Are m and non m steering racks the same after 1995?

[alpinem3///]

I have searched all over the place are m and non m steering racks the same ratio after 1995? I know 95 is different. Real OEM list the same pn after 1995 for an m3 as well as a 325 or 328 steering rack. Anyone know for sure what the deal is?

[Itsablurr]

Non-M E36 racks and 96+ M3 racks are the same... progressive racks with 15.4:1 ratio @ lock on a 15.6:1 mean over the length of the rack. 45.5 mm/rev on-center. Same part #s.

However, the M3 racks had a restricted rack lock over the regular E36 for .2 less turns lock-to-lock... altering turning radius to deal with altered control arm geometry with increased caster.

95 M3 racks are different, being 15.4:1 ratio @ lock on a 17.6:1 mean over the length of the rack. 39.0 mm/rev on-center. These racks had a 19.8:1 ratio on center, progressing to the 15.4:1 at 200 degrees of rotation.

95 M racks are the slowest progressive power racks built by BMW. To be avoided.

[alpinem3///]

Thank you so much. I have been searching for ever trying to figure this out. When I enter the part number of my new rack in to realoem.com it does not find anything. I am fairly certain its a non m 92-99 rack. I hope I dont miss my old 95' s shorter ratio. The new racks part number is 7852955227. But in the corner of the manufacture tag it says 0292 on the right side, I am assuming that this is the original build date before it was refurbished do you happen to know? Thanks again for the advice and help.

[biglovin]

confused??? soooo does the 95 rack take more turns from extreme left to extreme right than 96+?

[RRSperry]

Interesting... Every time I've driven a 96+ M3 I've felt the rack was slower than my 95.. In fact I always seen that the only rack faster than the 95 was the Z3...

As always, I could be wrong.

[Itsablurr]

confused??? soooo does the 95 rack take more turns from extreme left to extreme right than 96+?

No, the 95 M3 actually takes less turn lock to lock because the rack gear itself is shorter. 117mm versus 145.6mm on the 96+ M3. That is a big part of the reason why so many people get confused and think the 95 M3 rack is 'better'... because it demonstrates 3.0 turns from lock to lock, versus 3.2.

Thank you so much. I have been searching for ever trying to figure this out. When I enter the part number of my new rack in to realoem.com it does not find anything. I am fairly certain its a non m 92-99 rack. I hope I dont miss my old 95' s shorter ratio. The new racks part number is 7852955227. But in the corner of the manufacture tag it says 0292 on the right side, I am assuming that this is the original build date before it was refurbished do you happen to know? Thanks again for the advice and help.

That part number is a ZF part number, not a BMW part number. ZF is the supplier of racks to BMW. As far as the other number, I'm not sure... most likely a date code/manufacturing lot/shift code.

Interesting... Every time I've driven a 96+ M3 I've felt the rack was slower than my 95.. In fact I always seen that the only rack faster than the 95 was the Z3...

As always, I could be wrong.

There is a lot of tribal information floating around about the various racks. Some of it is incorrect, some partially correct, and some is correct. The 95 M3 rack has both the slowest on-center mm/rev ratio and has the most limited lock-to lock travel of all US-spec E36/Z3/Z4/E46 racks.

1995 M3:
mm/rev on center: 39.0mm
rack type: progressive
on-center ratio: 19.8:1
ratio @ lock: 15.4:1
mean ratio: 17.6:1
rack length: 117mm
turns lock to lock: 3.0

1996+ M3
mm/rev on center: 45.5mm
rack type: progressive
on-center ratio: -
ratio @ lock: 15.4:1
mean ratio: 15.6:1
rack length: 145.6mm
turns lock to lock: 3.2

Rack Ratio is a calculation of how many degrees the front wheels turn per 1 360 degree turn of the steering wheel. Steering Rack Ratios are application-specific, and dependent upon the geometry of the spindle they are attached to. Since the interface between the spindle pivot point and tie rod attachment point create the geometry of a lever, two identical racks installed into two differing chassis may result in differening ratios, as the lever geometry resulting from the spindles in each chassis may be different. The most accurate way to compare rack performance is the on-center mm/rev spec. Simply put, this is the linear translation in millimeters per 1 360 degree rotation of the pinion gear from center (defines initial rack quickness). Overall rack gear length determines the lock to lock range and comparitive turning radius potential.

[biglovin]

so in diffeernt driving situation (bendies, drifting, track, ect) where would these aspects be beneficial or opposite of beneficial?

[Itsablurr]

Well, the slower on-center a rack is, the less darty the car feels when traveling straight at high speed. You do reach a point of diminishing returns, though. I can see the benefit for grand touring applications. The faster on-center a rack is, the more lively and responsive the car becomes to given steering inputs. This is a bonus on the track or auto-x.

IMO, the progressive racks were all part of the scheme of making BMW performance cars slip a little bit further down the slope of becoming more appealing to the masses, catering less to the enthusiast.... heavier, bigger, plusher, more isolated.

I feel the 96+ M rack is best suited for a tourer, and should have been equipped with a faster, linear rack from the factory.

[evandro]

Itsablurr, you know the business! Any chance you could post the specs of the non-M Z3 rack, considered to be the faster we can bolt on an E36 M3, and your opinion about it (if you've already driven and M3 with it of course)? Thanks in advance.

