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ZHP Steering Rack Mod

113K views 281 replies 43 participants last post by  Bali 
#1 ·
I finally got rid of the piece of $hit overboosted steering in my '01 330i. Picked up used '04 330i ZHP rack & pinion for $250 and had a stealer do the install + alignment.
It's a night and day difference; the new rack feels solid and the car drives like a BMW should. Best mod I've done thus far :excited:

The ZHP rack & pinion part # 32136757650.
 
#60 ·
Oh lord. From now on anyone who gets anything zhp should just say, "I got a steering rack from it-which-cannot-be-named. Combined with a steering wheel from it-which-cannot-be-named and control arms from it-which-cannot-be-named I have changed the entire steering experience!"

And SeanC has had a zhp and non-zhp so Alex, Mango, and everyone else is out to lunch. You will not change his mind, and you shouldn't, because he has owned both and none of you others have. You just endlessly research part numbers and ETK diagrams. I too have owned both as well and concur with Sean's statements.
 
#61 ·
And SeanC has had a zhp and non-zhp so Alex, Mango, and everyone else is out to lunch. You will not change his mind, and you shouldn't, because he has owned both and none of you others have. You just endlessly research part numbers and ETK diagrams. I too have owned both as well and concur with Sean's statements.
yeah because doing research and confirmation of part numbers along with just about EVERY zhp owner and site confirms the racks are the same. but it's cool, what do we know when it's better to say I believe in the "ZHP Santa Claus" compared to facts. :rofl:

i'm not saying the car he drove doesn't feel better or different. I'm just saying the steering rack ratio is comfirmed in parts, publications and in full turn lock-to-lock to have the same ratio.

if you like to settle your deate, please call BMW with your 330ci-zhp VIN and ask them for a quote and part number. then report back with your findings. also have someone else call for any year 2002-2006 330Ci-zsp (non-zhp) and report back the part number they're ordering. i would do it myself but know you won't take my word for it.

everyone has already established it's the same ratio across the BMW community and forums. we do this for the benefit of others to save money and have correct info. if you are going to insist it's not correct then you have to do your small part to back this up. otherwise you're just being selfish wanting to say you have something unique. fair enough?
 
#74 ·
That's exactly what i mean. Everything, short of arms and shocks, is proven to be the same (by some respected members!), yet the feel is there. How come? It's not the arms, not the rack then, what is it? Maybe it's the sway bars... oh wait, it's not that either!
 
#75 ·
So Sean what are you saying now? You're on board with the 330s having the same 13.7 steering rack ratio but now suggest the internals and something else in the 330-zhp rack makes it better.
So when you need a replacement 330-zhp steering rack bmw doesn't make them anymore or you suggest they are all the same now? I really don't follow.

I can't say about the internals but do you really think BMW made a special rack run? Also without a replacement for the car? There are part numbers for everything else and with a cost.

I leave you with the term, "Occam's razor". It fits this best of any.
 
#76 ·
Simple question: What makes ZHP's steer the way it does? If you say it's the control arms and shocks, I don't buy that. Make me believe.

I don't know if BMW made a special run for the rack, but it could have as well been the Msports pack II internals in the regular 330 rack. Both were readily available when ZHP package was invented by BMWNA.

Part numbers are set by BMW, not BMWNA, correct?
 
#77 · (Edited)
How can we make you believe without buying a ZHP and an 02+ ZHP, modifying the latter with ZHP control arms and wheels (springs and shocks are the same), and having you drive them?

You keep bringing up the M-sport II rack - why would BMW put this rack in the ZHP and not label it as such in either the ETK or on the part installed on the car? And why are there plenty of non sport/M-sport cars also equipped with 650 racks if the ZHP steering rack is somehow special? At the factory there would have been a lot of confusion if there were two different steering racks that had the exact same labels and housings.

Honestly, I think the difference you're talking about comes down to a romanticized memory of how the ZHP felt, and perhaps a better maintained front end on your former ZHP.

The ZHP package was not "invented" by BMWNA. It was designed by BMW AG as a US exclusive package.
 
#79 · (Edited)
I have no problems accepting the ratios being the same, or the part being the same for that matter. However, my experience, after driving both 02+ cars and ZHPs, is that there is a difference that I cannot associate the feel with the arms or shocks or any other suspension component up front. I have replaced shocks, arms, sway bars, etc. on the BMWs that I have owned, and I think I know exactly what to expect from each one individually. I also replaced the steering box on my wife's older 5er touring, and my expectation before and the feel after the install matched perfectly.

I would love to hear from a non-ZHP owner about the steering feel who had the ZHP arms and shocks installed on their car. Can't believe nobody did these mods...

As I said, the rack can be the same (thus no confusion at the factory), but there have been discussions about additional hydraulic lines and/or retrofit kits when people were having racks installed on their ZHPs. Any comments about those? I'd love to hear more. Maybe there is still some unexplored territory here.
 
