Looks like I'm going to finally do this mod after thinking about it for 10+ years...thought about the 3.46 diff for 12 years before taking the plunge, car went to the shop yesterday for the install.
Need a good reliable source for a reman Z3 1.9l rack...
Last edited by Gene V; 05-02-2018 at 04:02 PM.
Estoril/Modena '97 M3...sold for the second time.
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You only live once, and I'm running out of time...
Rackdoctor. Just got my E46 ZHP rack from there. It's more expensive than sourcing a junkyard/used unit, but it's flawless and basically like new.
The only bummer is that they don't really give you anything meaningful for a core refund for an M3 rack in return. I ate the core charge because it wasn't worth shipping them my rack for a $30 refund. Anyone need an M3 rack?
Last edited by TostitoBandito; 05-02-2018 at 03:53 PM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Last edited by Gene V; 05-02-2018 at 04:12 PM.
Estoril/Modena '97 M3...sold for the second time.
------------------------------------
You only live once, and I'm running out of time...
All Z3 non-M racks are the same, and are 2.7 turns lock to lock I believe. They're also linear unlike the progressive stock M3 rack.
https://shop.rackdoctor.net/1996-199...95-25460-z.htm
https://shop.rackdoctor.net/1998-200...5995-25460.htm
Either of these work, and are both $360 plus core. Just don't get the Z3 3.2L (M roadster/coupe) rack.
The other option, and what I ended up getting, is the E46 ZHP yellow tag rack ($280 plus core):
https://shop.rackdoctor.net/2002-200...892-712ZHP.htm
This rack is 3.0 turns lock to lock, and is linear unlike the stock M3 rack. More or less in between the Z3 rack and the stock rack, but still a clear and noticeable improvement. It's also desirable for its feel due to its construction (see below for details):
http://forum.e46fanatics.com/showthread.php?t=954523
Last edited by TostitoBandito; 05-02-2018 at 04:45 PM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
I got a rebuilt Z3 non M rack with lifetime warranty for about $235 shipped. I think from Detroit Axle on Amazon.
I also decided on a ZHP rack, but I got mine from a salvage yard (110k miles on the car) I found on https://www.autopartsearch.com/index.wws. If I recall it was $150 or so shipped.
No, it was not rebuilt, but considering my original one had 22x thousand miles and still worked fine, I wasn't too terribly concerned.
I searched for E46 330i racks, and just kept looking until I found one that was from a real ZHP (they usually include the VIN so you can look them up). I found it and did the swap.
You can also search for Z4 M Coupe racks, which are the absolute quickest I'm aware of, but they're super rare.
I know we're perhaps wandering far afield, but you should also look at replacing the steering guibo if you haven't ever done it. Mine had degraded to about the consistency of neoprene. A new one will make a huge difference on it's own, even without your new rack. You could also get the E34 u-joint instead of the E36 guibo. It takes a little more work to fit, will transmit a little more feel / be a little more direct, and it's unlikely to ever need replacing.
But that's a whole new rabbit hole to fall down...
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
Yeah absolutely do replace the steering flex joint when you do it. It's the part that connects the rack to the steering shaft, and you need to disconnect it anyways. It's a couple extra minutes to replace. It has rubber in it so it degrades over time.
As for the Z4M rack, I think I read that this rack needs modification in order to fit and isn't a direct bolt-on.
Last edited by TostitoBandito; 05-02-2018 at 05:56 PM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Only the M3 3.0 has the progressive rack. 3.2 is lineair.
1998 BMW M3 3.2 Cabrio • Alpinweiß III on Schwarz • German spec • 1 of 12
SMG • SRA • PDC • AUC • OBC • GSM • HK • UURS • IHKA • FGR • MFL
IG: https://www.instagram.com/iflok/
All E36 M racks are progressive. Here's some info stolen from another thread:
E46 ZHP rack (yellow tag ending in 712)Z3 non-M racks are all the same.
- LINEAR ratio (same rack travel per input turn across the entire rack length)
- 53.5 mm of linear rack travel per 1 360 degree rotation input.
- 144.5 mm of total rack travel (translates to 2.7 turns L2L)
- installed 13.9:1 ratio
Z3 M racks and '96+ E36 M3 racks are the same.
- PROGRESSIVE ratio (rack is slower on-center, quicker towards L&R rack locks)
- 45.5 mm of linear rack travel on-center per 1 360 degree rotation input.
- 145.6 mm of total rack travel(translates to 3.2 turns L2L)
- installed 15.6:1 mean ratio
- Same p/n rack as E36 non-M, but locks were modified to shorten gear travel from 154.7 to 145.6mm
'95 M3 racks are the slowest and shortest of all US-spec E36 racks, until 200 deg of rotation from on-center.
- PROGRESSIVE ratio
- 39.0 mm of linear rack travel on-center per 1 360 degree rotation input.
- 117mm of total rack travel (translates to 3.0 turns L2L)
- installed 17.6:1 mean ratio
- LINEAR ratio
- 3.0 turns lock to lock
- installed 13:7:1 ratio
Last edited by TostitoBandito; 05-03-2018 at 10:14 AM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
I don't think you want a 1.9 rack, only because SOME of those got a different rack than what is listed, so it's a gamble if you get a 1.9 rack if it's the rack you want or a different one.
What you want is the non-M Z3 6 cylinder rack. Those are all the linear 2.7 LTL racks
However, if you haven't driven a car with this rack installed, I would urge you to do so before installing it. I think a lot of people will do this mod because the forum says its awesome, but then feel a little disappointed because it feels different than they wanted. How the steering feels and responds is really a preference for each driver, how the suspension behaves may be objectively better or worse after certain mods, but steering input is just that - input. So make sure YOU like it before installing it... just my .02 anyways
Going into my TENTH YEAR of providing high quality reproduction BMW fabrics!
