Comprehensive Steering Information Thread

[Taz]

Anyone know if a rack from a UK Z4M Coupe would fit our US E46 M3? Are the racks the same on the U.S. and UK Z4M Coupes?

UK drive on the wrong side of the street. Wait... right side.
No, racks are not the same as the steering wheel is in the wrong place.

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[bigjae46]

Anyone know if a rack from a UK Z4M Coupe would fit our US E46 M3? Are the racks the same on the U.S. and UK Z4M Coupes?

It’s probably going to be RHD…so my guess is no.

[Advorsor]

Anyone know if a rack from a UK Z4M Coupe would fit our US E46 M3? Are the racks the same on the U.S. and UK Z4M Coupes?

[Ubaderb]

Anyone have a shim on hand that they can measure for me? Trying to see if I can source some for myself.

[digger]

If some is good more is better?

[YoitsTmac]

I hadn't. Instant buy. Thanks for linking

[stephen]

Wondering if anyone here has heard of the new steering rack LPSR in Australia plans on releasing for the E46. Promises 2.5 turns LTL.

https://www.steeringlpsr.com/product-page/black-label-black-tag-lhd

[terra]

From what I measured I think its a mistake..I specifically measured multiple z3 racks from multiple cars (couple 1.9, 2.5). They were all the same. The real puzzling one to me is the z4m coupe vs roadster rack. I measure both and again they were identical (50mm\rev), but in this case I believe even BMW reports the coupes as having a quicker steering ratio. Not sure what that's about.

The OP of this thread needed photos to update the post and avoid misinformation but I didn't take any at the time.

Yeah that one is a mystery to me. BMW claims 13.7:1 vs 12.8:1 for the roadster vs coupe. As far as I know suspension is otherwise identical between the two so a geometry change wouldn’t explain the steering difference.

A hypothetical 53.5mm rack would get you to that ratio difference (assuming 50mm = 13.7:1)

More confusingly, the first post indicates the tie rod to control arm distance on the Z4M is the same as the M3 (and longer than the non-M), which means a 50:1 rack should result in a 14.5:1 ratio.

[bigjae46]

You could just put on an underdrive pulley

Not the same. An underdrive pulley doesn't do anything to lower the system pressure. It spins the pump slower and increases the likelihood of cavitating the pump at low RPMs. The PS pump is a PD vane pump and those do not tolerate cavitation.

I'd have to do some math but I'm pretty sure the pump reaches the operating pressure fairly quickly. The shims lower the operating pressure by opening the pump pressure relief/regulator at a lower PSI which increases effort but avoids the low RPM cavitation.

[duracellttu]

I've always wanted to drive a car with a yellow or purple rack and see if it feels any heavier. My blue tag is pretty light.

You could just put on an underdrive pulley

[Ubaderb]

Send a PM to Volke (OP of this thread).

OP hasn't been on since March of last year.

[Obioban]

I've always wanted to drive a car with a yellow or purple rack and see if it feels any heavier. My blue tag is pretty light.

Shim it?

[D-O]

Anyone know where to source the power steering shims?

Send a PM to Volke (OP of this thread).

[lapoune]

53.5mm/rev stated in this thread post #3? Maybe it’s erroneous

From what I measured I think its a mistake..I specifically measured multiple z3 racks from multiple cars (couple 1.9, 2.5). They were all the same. The real puzzling one to me is the z4m coupe vs roadster rack. I measure both and again they were identical (50mm\rev), but in this case I believe even BMW reports the coupes as having a quicker steering ratio. Not sure what that's about.

The OP of this thread needed photos to update the post and avoid misinformation but I didn't take any at the time.

[9kracing]

I've always wanted to drive a car with a yellow or purple rack and see if it feels any heavier. My blue tag is pretty light.