Comprehensive Steering Information Thread

[terra]

I didn't find the change in weight to be tremendous (though it is noticeable). The reduced steering ratio did make a nice difference even in daily driving though. Just feels more appropriate for a sports car.

The heavier feel compared to a non-M with the same rack is going to be mostly due to the suspension geometry. E46 M3 has more caster, more camber, both of which work against you in terms of steering weight. If you want something with the same ratio, but less weight - the 325i rack ("purple tag") might be worth considering, but I don't have first hand experience with that one. I'm also not quite sure where the actual ZCP rack lies in comparison with the ZHP rack when installed in an M3.

[snaponbob]

Interesting responses.

Before I even post the following question, it sounds STUPID !!! I've been autocrossing and now tracking since 1981. Knowing how light old American road barge power steering was/is (i.e. 60s Chryslers and GMs), I find most contemporary p/s systems firmer, and sometimes with very good feel. So, why is even heavier steering than stock E46 M3 beneficial? If firming the system results in ACTUAL improved feel, that's good. But, making a system require more muscle sounds like a fine way to get tired faster !!! ( I guess that goes to BBR Tunings' comment about endurance racing.) I can't imagine why people do p/s deletes on 36s and 46s other than for the minor weight savings.

I am recovering from rotator cuff surgery (10 days ago). I have the M3 on stands for the winter with a laundry list of changes before Mar/April track events start up again. All the trim in the front is off for a condenser delete and some ducting, oil pan is off to check things inside and thus the entire subframe is out. So, now is the time to gather info before stuff starts going back together once I can do that (mid/late Feb I hope).

[old///MFanatic]

Is the heavier feel a function of a mismatch of steering pumps?
Given all I have read, I am not clear as to whether or not one rack is "quicker" than the other?
Is there a tangible benefit of one rack over the other?

The ZF .712 “yellow tag” (sometimes called zhp) rack is a quicker ratio than the stock E46 M3 (non-CSL/ZCP). The internal torsion bar, and internal pressure valve are said to also give it a heavier feel compared to other same stock E46 ratios.

[BBRTuning]

Hi all. I was sent here from bimmerforums.

I have an 04 M3 that was an autocross car, but it's a slug against the newer M3 that run in the same class. So, after autocrossing since 1981, and loving the car over the past 4 seasons, I migrated to track days and SCCA Time Trials. The car is well setup and is an overdog in my TT class.

When I first started running solo, I climbed the learning curve after 5 seasons in E36s. One change I made mid first season was a ZHP rack. My first impression was how much heavier the steering felt, but couldn't definitively define the difference in response through slaloms and switchback sweepers. I didn't bother me enough to swap the M3 rack back in. Well, the entire front subframe is out so everything is laying on the floor. So, now that I am going into the 3rd season of track use ---

Is the heavier feel a function of a mismatch of steering pumps?
Given all I have read, I am not clear as to whether or not one rack is "quicker" than the other?
Is there a tangible benefit of one rack over the other?

I much prefer heavier steering, to the point of swapping to a Z3 rack and I then shimmed the power steering pump to reduce assist.

Early 330i racks had the same quicker ZHP ratio but with a much lighter feel, enough so that some early owners complained and BMW replaced the racks. I have one of these sitting in my garage, PM me if you’re interested. They’re sometimes preferred by E46 endurance racers for obvious reasons.

[snaponbob]

Hi all. I was sent here from bimmerforums.

I have an 04 M3 that was an autocross car, but it's a slug against the newer M3 that run in the same class. So, after autocrossing since 1981, and loving the car over the past 4 seasons, I migrated to track days and SCCA Time Trials. The car is well setup and is an overdog in my TT class.

When I first started running solo, I climbed the learning curve after 5 seasons in E36s. One change I made mid first season was a ZHP rack. My first impression was how much heavier the steering felt, but couldn't definitively define the difference in response through slaloms and switchback sweepers. I didn't bother me enough to swap the M3 rack back in. Well, the entire front subframe is out so everything is laying on the floor. So, now that I am going into the 3rd season of track use ---

Is the heavier feel a function of a mismatch of steering pumps?
Given all I have read, I am not clear as to whether or not one rack is "quicker" than the other?
Is there a tangible benefit of one rack over the other?

[DJAM3]

Pretty much my experience. I was
prepared to test it out and if it was intervening on the street I would just swap back. On track the dsc gets turned off anyway cause it's rubbish. But to my surprise despite all the warning on the forums, nothing. It's been on the car for about a year now and no issues. Since then I have run square 9.5j 255 and a solid steering coupler, still nothing.

I'm in the process of installing a yellow tag on my '01 to try it out for myself. Worse case I'll turn the DSC off or swap back to the green tag. Just did the rod bearings so it will be a while before I can push it.

[BlAikenstein]

What’s the opinion on rebuilding racks? I bought an unknown mileage ZHP rack I’ve been waiting to install and was planning to rebuild it with a gates seal kit. It feels good and tight turning by hand so I’m kinda just wanting to throw it on and enjoy it before winter. I’ve got a new pump I’m planning to shim to 25% as well.

[terra]

The 2004 I just recently bought has a green tag on the rack, Does this mean it was changed at some point?

Green tag is the stock non-ZCP rack

[bullet0770]

ordered the bimmergeeks cable, I needed to check codes and bleed brakes as well.

[lvm3sm46]

The 2004 I just recently bought has a green tag on the rack, Does this mean it was changed at some point?

[bullet0770]

2005 is MK60, so you can code it to expect the yellow tag rack.

If a faster rack is an upgrade or a downgrade is up to you— every steering ratio is a compromise.

Thanks for your reply, My car is stock and I don't have access to code. Maybe leave it stock is good option for me or buy INPA?

I wouldn't say the rack difference is earth shattering. Like Ian said earlier, probably get more of what you're looking for just by shimming the pump.

That being said, if you can code the car for CSL rack, have access to a rack for a good price, can install it yourself to save on costs, then I don't see why not. But it is a MINOR improvement, and a bit of a ballache to install.

Great, you have later DME that can accept coding. You could code for the ZCP/CSL rack ratio.
You could even code at same time for the “M-Track” mode that allows less intrusive DSC(allows more tire slip).
The third “active/non-active” setting is for brake bias if you had the larger CSL/ZCP brakes.

Thanks for your reply.
I can do all the mechanical stuff but don't have access to code the car. I read that we can buy the software but the old one's were not working. Do we have a link where I can buy (INPA?)

[Daniel]

Digging thru the archives, my current (e46 M3) inner/outer tie rods can be used when I install my 712 yellow tag rack. Can anyone double confirm this? Any other things I’m missing for the 712 install?

[old///MFanatic]

I have a 2005 M3

Great, you have later DME that can accept coding. You could code for the ZCP/CSL rack ratio.
You could even code at same time for the “M-Track” mode that allows less intrusive DSC(allows more tire slip).
The third “active/non-active” setting is for brake bias if you had the larger CSL/ZCP brakes.

[Thoglan]

so worth having a yellow tag one in pace of the stock? mine is all street driving. My car is 2005

I wouldn't say the rack difference is earth shattering. Like Ian said earlier, probably get more of what you're looking for just by shimming the pump.

That being said, if you can code the car for CSL rack, have access to a rack for a good price, can install it yourself to save on costs, then I don't see why not. But it is a MINOR improvement, and a bit of a ballache to install.

[Obioban]

2005 is MK60, so you can code it to expect the yellow tag rack.

If a faster rack is an upgrade or a downgrade is up to you— every steering ratio is a compromise.