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-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
Just do it. Installed a low mileage one from ebay 5 years ago and couldnt be happier. Biggest difference is the turn response from center. There is a big center deadspot on the M racks and the non M Z3 rack eliminates it.
That’s incorrect info. The M3 3.2 and M Z3 have a 45.5mm/turn lineair rack.
Unless the US has this, the Euro certainly does not.
1998 BMW M3 3.2 Cabrio • Alpinweiß III on Schwarz • German spec • 1 of 12
SMG • SRA • PDC • AUC • OBC • GSM • HK • UURS • IHKA • FGR • MFL
IG: https://www.instagram.com/iflok/
Last edited by TostitoBandito; 05-03-2018 at 02:38 PM.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
Last edited by Gene V; 05-03-2018 at 02:52 PM.
Estoril/Modena '97 M3...sold for the second time.
------------------------------------
You only live once, and I'm running out of time...
1998 BMW M3 3.2 Cabrio • Alpinweiß III on Schwarz • German spec • 1 of 12
SMG • SRA • PDC • AUC • OBC • GSM • HK • UURS • IHKA • FGR • MFL
IG: https://www.instagram.com/iflok/
Ok, so then it's a somewhat bigger deal to upgrade the 95 rack then it is for a 96-99. Still, you get a quicker rack, and in the case of the ZHP rack I put in I think a better/sportier feel. I haven't driven a Z3 rack so I can't comment on that.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
I used a '97 1.9L Z3 rack from RockAuto because they provide a spec sheet for their rebuilt ZF racks from most vendors, and the core return of a M3 rack was extremely easy and painless.
Check the rack as soon as it arrives to ensure you received the 2.7LTL rack.
The E34 steering coupler is a welcome upgrade over the OE rubber guibo as well. Been using both for over a year. It would be one of the first mods I would do if I had to do it again. I absolutely despise the M3 rack. No opinion on ZHP.
Good thread. I am at the point where this is gonna be one of my next mods I can no longer ignore the vague on center and overall steering feel.
Z3 vs ZHP rack besides lock to lock is there a difference in feel?? Compared to my Porsche 944 the steering feel in the M3,to put it gently, plain sucks.
Anything else have to be done to fit the E34 joint or is it direct fit?
There's some technical info from rackdoctor on the ZHP rack in this thread:
http://forum.e46fanatics.com/showthread.php?t=954523
He's mostly trying to clarify how it's different/better than other E46 non-ZHP racks which have the same 3.0 lock-to-lock. Just because a rack has the same ratio doesn't mean it will feel the same. The ZHP rack has a larger torsion bar than the other racks, so it has a sportier and more direct feel as opposed to a more "boosted" feel in racks with smaller bars. Judging by the feel, I think there's a similar difference between the ZHP rack and the stock E36 M3 rack as well. If you reach out to rackdoctor they may be willing to go into more detail on the racks you're looking at.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
So... you don't have your own jet?
Yeah, I think first class would be ok.
Vague on-center is probably more your 20-year-old guibo than the rack. I'm not kidding - mine really was the consistency of neoprene.
So no, the E34 joint isn't completely bolt-on. You have to file a notch in the lower part of the upper rod because the E34 is designed so the bolt traps the joint on the upper rod. I just stuck a Dremel bit in the hole until I could get the bolt through. There are other write-ups on it - I'd read about it if you're going to do it.
My guibo was so bad it's hard to say which made more difference, the joint or the ZHP rack.
-Josh: 1998 S54 E36 M3/4/6 with most of the easy stuff and most of the hard stuff. At least twice. 271k miles. 1994 E32 740il with nothing but some MPars. 93k miles.
If you don't want to go the DIY E34 route, just put in a new OEM/BMW flex coupler thing. That's what I did along with my ZHP rack, and it's fine. The new one is way stiffer than the original one with 145K miles and almost 20 years on it.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
I'd really like to understand how these progressive racks work. The mesh between the pinion and rack is pretty tight (it'd have slop if it was not). How can the ratio be varied without changing the pitch/size/count of the teeth on the rack bar and pinion? Also, how could that change without varying the mesh? I just don't understand how this is possible.
For the record, I've had a Z3 rack along with an SLR mini angle kit (roll center and bump steer correction). My steering is probably 30% faster than the Z3 rack on it's own. I absolutely love it. It is so easy to drive, both in daily driving as well as at autocross. I simply do not understand how people would think this is a bad thing. It ROCKS!
From BMW:
"The M3 not only delivers a significant handling margin over the already highly capable 328is – it is also significantly better for 1996!
Variable-ratio, variable-assist power steering
Steering has been specially modified too: In addition to the familiar variable assist, the M3 system has variable ratio to achieve specific response characteristics. The ratio is “slowest” at the center, for best straight-line stability; to improve response in hard cornering and to reduce steering-wheel motion in parking and low-speed maneuvers, it then gets “quicker” as the wheel is turned toward the locks."
See attached docs including AG press release which gives "overall" ratio (i.e., mean or average).
See attached pdf - it describes the F30 variable rack but the technology is the same for the E36 as far as the way they execute the variable rack design.
Last edited by Jim E.; 05-04-2018 at 05:47 PM.
Great info. Those documents seem to indicate that the 96-99 M3 also had a variable/progressive rack, yes? I mean, they tout it as a feature.
1999 M3/2/5 - Titanium Silver - Track/Weekend Toy
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