#81 ·
You're asking people to validate your beliefs with their opinions. Obviously you will have mixed results. Bottom line is all part numbers are the same (I just triple checked RealOEM)

Believe what you want to. But fact is all non-M 02+ E46s have identical parts for steering.

Sounds like nobody is going to convince you otherwise.
 
#97 · (Edited)
Well I know for sure my zhp was 2.7 turns lock to lock. And there are a couple videos on bimmerfest (probably in the same thread) which show both zhp and non-zhp require 2.7 turns. I'm pretty sure the ZHP does not have a tighter turning circle than other E46s, but I have not measured this.

With regards to the PS pump - that'll effect tightness, not quickness.
 
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#99 ·
Someone's mad :lmao:

You asked two days ago. On that same day I said I would take a picture. Two days later you point the finger and say "YOU DIDN'T POST PICTURES OF UR RACK!!"

If all it took was to do a simple google search to answer your questions, then why couldn't you do that?

From the beginning, I said this information has been discussed for YEARS across various forums. You're a little late to the party.
 
#102 · (Edited)
I did not cut and run Alex. Mango- get my name right bud. I know you know what it is.

At the risk of being cliché, I have things to do in my life outside of bicker with you guys over a topic that has been beaten to death a number of times.

Here's what I see:

- Part numbers (from BMW) are the same. This has been proven multiple times. Not even Sean disagrees with you Mango, but you continue to shove it down his (and everyone elses) throats.
- ZF serial numbers haven't been dissected for a pattern- maybe there is something there. Probably not.
- Apparently there is proof that the lock to lock, etc. is the same based on people measuring it first hand. I have not seen any proof of this.
- ZHP owners, and some who've owned both a ZHP and a ZSP 330, some even with upgraded CAs(!) say they do not feel the same!
- Alex and Mango have no first hand, objective experience to dispute this, so they proceed to rip this large amount of people apart based on part number research. Part numbers are great, but you've got a substantial number of people with more in-person experience than you who disagree. They are so convinced that even with part number research, they will not be convinced. This tends to indicate that there may actually be a difference between the racks.
- Those who swap racks or have/had both a ZHP and a 330 do not concede to Alex or Mango, but tire of the bickering and leave whichever thread got blown up to begin with.

I only posted this because Alex insisted.
 
#103 ·
I did not cut and run Alex.
Here's what I see:
- Part numbers (from BMW) are the same. This has been proven multiple times. Not even Sean disagrees with you Mango, but you continue to shove it down his (and everyone elses) throats.
- ZF serial numbers haven't been dissected for a pattern- maybe there is something there. Probably not.
- Apparently there is proof that the lock to lock, etc. is the same based on people measuring it first hand. I have not seen any proof of this.
- ZHP owners, and some who've owned both a ZHP and a ZSP 330, some even with upgraded CAs say they do not feel the same!
- Part numbers are great, but you've got a substantial number of people with more in-person experience than you who disagree. They are so convinced that even with part number research, they will not be convinced. This tends to indicate that there may actually be a difference between the racks.
Find me some of these "substantial number of people" you say are out there still. There isn't, not even on the forum dedicated to the ZHP are they with you.
The video of the lock-to-lock are posted. If you're going to make a stand and insist something, it's wise to have all the info presented to you. Not ignore the stuff you don't like. :read:

C'mon man... I used to think you were about getting the correct info out. Even rather logical than most when given information. You are going against everything logical presented. this is not me and one other stating the findings of this. this is everyone with maybe one or two hold outs. and i bet they have not even close to the knowledge of BMWs and specifically the E46 to what i know. i don't need to be right, but do my best to present the information gathered for the E46 community. look at all the proof presented. what's your rebuttal to it all....not one bit of proof or fact. your only thing is that some say it "feels" different and we must be wrong.(we even asked you to help your case and do somethings and yet you chose not to or refuse to post the results.) :tsk:

*thanks for the reply. so everyone knows i asked him to reply and thus why it's bumped. i did not however expect the denial stage still
 
#105 ·
Alex, do you think a ZHP and a non-ZHP 330 have the same steering response?

If yes, you are in the minority. Even Terra disagrees with you. If not, then we can talk about the reasons why. If you say it's not the rack, so be it. If it is the CAs that result in this difference, I would like to hear from someone who actually swapped in ZHP CAs to their non-ZHP car.

The reasons you and Terra stated as to why you think ZHP steering is different so far are your best educated guesses. Not absolute proof. As far as I'm concerned, this needs something a little sharper than Occam's razor to cut it :dunno:
 
#107 ·
Sigh... I said I wasn't going to respond until if and when I posted a photo of my part#, but your post is absolutely ridiculous. Are you even listening to what you are saying?

If someone swaps their non-zhp control arms with ZHP arms and feels a "difference" it's not because it's OMG MAGIC ZHP PARTS, it's because you're swapping in an all-metal control arm. Whether it me ZHP or Meyle--same sh!t.

