Post Z3-Rack Install Problems ::: FIXED!

[AndrewBird]

Bump steer is caused from the tie rod and control arm having different pivot locations. The arcs they travel through have different radii and locations, so the change in distance relative to the centerline of the car changes at different rates.

You would want to put the spacers in where it makes the rack sit with the tie rods as flat as possible. The closer to flat they are, the less change in distance they will have compared to if they started out angled up or down.

[iwantspeed]

UPDATE

So I finally got back from my trip and was able to tackle the rest of this beast. Upon getting my car on jacks I noticed a few things:

1. Alignment and Auto-Centering
Yes, it came as to no surprise, my alignment was VERY toe-in /-----\. What I noticed before of just one wheel being off ended up being both wheels off with one way worse than the other. After some 20+ hours of researching steering geometry, castor, toe, and self-leveling; I've learned these key things.
Toe-in causes the wheels to be in a perpetual gridlock for grip and causes the wheels not to be able to self level, as the wheel opposite the turn (left turn/right wheel or right turn/left wheel) will be continually applying force into a steer. This in turn causes "memory-steer" which is often confused with bump-steer. Memory steer is the aspect that, if you steer to one side, the wheels will steer themselves back to that side because the opposite wheel will lock into more grip and continue the steer, even after the steering wheel is let go (and presumably, in a balanced system, will auto-level). Ultimately, this causes the car not to auto-level while traveling forward.
Toe-out, \-----/ on the other hand, will place the wheels in a position to where the castor will cause the wheels to be in a perpetual state of correction as both wheels are struggling to steer inward because of the nature of forward travel vs. grip of the wheel, leading to more stability, especially at higher speeds. After I aligned the wheels to correct specs as stated in the e30 Bentley manual: 1/32" toe-out (or close enough to that), my auto-correction worked perfectly fine.
I also noted that when I was toe-in, auto-leveling worked while I was traveling reverse, but now it work vice-versa (toe-out; auto-leveling while going forward).

2. Binding Knuckle. Bad.
I noticed the u-joint closest to the firewall (the top one; connected to the steering column spline, not the rack spline) was binging on itself from the increased angle of the rack; I ended up grinding the squared-off joints with a dremel to round them out, and a little inside the "U" and it freed up enough clearance. Applied some WD-40 afterward for safe measure and I'm free to enjoy my rack.

3. Bump-steer
After the barnyard string alignment and knuckle-binding issues were fixed, I took it out for a test drive and noticed NO BUMPSTEER WHATSOEVER with the spacer on top of the rack. It was better than even my stock e30 rack which had loads of bump steer. I made sure to drive over plenty of speed bumps and took an uneven back-road at higher speeds (60-70MPH): no drama to report.
As stated before, my "bump-steer" was actually memory-steer caused by my toe-in condition, and was confused as bump-steer. I also used the e36 tie-rods (which I highly recommend) because they are beefier, and have better tie-rod joints; these are probably the cause of my decreased bump -steer as my e30 rods were shot

4. Power steering stuttering.
I still have slight stuttering from my power-steering going lock-to-lock; not a full "OMG, it feels like power steering is gone" kind of stuttering, but just slight... Difficulty if that makes sense. As I had my car on jacks, I was spinning the wheel lock-to-lock and noticed my air bubbles coming out, so I put my money on air in my system; either it will most likely bleed itself out due to the nature of how BMW designed their power-steering system, or I just have to do a flush. No big deal as it hardly effects driving



TL-DR
My problems were:
1. Alignment was toe-in causing auto-centering not to work; aligning my wheels properly to slightly toe-out (1/32" toe-put) fixed my centering issue
2. Knuckle was binding; grinded down u-joint with dremel; no more binding.
3. No bumpsteer at stock height with spacers underneath rack. Stability better than even my e30 rack
4. Still have some air in system



same mistake on the website



https://www.r3vlimited.com/board/showthread.php?t=298272&t=298272


https://www.diyauto.com/manufacturers/bmw/generations/3-series-1/diys/post-z3-rack-install-problems-by-jinormusj


im trying to figure out if i get less bump steer with the spacers below the rack..


i believe i will since my car is lowered.



at ride height i dont want the tie rods pointing up from the steering rack


and your inbox is full

[JinormusJ]

Post Z3-Rack Install Problems

UPDATE

So I finally got back from my trip and was able to tackle the rest of this beast. Upon getting my car on jacks I noticed a few things:

1. Alignment and Auto-Centering
Yes, it came as to no surprise, my alignment was VERY toe-in /-----\. What I noticed before of just one wheel being off ended up being both wheels off with one way worse than the other. After some 20+ hours of researching steering geometry, castor, toe, and self-leveling; I've learned these key things.
Toe-in causes the wheels to be in a perpetual gridlock for grip and causes the wheels not to be able to self level, as the wheel opposite the turn (left turn/right wheel or right turn/left wheel) will be continually applying force into a steer. This in turn causes "memory-steer" which is often confused with bump-steer. Memory steer is the aspect that, if you steer to one side, the wheels will steer themselves back to that side because the opposite wheel will lock into more grip and continue the steer, even after the steering wheel is let go (and presumably, in a balanced system, will auto-level). Ultimately, this causes the car not to auto-level while traveling forward.
Toe-out, \-----/ on the other hand, will place the wheels in a position to where the castor will cause the wheels to be in a perpetual state of correction as both wheels are struggling to steer inward because of the nature of forward travel vs. grip of the wheel, leading to more stability, especially at higher speeds. After I aligned the wheels to correct specs as stated in the e30 Bentley manual: 1/32" toe-out (or close enough to that), my auto-correction worked perfectly fine.
I also noted that when I was toe-in, auto-leveling worked while I was traveling reverse, but now it work vice-versa (toe-out; auto-leveling while going forward).

