Need help to determine what steering box I have!

[Kannackas]

Hi,

I bought a rebuilt steering box from a company a while back. They said they were sure that the box was the special edition 850CSi one that had the quicker steering ratio, but when I ran the ZF part number on the steering box it seems like its from a regular 850/750i.

I thought someone on here would probably know and I want to see if I can get some info before I call the company and demand a refund because they seemed very unwilling to admit that its not the correct box when I first sent them an email about it.

The number on the box is: ZF 8054501241

[rjjablo]

This is my Steering Box out of a 1991 BMW 850, No idea what a CSI one looks like

[Kannackas]

They look the same but the part number should be different since the ratios are different.

[shogun]

workshop manual shows for all E31 a ratio of 13.5, E32 14.5, see page 32-16 https://www.bmwtechinfo.com/repair/main/941en/index.htm

[Kannackas]

So it's a lie that someone made up about how the CSi had quicker ratio than the others?

[mbarrett635]

Well, I don't know who told you that, or what you were actually told -- but the CSi does in fact have a different steering box than the other 8 series cars. However, the ratio isn't what's different. Instead, the CSi's power steering assist is road speed sensitive, rather than engine speed sensitive. I assume the steering box is a different part; I'm sure the controller is also different.

[Timm]

There are numerous steering boxes available for the E31 - and there are at least three Servotronic (Hydro Steering) modules to go with them. All Servotronic systems are road-speed sensitive but I would guess there is a difference in speed-to-assistance mapping for the CSi versions. The CSi versions are also different depending on country variant and further complicated by the availability of AHK in the Euro versions - goodness knows what all the differences are!

http://www.realoem.com/bmw/enUS/show...diagId=32_0287

http://www.realoem.com/bmw/enUS/show...diagId=32_0674

http://www.realoem.com/bmw/enUS/show...diagId=32_0287

http://www.realoem.com/bmw/enUS/show...diagId=32_0294