E36 racks: let's settle it once and for all.

[JGood]

How exactly do progressive racks work? I can't wrap my head around it.

The rack gears are straighter and skinnier in the center, more slanted and fatter off center, so for each revolution of the pinion, the amount of rack movement varies.

I want to add some data to this thread. I spent some time with an e36 325 (silver 227 11/92 tag) and e36 95 m3 (green 237 6/95 tag) side by side. The e36 325 rack is linear, the 95 M3 rack is progressive. The 95 M3 rack is *slightly* slower on center, but noticeably quicker after about a 1/2 turn of the wheel in either direction.

I measured my e36 rack as 44mm/rev the whole way through. The 95 M3 rack was about 42mm/rev for the first half-rev, but after that jumped up to 50mm.

Both racks had 160mm of travel. The M3 rack does it with 3.2 turns, the e36 325i rack does it with 3.5. Meaning the overall ratio of the 95 M3 rack is quicker then the 325i rack, although it is slightly slower on-center.

I plan on getting some more precise on-center measurements, maybe at 1/8-rev increments.

Proof of linear vs progressive:


95 M3:





e36 325i:

[AndrewBird]

How exactly do progressive racks work? I can't wrap my head around it.

[jeffnhiscars]

what are people doing with the rack spacers? top or bottom? anyone noticed bump steer?

mine are on top of my z3 rack and i notice some bumpsteer, yet i still had what i would call bump steer on the stock rack (may have been just worn as hell) and the z3 rack didnt make it worse. im thinking of splitting the difference and putting 1/2 thickness spacer at both top and bottom that way the rack is centered

I've installed 4 e36 racks on a range of bodies & suspensions (some e30 tie rods some e36, std CABs & M3 offsets, Bilstein sports VS Touring, sport springs & OE) and have never had an issue with bump steer. Spacers always on top.

[digger]

what are people doing with the rack spacers? top or bottom? anyone noticed bump steer?

mine are on top of my z3 rack and i notice some bumpsteer, yet i still had what i would call bump steer on the stock rack (may have been just worn as hell) and the z3 rack didnt make it worse. im thinking of splitting the difference and putting 1/2 thickness spacer at both top and bottom that way the rack is centered

[metris228]

Does this also apply to right hand drive racks?
Does anyone have a reliable source on rhd rack ratios?

I've searched and the contradictions seem to be even worse than lhd... sigh

Thanks in advance! :)

Okay, I did not read the entire thread, but in fact I barely read any of it, but all I'm going to say is what wh33lhop's cliffs are correct. Here are some measurements that my friend who races an M coupe took from some race car drivers that took the measurements themeselves:

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

And btw, regular z3 rack > z3M rack = regular e36 rack

So the regular z3 rack would be the best. Sucks for me cuz I JUST had my '95 M3 rack installed after I discovered this info. FML!!!!!

/thread

[Northern]

I feel like we should have a comparison in this thread between these older options and things like Z4 (Not sure if progressive or linear) I have a very basic, unconfirmed and incomplete list:

Z4M coupe: 12.8:1 / 2.5 L2L
Z4M Roadster: 13.7:1 (same ratio and housing as E46 ZHP/some 330's, just with the long Z4 spline)
Non-M Z4 3.0L non-assisted: 14.5:1 / 3.0 L2L / Travel 144.6mm / 48.2mm/revolution
Non-M Z4 non-3.0L non-assisted: ?maybe the same as the 3.0 but listed separately?

(Z4M source)
(Z4 3.0 non-assisted source)

I believe the splines are ~1" longer than e36 racks, so something shorter has to be made from the e30 linkage and/or Z4 linkage.

For ref:
Z3 nonM: 13.9:1 / 2.7 L2L / 53.5mm/revolution
E36: 15.6:1(mean) / 3.2 L2L / 45.5 mm/revolution
(source)


Point out anything additional/wrong and I'll change it.

