Z4 non powered steering rack fits e30

[Wanganstyle]

Thanks for the information on this. I picked up a Z4 manual rack and thought I would contribute a few measurements I took from it.

Travel: 144.6mm
L2L: 3.0 turns
Rack ratio: 48.2mm/revolution
Steering ratio: 14.5:1 (e36 uprights)

18.9mm shaft, 48 spline (could be one or two off here as it was a quick check and hard to keep count). Seems like it's probably 3/4"-48.

Awesome thanks for contributing.

What would the steering ratio be like with e30 uprights (our racecar)- how did you calculate it?

[mike156]

Just took the advertised ratio of the e36 (15.6:1) multiplied it by the E36 rack travel/rev (45mm/rev) and divided by the Z4 travel/rev (48.2mm/rev).

No idea how the e30 compares but I imagine these numbers are out there for the E30. I'm excited to see how it goes as my other car is an evo. The 2.2 turns lock to lock and 12.5:1 steering ratio makes this care feel crazy slow on steering. I think the 14.5 should be a good compromise for effort and quickness on the manual rack.

I ordered up the U-joints and I'll update here on how they fit. Should be under $300 for the rack and steering shaft to drop (hopefully) 15 pounds and improve the slow steering.

[Wanganstyle]

Just took the advertised ratio of the e36 (15.6:1) multiplied it by the E36 rack travel/rev (45mm/rev) and divided by the Z4 travel/rev (48.2mm/rev).

No idea how the e30 compares but I imagine these numbers are out there for the E30. I'm excited to see how it goes as my other car is an evo. The 2.2 turns lock to lock and 12.5:1 steering ratio makes this care feel crazy slow on steering. I think the 14.5 should be a good compromise for effort and quickness on the manual rack.

I ordered up the U-joints and I'll update here on how they fit. Should be under $300 for the rack and steering shaft to drop (hopefully) 15 pounds and improve the slow steering.

Former evo 8 owner here :)

What steering shaft parts did you order? Our racer has a sloppy bushing by the steering wheel hub mount and it's bothersome on track

[mike156]

Flaming River part number (options available from other suppliers though)
fr1931 (rack side)
fr1964 (column side)
3/4" / 1" DD collapsible shaft

Not positive these are correct yet though.

[mulletman]

Flaming River part number (options available from other suppliers though)
fr1931 (rack side)
fr1964 (column side)
3/4" / 1" DD collapsible shaft

Not positive these are correct yet though.

You're awesome. Thanks for all of the info!

[mike156]

Verified the rack spline today, 3/4"-48 fits great. I got a great deal on a forged non-split style u-joint off fleebay but I wish I had hunted around a bit for a split style clamp like the OEM. I would bet they are out there as it looks to be a common size.


50k mile rack from a rear ended Z4 - $150 shipped
Rack U-joint - $37 shipped
DD Slip shaft - $30 shipped
Steering Column U-joint - $100 shipped (ouch)

Not bad as the shaft alone is $280 to $350 from vendors. No doubt, the billet Flaming River joints are going to be higher quality and is where a lot of the price is. FWIW, the rack u-joint is marked UJ-013 but that doesn't really turn up anything on google. I imagine it's probably some china made piece and maybe the materials are complete junk, but visually it looks solid.

[jwal]

I am very interested in doing this as my steering rack is dead, and i dont really want power steering in my 318is anyway...Im just trying to get a better idea of what needs to be done

[Wanganstyle]

Try reading the first post carefully and doing more research. You'll find all the data needed.

Our setup has taken 40+ hours of racing and I would not have any other rack installed

Sent from my SM-N900P using Tapatalk

[jph]

I have picked up a Z4 rack and am mulling over the options for setting it up properly in the car. Here is what I have come up with from Flaming River:

3/4"-48 x 3/4" DD stainless u-joint
17mm-54 x 3/4" DD stainless u-joint
18" 3/4" DD stainless shaft (cut to length)**

**18" is the shortest length available from FR and from other members' pics it looks like you might only need +/- 6". In theory you could possibly get three shaft out of one piece, recouping some monies and spreading the shaft cost across a few members. Guess this is what forums are all about, right??

All of this comes to $250 plus an additional $19 for shipping. The ONLY used steering shaft I can locate is $140 on eBay. I think the additional $100 is worth it to be done more than right. I could probably knock the total cost down a bit by going with a different material, but for the maybe $50 I would save stainless is a solid choice to me.

I haven't actually checked the spline counts needed as I was basing these dimensions on the member a few posts up who verified sizes. I will most likely be going the Flaming River route in the next few months as it's simple and straightforward:

1. Mock up u-joints on column and rack
2. Measure distance needed for shaft
3. Cut shaft to desired length
4. Bolt it up and go

[89325iturbo]

Any new updates on this, from people who have installed it? With what combination of parts did you use for the steering ujoint? Or modify the stock z4 piece.

[R1dd1ck913]

Im interested too. Would love to know more.

[totheredline]

Installed in my m30 swapped car. Really really easy to turn compared to a non power e36 rack and wayyyyy better feel. Andddd the ratio and angle is beautiful. Pretty much bolt in besides cutting the shaft to length.

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[jph]

Any new updates on this, from people who have installed it? With what combination of parts did you use for the steering ujoint? Or modify the stock z4 piece.

I've had the rack waiting to go in and I had Tyler at Arc Asylum make me a custom steering shaft using Flaming River joints and a collapsible shaft. The collapsible shaft will give me some wiggle room on fitment length and is also safer in the event of a front end collision. I'll update here once it's all installed.

[Brian7]

So if E36 inner and outer tie rods fit the Z4 rack, does that mean E30 inner and outer tie rods will fit the Z4 rack as well? Since E30 inner and outer tie rods fit E36 racks I don't see why not. I have brand new E30 tie rod assemblies ready to go.

[Brian7]

Well, I may be the first to report if they fit. Got a Z4 rack on order :D