rack and pinion 101

[Philo]

Hey Bill.., after reading up on your first post on converting over to a R&P.., I decided to take the plunge ! I've gone through 3 reman ZF M5 steering boxes and have had nothing but problems. So the decision was easy. Spend yet another $800 - $1,000 on rebuilt ZF box.., or convert to a rack. No brainer. I'm hoping to get the project done for around $400.

My choice for the rack is the 924 - 944 rack. The reason is that it takes 110 psi from the pump.., and happens to be the same as the stock e28 pump. However.., I got lucky, I found a guy in Los Angels that had a bunch of 944s that he was parting and was able to get the rack, pump, mounts, and dual universal link, all for $100. Not bad.., not bad at all.

This evening I spent a few hours lining everything up so to weld on some mount tabs. Will post some more pics as I get further along. Your post has been of great help and will definitely same me time in the long run knowing in advance how to tackle certain conversion issues. Also a big thanks to Spongbob for great shots of his project.

[Philo]

Guys.., the 944 rack is not an option for the e28 chassis !

I emailed some photos of my conversion project over to Joe Cain, the guy who built the custom V8 e12, and he caught the problem right off the bat. The 944 rack is a front steer setup and the e28 is a rear steer setup. So if I had mounted the 944 rack and installed it on the car.., turning the steering wheel to the right would make a left turn. I'm still laughing at this mistake. But the bigger issue is why hasn't anyone mentioned front/rear steer racks in this thread ! Not that I'm blaming anyone....

All in good fun.., so now I'm going to source an e39 rack and go the road of SpngeBob...

[bm0p700f]

Mount it upside down and that will sort that problem.

[Philo]

You got pictures of how that works

[misha]

this is really great info guys. Sounds like a very cool modification to do to our cars.

[bm0p700f]

No pictures but it would work if it could be mounted. The angle at which the steering column enter the box when its upside down might be a problem however depending on it design. I know one chap over here who planning to use a e36 steering rack and this is his solution to the same problem.

[Shawn D.]

Mount it upside down and that will sort that problem.

That would only work if you took a LHD front-steer box and put it on a RHD rear-steer car (or RHD front-steer box on a LHD rear-steer car).

[Philo]

Oh.., I totally though you were joking !

There is no way to flip the rack around. The rack and pinion are designed to work one way.., and one way only. And is secured by a cast aluminum piece mating the tow together. Absolutely no way to re-engineer the rack without cutting everything apart.

Thanks for the help.

P.
_____________

[SpongeBob]

Guys - I completely screwed up.

The e39 rack is a front steer rack, not a rear steer and will NOT work in an e28. I just walked out the garage and figured it out - I am so bummed. I thought I had done my homework, but w/o an e39 to look at - my only source of info was the ETK - it is not real clear how it mounts. I apologize.

This was pointed out to me by Phillo.

I want to apologize to the entire Mye28 Crew - I totally screwed up.

SBSP

[Bill in MN]

Spongebob

There's an easy fix. Flip it over and make a RHD out of it

[SpongeBob]

Flip the car over? Man - it is really heavy.

But I am confused, if I do that - then it will only work in the southern hemisphere? I've always wanted to go to New Zealand and drive.

I am a certified "pop tart".

On a related note, I am looking at last generation VW GTI/Jetta GTX's - I think that will work and it has the same steering ratio as the BMW rack. Will keep you posted.

SBSP

[bm0p700f]

Ah thanks shawn thats why it works over here.

[Philo]

Anyone want to buy a 944 and e39 rack ? Cheap !

Weitse, don't worry about leading the e28 flock down the primrose path of e39 rack & pinion hell. I purchased my e39 right without doing my own home work.

So now what ? I've been looking for a rear steer rack off a porsche or BMW that is some what current. The 928 rack is rear steer but the mounting points are not the best to retrofit to the e28 subframe. Anyone have any ideas ?

Sponge...., if you find that the VW rack works please let me know. I'll do the same if I find a rack that fits.

[Bill in MN]

Check the Pinto/Mustang II racks. Omni racks as well.

http://www.flamingriver.com/index.cfm/p ... /cat65.htm

[Philo]

Sponge and I need a power rack and from what I can see the Pinto stuff is manual. And.., don't think I can mentally deal with putting a pinto rack in my m5

I,m looking at the Jetta / GTI racks.., 911, and one I found online called a w210 .. I think it's a Merc rack.., the guy is doing an engine swap and taking the steering box out to make room for a V8. Check out the link below.

Sponge.., the w210 might be a good option for us.., trying to get ratio info on it.

http://mbworld.org/forums/190e-w201/207 ... -pics.html

Here's one on Ebay - Expensive - http://imagehost.vendio.com/bin/imagese ... 025001.jpg

Here's what the w210 fits

Part #: A 210-460-25-00

Compatible with following models: E300D 96-97, E300D Turbo 98-99, E320 Sedan 96-97, E320 Sedan 98-02, E320
98-02, E420 Sedan 97-97, E430 Sedan 98-02.