[Itsablurr]

Off the top of my head, that rack is linear and is spec'd at 53.5 mm/rev, 2.7 turns lock to lock, 13.9:1 ratio, and 144.5mm rack gear length.

That rack feels great on the M3, and is an example of what should have come on it and the MZ3 in the first place.

[336motorsports]

Damn good info!

[alpinem3///]

What does this mean:

However, the M3 racks had a restricted rack lock over the regular E36 for .2 less turns lock-to-loc. I had never heard of this prior.

Can I alter my steering rack if its a non m to be the same as an m by getting rid of the rack lock somehow.

I am switching out a 95 m3 steering rack for a non m steering rack. So I basically going from 3 to 3.4 turns at full lock. On a street driven car will it make a noticeable difference? Thanks for the help.

[Itsablurr]

What does this mean:

"However, the M3 racks had a restricted rack lock over the regular E36 for .2 less turns lock-to-lock." I had never heard of this prior.

It means that the racks are the same part number, but the M3 racks have had their overall travel range limited by about 10mm. I believe this is to help compensate for altered caster and the resulting clearances of the tire lock to lock. This results in an E36 rack having 3.4 turns lock to lock, and the limited M3 application having 3.2 turns.

About not having heard about that, there's not a lot of consolidated info regarding the masses of steering racks out there... and thats not even getting into the ones from other models swappable between chassis.

There's a 1-stop database that is nearly done that shows all of the cross-platform specs and swappability details for steering racks.

Can I alter my steering rack if its a non m to be the same as an m by getting rid of the rack lock somehow.

I don't know the answer to that at this point in time.

I am switching out a 95 m3 steering rack for a non m steering rack. So I basically going from 3 to 3.4 turns at full lock. On a street driven car will it make a noticeable difference? Thanks for the help.

On a street driven car, your initial turn-in ratio will be quicker and thus feel more responsive. As you approach and go past a half turn of the steering wheel, the steering responsiveness should feel about the same as the 95 rack, and the final difference is that you will be able to turn the wheel further for a reduced turning radius of the car.

[alpinem3///]

Thanks for the help. I am going to install the non m rack and see how it feels compared to old leaking 95 m3 rack.

[Rakshas]

Itsablurr you're posting some great info. Would you happen to know the specs on the E46 330i rack? I've heard it's the quickest rack of all(even more so than the 1.9l Z3 rack).

[rebs]

Itsablurr you're posting some great info. Would you happen to know the specs on the E36 330i rack? I've heard it's the quickest rack of all(even more so than the 1.9l Z3 rack).

Dont you mean e46? iirc...

[evandro]

Off the top of my head, that rack is linear and is spec'd at 53.5 mm/rev, 2.7 turns lock to lock, 13.9:1 ratio, and 144.5mm rack gear length.

That rack feels great on the M3, and is an example of what should have come on it and the MZ3 in the first place.

Fantastic, mate, great info!
Cheers!

[Itsablurr]

Itsablurr you're posting some great info. Would you happen to know the specs on the E36 330i rack? I've heard it's the quickest rack of all(even more so than the 1.9l Z3 rack).

I have some specs on it.... all except the critical on-center mm/rev spec. Waiting to hear back from ZF/BMW after the holidays.

I assume the rack you're talking about is the E46 330 ZHP and 330i post-9/2001. It has a 13.7:1 overall ratio, 3.0 turns L2L. Unfortunately, that doesn't tell the whole story in terms of how it compares to other racks.

[biglovin]

Trivial question: do the z3 racks directly bolt up to an M3

[Badgtho is back]

Itsablurr you're posting some great info. Would you happen to know the specs on the E36 330i rack? I've heard it's the quickest rack of all(even more so than the 1.9l Z3 rack).

can you post the E36 370tii rack along with the racks for other fictional cars?

ITSABLURR .....seriously good info in this thread... really, well done.

Trivial question: do the z3 racks directly bolt up to an M3

yes.. the z3 rack is a common upgrade

[Rakshas]

Dont you mean e46? iirc...

I have some specs on it.... all except the critical on-center mm/rev spec. Waiting to hear back from ZF/BMW after the holidays.

I assume the rack you're talking about is the E46 330 ZHP and 330i post-9/2001. It has a 13.7:1 overall ratio, 3.0 turns L2L. Unfortunately, that doesn't tell the whole story in terms of how it compares to other racks.

Thanks, sorry for the typo I did indeed mean the E46 330i rack.

can you post the E36 370tii rack along with the racks for other fictional cars?

ITSABLURR .....seriously good info in this thread... really, well done.




yes.. the z3 rack is a common upgrade

Well aren't you just a bag of sunshine?

[Balthazarr]

Well aren't you just a bag of sunshine?

lol

Considering that, in my 95, I can U-turn without going L-L from the Left turn lane into the second lane in the opposing direction where most cars need the entire 1st lane or to even stop to avoid the curb , I'd say that's pretty quick.

[NicoyAKinG]

awwe, so the 95' M3's have the shittiest racks?

[fun2drive]

Itsablurr :
Since you have knowledge in this area can you suggest a few places that you know that do a good job on a re-manufactured rack?
Thanks and I am sure many of us want to know...

[Evil Spoonman]

Personal experience has led me to observe that the 95 rack feels faster… you say this is not so? Why does it feel faster then?