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

[Itsablurr]

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...

I'm not sure offhand for a re-man source. I'd do a junkyard search and buy there.

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?

I couldn't tell you why you think it feels faster. The numbers and specs are what they are.

[Evil Spoonman]

I couldn't tell you why you think it feels faster. The numbers and specs are what they are.

Fair enough. I'll go back and have another pass on the 95 rack with the data in my head. Perhaps I was mistaken.

[SLR]

Fair enough. I'll go back and have another pass on the 95 rack with the data in my head. Perhaps I was mistaken.

Perhaps the rack was replaced by a previous owner with one of unknown origin?

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

Are you sure the standard E36/96+M3 rack is progressive? On any rack steering system the wheels will turn more per steering revolution the further they are turned just because the steering arm follows an arc and the rack is linear. I am nearly positive the standard E36 rack is linear.


One more thing to add: M3 spindles have a 5mm longer steering arm, so they create a slower steering RATIO, with the same rack vs. non-M spindles

[Pink]

I think we need some more apples to apples comparisons to really nail down the racks. The majority believe the 95 rack is considered faster than the 96+ racks. They also sell for more. $300 vs. <$200.

Can someone explain what the difference is between a linear rack and progressive rack?

There are a lot of technical jargon and theory without practice or solid proof going on here. I'm not saying Itsablurr is wrong or that the numbes are wrong. It's just hard to say, spindle ratio this and center gear that equals a slow rack. Without some actual controlled variable experiments it's hard to think the 95 rack is slower when it sells for more and FEELS faster. Also it seems the consensus on the racks from fastest to slowest are:

1.9 z3 -> 95 m3 -> 96+ e36

It would just be nice to get a dumbed down mythbusters style explanation of these racks to put this whole thing to rest.

[s2rsr]

How about a breakdown of all the different parts used in correlation with the rack to figure out the variables.

How many racks are there for the E36 and what are there specs(facts not speculation)?

How many types of spindles are there and their specs?

Does camber, wheel size and suspension setups effect steering ratio and/or feel?

Are there different types of tie rods and if so do they effect steering geometry?

Are there performance aftermarket racks or racks from other cars that can be used?

What about the whole "speed sensitive power steering" I've heard about on M3's?

Lets get all the facts about racks and get it in a WiKi already instead of having to search the forums for hours.

[SLR]

How many racks are there for the E36 and what are there specs(facts not speculation)?

THREE - the normal rack, the quick rack and the variable rack (95 M3 only)

How many types of spindles are there and their specs?

TWO - M3 and non M3. 95 M3 spindles have less camber built-in, but that doesnt affect steering. The normal E36 spindles have a faster steering ratio than the M3 ones because the steering arm on the M3 spindle is longer (about 5mm)

Does camber, wheel size and suspension setups effect steering ratio and/or feel?

No it doesn't affect ratio. Of course all of those will affect feel. Size, width, camber, caster, scrub-radius and roll center will all have an effect.

Are there different types of tie rods and if so do they effect steering geometry?

NO and NO

Are there performance aftermarket racks or racks from other cars that can be used?

Other E36 racks and possibly E46 racks?? Of course there are aftermarket racks for these cars. I'm sure from racing and rally builders in Europe especially.

What about the whole "speed sensitive power steering" I've heard about on M3's?

No such thing on E36's.

[Itsablurr]

Are you sure the standard E36/96+M3 rack is progressive? On any rack steering system the wheels will turn more per steering revolution the further they are turned just because the steering arm follows an arc and the rack is linear. I am nearly positive the standard E36 rack is linear.

Yep, I am positive. All US E36 3-series racks are progressively geared. Well documented by many individuals and rebuilders.

I think we need some more apples to apples comparisons to really nail down the racks. The majority believe the 95 rack is considered faster than the 96+ racks. They also sell for more. $300 vs. <$200.

The apples-to-apples comparison is the mm/rev spec for any interchangeable rack. I wouldn't say the majority consider the '95 rack as faster, as it isn't. Perhaps a few confuse it to be faster based off of how misinformation spreads in an area where the hard numbers are somewhat difficult to come by or filter out from the noise.

Can someone explain what the difference is between a linear rack and progressive rack?

A linear rack moves at a constant linear rate per 360 deg of revolution of the pinion gear. A progressive rack has the gearing cut such that the linear displacement per 360 deg of pinion rotation is slower on-center.... it has the effect of eliminating straight line twitchiness, while sacrificing initial turn-in liveliness.

