set at max caster (most rearward position) If I recall, the Ground Control plates set at max caster has less caster than the stock strut hats. Is this true?

In general, what makes steering feel heavy or light?

[LannVouivre]

Caster, tie rod age, and whether power steering fluid is low.

[pine1000]

Is the steering light just when it is on center or even in a turn?

I'm asking because my car had light/vague on center steering when I got it. I ended up replacing all wear items in the suspension and steering system, but I think the main culprit was the steering shaft flex disc. It was worn and had a slight bit of play, that was hard to detect while the part was on the car but obvious when it was out of the car. The steering in my car is great now!

[rf900rkw]

Jeeez. Get the caster back to stock M settings and leave it alone. If you have less than stock, you end up with two things. One is too-light steering feel. Second is a dose of bumpsteer. If it's enough, the car will hunt and wander and twitch on uneven roads like a riced Civic. This could make you think the steering is slow, because you can't keep up with what it's doing next.

[JoshS]

Jeeez. Get the caster back to stock M settings and leave it alone. If you have less than stock, you end up with two things. One is too-light steering feel. Second is a dose of bumpsteer. If it's enough, the car will hunt and wander and twitch on uneven roads like a riced Civic. This could make you think the steering is slow, because you can't keep up with what it's doing next.

That too. He's totally right, I should have said that. 99% of the time, someone's complaint about how their 15+ year old car behaves is caused by something (or more than one something) that has worn out. Think about whether or not a brand new car would ever have felt the way you are feeling it. If not, then just put it back to stock, like new, and go from there.