E30 M3 steering rack vs non-M rack (not discussion about E36 or E46 racks)

[noid]

The E36/E46 (including E36 Z3) rack swap conversation has been beat to death, so lets refrain from discussing those here.

Any one run an e30 M3 steering rack in their Non-M?

The specs as I have read in other threads (not sure where raw measurements originated):

Non M = 36.5 mm/rev X 4 rev L2L = 146 mm total travel
M3 = 38 mm/rev X 3.5 rev L2L = 133 mm total travel

Questions:

1. Did you notice a reduction of overall steering travel (Ie. U-turns)?
2. Was the increase in mm/rev noticeable? Significantly?
3. I have read from one post (literally 1) that there are dampeners in the M3 rack that stabilise the car at higher speeds. Do you feel this is true?
4. Did you have to do any mods what-so-ever to make it fit?
5. Would you recommend the swap to others (if it was exclusively a choice between E30 non-m and E30 M3 rack)?

[flyboyx]

it does seem incrementally quicker. not worth the extra cost though. just get an e36 rack.

i sold the one i had. meh

[brads2002]

Having both cars I have never really noticed a difference between driving the 2. That being said I guess I have never zeroed into thinking about it when driving.

I now have a e36 rack in the 318 and always notice the improvement when driving.

[IronJoe]

I never noticed a significant difference in steering ratio between my M3 and the few non-M e30's I've owned.

[Balleristic31]

I've been using an E30 m3 rack for a few years now on my 318is (with no power steering if that matters). Noticeable but not dramatic improvement in steering response.

No modifications needed to install just bolted right up to my airbag steering column/ knuckle setup. Used my stock e30 tie rods.

Overall it is an upgrade but with the other quicker options out there I wouldn't really do it again unless I got the m3 rack for a very good price.

[MC Hammered]

I have the progressive e36 M3 rack in the wagon and the linear e46 zhp rack (closest to the linear non M3 1.9 rack) in the vert.

The zhp rack does turn quicker, but the biggest difference is the progressive rack has is the dead spot in the middle before you start turning.

There is no dead spot in the linear rack, so when you want to turn it does so immediately.

I prefer the feel of the e46 rack so much that I'm itching to swap out the e36 M3 rack as soon as my mod fund permits.

[noid]

Just completed the swap, here is my feedback.

My observations:

Not all E30 M3 racks have green identification plates; mine had a silver plate, note the correct E30 M3 part number (same number as on green plate). Only difference is production date on silver plate is 07/87




Secondly, its hard to tell from the pictures, but the M3 rack seems to be a lot more heavy duty, particularly the pinion housing:


One HUGE difference between the two is the way the racks are assembled, the E30 non-m uses a cast alum housing with pre-cast mounts. When a rebuilder rebuilds a non-M rack they cant mess up the mounting. This is however very different for the M3 rack because the rack housing rotates relative to the pinion housing, and must be reassembled PERFECTLY, or the rack will not mount as the holes will not line up.

There is a big lock nut right where the pinion assembly and the rack assembly meet that can be loosened and mounting brackets adjusted (by turning the rack housing relative to pinion housing). You will need a punch to loosen and retighten this nut (if re-builder got it 1-2mm off).

Another potential hurdle is the return power steering line that connects to the rack; in my case the line had been replaced at some point and was not long enough to reconnect to the M3 rack, this was because the M3 has 2 casting nubs that are very particular about how the hose is routed, wherein the non-m rack does not have these nubs.

I suspect if the line were original this wouldnt have been an issue, and its something new 16mm ID line fixed easily.

My feeling about the M3 rack vs non-m:
I noticed a slight increase in steering effort, which is nice and gives for a better feel.

The rack is marginally but noticeably quicker. At the points in a turn where you would normally cross over hands to continue turning the wheel. The rack feels more refined, wherein I feel I am getting to the edge of needing to cross over but not quite there.

Overall pleased with the swap, and would do it again.