[JGood]

I want to add some data to this thread. I spent some time with an e36 325 (silver 227 11/92 tag) and e36 95 m3 (green 237 6/95 tag) side by side. The e36 325 rack is linear, the 95 M3 rack is progressive. The 95 M3 rack is *slightly* slower on center, but noticeably quicker after about a 1/2 turn of the wheel in either direction.

I measured my e36 rack as 44mm/rev the whole way through. The 95 M3 rack was about 42mm/rev for the first half-rev, but after that jumped up to 50mm.

Both racks had 160mm of travel. The M3 rack does it with 3.2 turns, the e36 325i rack does it with 3.5. Meaning the overall ratio of the 95 M3 rack is quicker then the 325i rack, although it is slightly slower on-center.

I plan on getting some more precise on-center measurements, maybe at 1/8-rev increments.

Proof of linear vs progressive:


95 M3:





e36 325i:

[Groo]

Thanks tring to understand what the steeringwheel size has to do wth LTL.
in the olympics sprinters use block to run the 100m so each sprinter being a different size wheel,
380,360,320. not sure if the blocks are adjustable, they run with power, control and stability the first stride left back right front granting power or stability ( depends on the runner ) the second power or control... so from center the first turn in on a 2.7 is quicker second being slower?
what are the stock mm for the z3 mz3 95m and e30,
whould just chainging the wheel before rack provide better steering control and stability?
with the 95m rack or 96 3.2 for that matter have equill response to the z3 with a small steeringwheel?
thanks.

[robrez]

All non-M z3 have the same 2.7 LtL rack. All MZ3 have the 96+ e36 m3 3.2 LtL rack. If you find a z3 with a different rack, it has been replaced for some reason.

This man is correct

Authentic 2.7 lock racks have part numbers that end in 031. I don't refer to them as any specific z3 make because some z3s came with 3.2 lock and some came 2.7. In my experience, I have had more 2.7 lock racks found in the 6-cylinder z3s (besides m) than in the z3 1.9 4-cylinder. Mine came off of a 1998 z3 2.8 ending in 031 that I picked for $80 at a yard two years ago.

The only way to know for sure is to verify the part number on the rack ends in 031

If it's original, yes, 031 would be the last 3 digits. However, 031 is NLA. 32 13 1 092 611 is new. Remanufactured is 32 13 1 095 575, which is the part number on realoem for the full line of non-M Z3s -- all aforementioned are 2.7 lock to lock. I got this info straight from Ron Styger a while back.

[JinormusJ]

E36 racks: let's settle it once and for all.

Authentic 2.7 lock racks have part numbers that end in 031. I don't refer to them as any specific z3 make because some z3s came with 3.2 lock and some came 2.7. In my experience, I have had more 2.7 lock racks found in the 6-cylinder z3s (besides m) than in the z3 1.9 4-cylinder. Mine came off of a 1998 z3 2.8 ending in 031 that I picked for $80 at a yard two years ago.

The only way to know for sure is to verify the part number on the rack ends in 031

[Bimmerman325i]

All non-M z3 have the same 2.7 LtL rack. All MZ3 have the 96+ e36 m3 3.2 LtL rack. If you find a z3 with a different rack, it has been replaced for some reason.

I got mine from a local yard for ~$150 shipped a year ago. Look on car-part.com for yards nearby. The racks have gone up but some yards haven't gotten the memo.

[glucklich21]

Ya there has definitely got to be something missing here. My 2.7 LTL rack came from a 2001 z3 convertible off of a separate forum.

As did mine. 2001 Z3 with a 2.8L M52.

[the imitator]

Ya there has definitely got to be something missing here. My 2.7 LTL rack came from a 2001 z3 convertible off of a separate forum.

[itskingsteelo]

a lot of help. im gonna go out and buy a z3 rack soon.

[Northern]

Bump...can anyone confirm my suspicions?

I have heard this as well, but I can't remember where, and I have no additional info.