Of course a ZHP and non-ZHP don't have the same steering response. Solid balljoint vs nylon balljoint (outer). Heavier/larger tires/wheels, and if you're comparing non-sport to ZHP, 15mm lower suspension on the ZHP as well as stiffer dampers and swaybars.

Please stop basing your "facts" from this ZHP fantasy land you live in. You do not drive special one-off sports cars--hate to break it to you.

By the way, ImolaZHP just installed Meyle HD control arms in place of his busted 100k ZHP arms. He says the steering is again precise and sharp. :hi:
 
#116 · (Edited)
Sigh... I said I wasn't going to respond until if and when I posted a photo of my part#, but your post is absolutely ridiculous. Are you even listening to what you are saying?

Please stop basing your "facts" from this ZHP fantasy land you live in. You do not drive special one-off sports cars--hate to break it to you.

By the way, ImolaZHP just installed Meyle HD control arms in place of his busted 100k ZHP arms. He says the steering is again precise and sharp. :hi:
Flash, your particular message is an old topic. You are right. The difference you're feeling is all-metal outer balljoint. (not really the fact that it's ZHP) For example, a Meyle HD control arm would give you that same "feeling" because it's also all-metal outer balljoint.

Old topic.

However, this topic has to do with SeanC and ZHP938832028837 claiming their racks, despite being the same part number and proven all over every forum for years, have a "special" feel and "quickness" to them.

They swear it feels so different. They attribute this difference to the steering rack being different although there's other differences as well: bigger sway bars, heavier AND larger tires/wheels, 15mm lower ride height (vs non-sport), smaller 3-spoke steering wheel (vs non-sport).

Redonkulous.
Mr. fact just fvcked up a whole bunch of well known facts. Uh oh.

- ZHP dampers are the same- at least according to BMW part numbers.
- Springs appear to be the same- but may not be because according to some BMW varies springs for pretty much any optional extra. There really is no way to get a grip on the spring situation.
- Sway bars are not bigger

Putting H&R springs on your car doesn't necessarily make it handle better than stock. If anything you should know that from your E36 M3 days. Bilsteins are nice, but a quantifiable increase in handling prowess? I doubt it.

You are so incredibly harsh on people you disagree with that you better get every single fvcking point of every one of your posts right. You blew it.

Redonkulous.
 
#112 ·
Ehh, no. ZHPs are nice, but it's just a "package." The way my car sits now handles better and accelerates faster than a ZHP.

Any ZHP would need to be fully rebuilt anyway (to my standard--the stock suspension would be thrown in the garbage) and so would a sh!t load of other parts. In the end the only thing it would have going for it would be the gloss trim and maybe the 6-speed transmission (which you can get in a 2003 330i non-ZHP anyway)
 
#114 ·
You get the perception of "handling really well" because BMWs are stiffly sprung and stiffly anti-roll barred. The ZHP has even stiffer anti-roll bars. Side to side maneuvering (even with out shocks, and in theory, without struts) wouldn't suffer much as long as you're on a smooth road. Try some high speed maneuvering or braking on a bumpy road surface and you'll notice you need new rubber and shocks/struts. :hi:
 
#115 · (Edited)
ZHP has the same 23.5 front bars and 18mm rear bars as the ZSP. So no, ZHP doesn't have even stiffer bars. In fact, earlier ZSP's (328's) came with 24mm bars, instead of 23.5. ZHP does however have stiffer shocks.

And nobody is claiming the difference in feel is being due to the rack. However, the fact is ZHP turns faster than a ZSP. The claim is there is not enough research to pinpoint the exact reason why.
 
#127 ·
Is there a difference is a "ZF unit" and a "TRW unit"? Trying to get some more useful info out there for people (and myself).
 
#132 · (Edited)
i've hung around here long enough to understand you. personally, i understand and appreciate the maintenance required on these fine cars. i have done quite a bit on my car (click my sig to see how thorough) but to say the entire thing needs to be rebuilt @50k miles is asinine. if you want to replace every bolt and working part with a brand new OEM replacement just for the hell of it, that's cool, and congrats. but that's not at all required for your average enthusiast to get many years of solid reliable performance out of their E46.

also, you cleverly dodged my question of how the list of ZHP upgrades over a standard 330 ZSP has "nothing going for it" as you put.
 
#142 ·
I think it's interesting that people want the quickest rack they can find... but wouldn't that make high-speed steering response annoying and twitchy? Z4 is a short wheelbase car meant for track duty. 3-series (M3 included) are longer wheel base and probably geared for high speed stability (what's the toe-in on the M3?) all I'm saying is careful what you wish for. I know on the S2000s (Ap1 I think) people complained about the steering being too twitchy at speed so they put a more "tame" rack in for later models. Just what I had read
 
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