Steering Rack swap?

[nando]

got the ix tie rods

so, the good news - the total length of the E30 ix and E46 xi racks (tie rod end to tie rod end) is basically the same, about 55".

the E30 tie rods will mount to the E46 rack. however, they are too long. it may be possible to shorten them but I don't know if it will be enough. also, I don't think the lock plates for the E30 will work, and I don't know how the E46 tie rods lock to the steering rack (there's no locking pin or plate that I can see).

the E46 tie rods would work but the pin that fits into the strut housing is too large. Possible solutions? turn it down? drill out the hole in the E30 strut? swap ball joints? find a similar tie rod end with the smaller ball joint? Maybe from the E36?

I also checked the steering ratios and total travel, approximately. the E30 rack moves 1.5" for each revolution and has 5.5" of total travel. the E46 rack moves 2" for each revolution (from center), and has 7" of total travel. I don't know if the E46 rack is progressive or not, but it's definitely a step up.

[D-rock]

^ good info!!

[nando]

yeah, but it's never going to be simple.

- the subframe needs to be modified (drilled, welded, etc).
- the tie rods need modified or pieced together
- the steering linkage needs pieced together or modified

luckily used ix subframes are cheap on ebay..

[Nisse Järnet]

Nice info! Im 99% sure that E36 uses the same "pin-size" as E30.

[nando]

yeah, if the outer portion is shorter than the E30 ix, then it could be the answer.

I think I can shorten it enough to make it fit, but then I don't think there will be any room left to adjust toe and that would be no good.

[Julien]

Are there no racks that are internally the same dimensions as e30 racks but quicker?

[stonea]

I don't think so. I've been asking around but I've had no luck finding someone who would be willing to make a quick ratio rack for us.

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[nando]

Are there no racks that are internally the same dimensions as e30 racks but quicker?

No.

[iXguido]

Bumping this up. Anyone made any progress?
Just for clarity it sounds like there would not be any bump steer issues with the xi rack since the overall lengths are the same? The major hurdles are the mounts and tie rods?

[nando]

not really - I'll probably do it after my engine build is done (which at this rate will take me 3 more years, lol).

I figured out that you could just use the E46 xi tie rods - they are the right length, but the ball joints are bigger. You would have to have the tapered holes in the struts reamed out to fit the bigger ball joints (it's not a huge difference, there should be plenty of material left).

The rack is actually a little longer - so there might be some bump steer, but I think the trade off will be worth it. I've measured the mm/revolution a couple times (although I always forget the numbers) it was like 2-3x faster than the ix rack. If you're used to driving a modern BMW you will appreciate the difference. The E30 always feels like a bus the first couple times I get back into it.

[Kershaw]

What's the difference in balljoint size? Could you ream it out yourself with a hand drill?

[nando]

It's a mm or two - no, because the hole is tapered and it has to be sized precisely.

[nando]

BTW, I talked to John (ForcedFirebird) and he can modify the struts to make the E46 tie rods fit. So if you're doing coilovers, something to consider - but you'd want to get your ducks in a row regarding mounting it to the subframe (needs modifications). Garagetastic should be able to help with the steering linkage, you just need to give them the right measurements.

Basically, it's perfectly feasible - but nobody has done it yet. Also note that you want the later E46 330xi rack, not the early one. The early one had a slower ratio and poor feel.

[stonea]

Thats what I was going to do. I'm eventually going to convert to coils and send it to John to get everything done, but I'm not willing to commit yet.

[iXguido]

Thanks for clarifying everything. I'm hoping to try this soon