[Bill in MN]

Pinto racks were availible with power in their last few years of production.

http://www.racepages.com/parts/steering ... pinto.html


correction: it appears they had it availible from the beginning.

[SpongeBob]

I am working with Unisteer on a custom rack.

I get the width I want, a decent ratio - 2 7/8 turn lock to lock, power, 5" travel - $400 4 to 6 weeks. The one challenge with the e39 rack (other than front steer) was it was too wide - causing some bump steer issues.

Did I mention it was rear steer?

I will keep everyone posted.

SBSP

[Philo]

Not a bad price for custom rack.

I found that the Porsche Carrera 2 / 4 rack is rear steer. I'm now trying to get specs, ratio, length, mount points, etc.. I know the ratio will be ok.., not sure about the width.

Will post as I progress.

[misha]

I am working with Unisteer on a custom rack.

I get the width I want, a decent ratio - 2 7/8 turn lock to lock, power, 5" travel - $400 4 to 6 weeks. The one challenge with the e39 rack (other than front steer) was it was too wide - causing some bump steer issues.

Did I mention it was rear steer?

I will keep everyone posted.

SBSP

Do you have complete specs for your custom rack? Would be cool to see them if you don't mind others seeing them.

[Philo]

Man.., this is a really tough project. Now the Porsche rack wont work because it can only handle 20 bar and the M5 needs 30 due to the power accumulator system for the brakes. Also.., Porsche racks use CHF and not ATF.

So I guess the only remaining option is to go custom with one from Unisteer or flaming river.

I really wanted to use an older Euro power rack.., to keep with the old school Euro theme.

Any ideas ?

[Philo]

God I hate mis information..., I was told by a master tech that the Porsche rack takes 20 bar.... WRONG. It takes 110 bar. I was also told by the same tech that Porsche racks take CHF Petosin.., but after talking to Griffiths (rack rebuilder) they say Dextron III is what i need. So it looks like the Porsche rack will work after all.

[George]

God I hate mis information..., I was told by a master tech that the Porsche rack takes 20 bar.... WRONG. It takes 110 bar. .

Damn, 110 bar. Thats impressive. Too infinity and beyond!!!

I always thought the racks used less pressure.

[MadMaverick]

Here is the link to those spacers:

http://www.teamdfl.com/bmw/e28/steering ... acers.html

Do you think there would be room for a bump steer eliminator simlar to this:



The spacer would change ackerman without moving the rack up.

Do you have any pics of the steering quickener install?

Has anybody tried Z3 or E36 racks?[/img]

[Brad D.]

Here is the link to those spacers:

http://www.teamdfl.com/bmw/e28/steering ... acers.html

AKG Motorsport makes a set of bump steer spacers as well and are priced very reasonably. They should have the same effect as the lowered ball joints you listed. I have a set of those on my s13 and they work quite well and and going to be trying a set of the AKG plates on the e28 soon.

[Bill in MN]

More trial and error. For the 3rd time I redid the steering.

Once I weighed the car I found that it was light enough so as to make a manual rack possible. This meant all of the associated PS junk was removed, saving another 15-20lb. in the process.

I also removed the quickener. The effort needed to steer at low speed was simply too great when mated to the manual rack. The e21 rack isn't really all that pokey and I can live with it.

I have some pics somewhere and will post once I find 'em.

[Mossman11]

Don't want to say what racks may or may not fit because I have no experience retrofitting to e28, but someone mentioned that the e30 rack was a good one to try, in which case E36 and Z3 racks should be fine too because they're practically bolt up to e30's. They're available in 3.5:1 (regular old e36), 3.2:1 (96-99 m3), 3.0:1 (95 m3) and some z3's are 2.7:1 but I think they have less travel not a tighter gearing, so m3's are probably easier to find and the best to use. I have a 95 m3 rack and a 365mm wheel on my e30 and its awesome.

[SamSpade]

Apart from the E21, all 3-series are front steering (i.e. tie rod connects in front of the steering knuckle). As Philo and SpongeBob noted, it wouldn't work since the sharks are rear steering.

[silverfox]

Don't know if any of you are still pursuing this, but I'm part way thru getting rid of the box on my E28 race car. Was told the E39 mounted behind the cross member, but seems it must still push the front of the wheel, damn. Has anyone done a simple conversion yet? Thanks.

[cowlum]

Bumping a blast from the past.

If Philo's numbers are correct, the E30, Porsche944 rack will work if you American purchase a right hand drive rack. For us inthe southern hemisphere, we need to purchase a lefth and rack from the states and flip it up.

[mooseheadm5]

An RHD E39 rack will work. Aaron has one installed in his project car, but it is not ready for the road.