The standard way ZF quote on-centre (straight ahead) ratio is in mm/rev, which is the travel in mm of the rack bar per revolution of the hand wheel. The higher the mm/rev the faster the rack.

M3 3.0 - 39 mm/rev - the slowest available rack. This is a variable ratio but it is slower than standard until 200 deg hand wheel angle

M3 3.2 and standard E36 - 45.5 mm/rev - the M3 3.2 rack has restricted lock.

Z3 rack - 53.5 mm/rev - by far the quickest rack you can fit.

E46 compact rack - 50 mm/rev - apparently this also fits the E36

Because the M3 3.0 has a variable rack it has the smallest lock to lock at 3.0 turns but don’t be fooled it is the slowest by a country mile. A worthwhile upgrade for any 3.0 M3 (or a track based E30 with one of these fitted) would be to fit a standard E36 rack (or even a Z3 rack) which is what I did a year ago with a noticeable improvement.

Pooky,

As always, good info......

I've run a stock e36 rack in an M3 as well and I'm not sure, (in my experience) I'd bother changing the rack in the 3.0l M3 e36 to a standard e36 one........ but I suppose you can't argue with the facts if you intend to change the rack in an e30, it make sense to go for the quicker rack.

The idea of the variable rack in the M3 was too make it speed sensitive.....not too everyones liking, but it cetainly worked, i.e slower at low speeds.

While you are talking to your man at ZF ask about the e36 320 rack, as fitted to the later 320i M52 variant, I seem to remember an urban myth surrounding this one....(it has a different part number to the rest of the range 316 - 328).....

215DMX wrote: Don't forget that the length of the steering arms will also have an effect as to the overall ratio. A Z3 rack on a e36 'should' have a different ratio as opposed to when it is mounted on a Z3 for example because of different fittment (though it would be quicker than the original e36 rack) Excellent info though. I've been looking for a LHD Z3 rack for a while now...

Of course the overall steering ratio between hand wheel and road wheel is a combination of steering arm length, column phasing and steering rack ratio so this is just a comparison of rack ratios that could be fitted to the E36.

The Z3 rack bolts straight on just needs a small bracket to mount the pipes - approx 50mm flat plate. Have a look on e36coupe as M3 compact supplied a picture.

Great info pooky...

YEESSS great info Pooky. Thanks.

Same as M3PSM, for me this is THE one thing to change on the M3 Evo. Even more so when I drive it again after having driven my brother's Evo VI...

Hi Pooky,

Do you have the part number of the Z3 rack. Or at least what type of Z3 exactly?
As I'm just having a look at BMW references, and that of the Z3M is the same as the M3 Evo, so can't find out...

Thanks

denishogan wrote: How many turns lock to lock with the Z3 rack? And is there any specific Z3 rack to look for? i.e. one out of a 4 pot or a 6 pot Z3 Cheers, Denis

Can't remember the turns lock to lock but there is a very tight corkscrew type hill near me and I have to turn the wheel in my M3 much further going around the bends. I had a 2.2 Z3. Also the steering wheel in the M3 is ~380mm compared to the ~370mm in the Zed and my 5 series, which feel noticeably smaller.