[adamnur]

Great info in this thread, thanks.

[BadBoostedBmwM3]

Wow, I just learned a whole lot about 1995 m3.

[Moron95M3]

so then...

what racks are in Z3 M's?

(seeing how much info is in this thread...might as well try to add more )

and I swear my old 95 rack seems quicker at center than my nonM E36 (which is equivilant to a 96+ M correct?) Maybe it's due to the body roll/tires...

[MotionMotorsport]

Z3M racks are the same as E36M racks.

[Moron95M3]

Z3M racks are the same as E36M racks.

as in 96+ which also is nonM E36's yes?

thanks - just trying to get even more info in this thread

[calypsoSA]

Sorry to go somewhat off topic. But does anyone have the ZF part number for a Z3 (non M) rack? The local agents here cant find it via the BMW part number.

TIA

[SLR]

Basically there is a simple rule here:

ALL E36 racks (including Z3 and ti) are the same with only TWO exceptions.

1-1995 M3 is slower (less mm per pinion revolution)

2-Any Z3 besides M models, is faster (more mm per revolution)

[87Cabrio89is]

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.

Old thread, but worth posting to keep the information in one place. I'm 99.99% confident that the number in the right corner is the build date. I pulled a rack from a 1995 325iA-4 (automatic 4 door) at a Pull-n-Save this weekend ($41 +$3 core charge). The car was built in March of 1995 and the ZF rack has an 0395 code where the OP's was 0292. Pics added for proof!

[dwonda]

I can confirm that not all Z3 racks are 2.7 turns ltl, mine is about 3.2. I also tried a ZHP/330/712 rack today, that was around 3.2, it's a crazy world out there.

[bluptgm3]

K


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[BacDoc]

Raised from the dead again!

'95M here...upgrade to either Z3 (non-M) or any other E36 rack? If I were to buy just the gear/housing would all my '95 rack parts, tie rods, ball joints swap over?

And is there simply a part number or two to look for in the best rack?

[pbonsalb]

It’s really Z3 non-M or E46 purple tag. The former bolts right in; the latter requires minor mods but you are more likely to find a cheap used one in good shape since it is newer. Rebuilt ones run in the $235 and up range. I bought my Z3 rack from Detroit Axle for $235 with no core charge.

[TostitoBandito]

It's E46 yellow tag isn't it? The ZHP rack (712 part #). It's not quite as short as the Z3 rack but still linear and significantly shorter than the stock M3 rack. It bolts right in and takes E36 outers.

http://www.zhpmafia.com/forums/showt...are*-different

[BacDoc]

Anyone know if the inner tie rods I have now match up to the non-M Z?

[Moron95M3]

I used OEM tie rods for my nonM Z rack. There is a catch on the rack not having the locking tabs IIRC...I think I used the bend over lock washer.

It's been years though, hard to remember.

[bluptgm3]

Moving from from standard 4-spoke to slightly smaller diameter Z3/‘99M3 3-Spoke quickens up even the standard E36 rack feel


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[Ex36]

Moving from from standard 4-spoke to slightly smaller diameter Z3/‘99M3 3-Spoke quickens up even the standard E36 rack

Huh?! How does physics work where you live? A smaller diameter wheel will reduce your leverage, making it a little harder to turn the wheel. But it most certainly doesn't change the steering ratio, which is a function of the rack internals.

[bluptgm3]

Huh?! How does physics work where you live? A smaller diameter wheel will reduce your leverage, making it a little harder to turn the wheel. But it most certainly doesn't change the steering ratio, which is a function of the rack internals.

Right. 180 degrees of wheel rotation is still 180 degrees. With a 3-and-9 hand position, the actual distances traveled (smaller radius) is shorter and arms can cross a bit further without having to ‘shuffle’ steer…and ‘shuffle’ steer happens a bit quicker also due to smaller diameter wheel.

Overall ratio does change, however rack ratio does not change. The net affect is removing the school bus wheel feel. The slight addition to steering force required isn’t really noticed especially once the wheels are rolling.

There is a catch on the rack not having the locking tabs IIRC...I think I used the bend over lock washer.

What is the ‘catch’? Does the non-‘M’ rack not ‘feature’ the end notch to accept the inner tie rod locking plate?

The non-‘M’ installation uses a flat sheet inner tie rod locking plate and ‘M’ (at least M3) uses flat sheet with a 1/8th inch horse-shoe ‘stop’ that limits rack sector gear travel.


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