2. Binding Knuckle. Bad.
I noticed the u-joint closest to the firewall (the top one; connected to the steering column spline, not the rack spline) was binging on itself from the increased angle of the rack; I ended up grinding the squared-off joints with a dremel to round them out, and a little inside the "U" and it freed up enough clearance. Applied some WD-40 afterward for safe measure and I'm free to enjoy my rack.

3. Bump-steer
After the barnyard string alignment and knuckle-binding issues were fixed, I took it out for a test drive and noticed NO BUMPSTEER WHATSOEVER with the spacer on top of the rack. It was better than even my stock e30 rack which had loads of bump steer. I made sure to drive over plenty of speed bumps and took an uneven back-road at higher speeds (60-70MPH): no drama to report.
As stated before, my "bump-steer" was actually memory-steer caused by my toe-in condition, and was confused as bump-steer. I also used the e36 tie-rods (which I highly recommend) because they are beefier, and have better tie-rod joints; these are probably the cause of my decreased bump -steer as my e30 rods were shot

4. Power steering stuttering.
I still have slight stuttering from my power-steering going lock-to-lock; not a full "OMG, it feels like power steering is gone" kind of stuttering, but just slight... Difficulty if that makes sense. As I had my car on jacks, I was spinning the wheel lock-to-lock and noticed my air bubbles coming out, so I put my money on air in my system; either it will most likely bleed itself out due to the nature of how BMW designed their power-steering system, or I just have to do a flush. No big deal as it hardly effects driving



TL-DR
My problems were:
1. Alignment was toe-in causing auto-centering not to work; aligning my wheels properly to slightly toe-out (1/32" toe-put) fixed my centering issue
2. Knuckle was binding; grinded down u-joint with dremel; no more binding.
3. No bumpsteer at stock height with spacers underneath rack. Stability better than even my e30 rack
4. Still have some air in system

[Wanganstyle]

If you have not even completed a single rack swap successfully then perhaps hold off on the comments.......

Z4 rack is easy as hell to install and they are more common/newer parts. Z3's are old cars compared to z4 and the market cost of a good z3 rack is MORE than the z4 units.

Z4 m cars have hydrolic powered steering- only the non-m cars have electric assist in the column.

Why would you install a power rack just to delete the power?????? Not very logical when there is a newer non powered option avail.

E46 m3 rack is a good option if more angle is desired and power also.


Sent from my GT-N7100 using Tapatalk 2

[JinormusJ]

Post Z3-Rack Install Problems

I would go Z3

Z4 rack swap is much more involved; I know Wanganstyle here has done it, but for a daily driver, it is a little excessive. With it being only marginally better than the Z3 rack; for the price and difficulty of the swap (not to mention rarity of the rack) you'd be more happy going Z3 and keeping power steering.

However, wouldn't hesitate to put a Z4MC rack in a power-deleted track car

[mulletman]

Interesting. I want to do a rack swap... But I can't decide between Z3 and non-powered Z4.

[JinormusJ]

That's why I'm not worried about the bump-steer aspect as my swap isn't even drivable and shouldn't be compared to a running, driving car.

The toe is causing memory steer, which is very hard to differentiate between bump steer. Until I get an alignment, I can't give any definitive results about how it drives

[Wh33lhop]

I thought this was a given; I haven't driven the car since parking it last night immediately after my rack swap, nor will I until I fix the toe and get an alignment. I previously stated the car was unsafe and inoperable in its current state. Wouldn't make much sense to drive it if I already know that much

Fair enough. I only read the last post and the thread title.

I think crazy toe will exaggerate your perceived bump steer, as well, if that makes sense.

[JinormusJ]

How bad is the bump steer?

enough to toss my wheel half a turn on uneven gravel roads; on a straight road it wasn't too bad, maybe 1/8 turn, but this is all speculation until I get my alignment dialed in and further tackle my memory steer and auto-correction issues.

FWIW, I drove a friends Z3 rack'd e30 and there was little to no bump steer, just more road input from the linear rack. I think he mounted his spacers beneath the rack though, not above it

[mulletman]

How bad is the bump steer?

[JinormusJ]

Post Z3-Rack Install Problems

They are linear, so it won't truely return to center.

Neither do Progressive racks

Let go of your wheel after a turn and see if you don't have to put some input to center it. All racks will require a certain amount of user-centering at low speed. If anything, a normal e30 or e36 progressive rack will require MORE user-centering than a linear rack because the center on a progressive is much more numb to road input than a linear rack is.

Stop driving the car immediately

I thought this was a given; I haven't driven the car since parking it last night immediately after my rack swap, nor will I until I fix the toe and get an alignment. I previously stated the car was unsafe and inoperable in its current state. Wouldn't make much sense to drive it if I already know that much

[djmossm42]

I was under the impression that Z3 racks do not return to center as they are linear.

They are linear, so it won't truely return to center.

Sent from my SGH-T769

[Wh33lhop]

Stop driving the car immediately. Fix your damn toe until both wheels look reasonable, then get an alignment. Do that FIRST and that will likely alleviate a lot of your problems. Then worry about binding.

[JinormusJ]

Post Z3-Rack Install Problems

Well, the front definitely needs an alignment bad; with the steering wheel centered, the left wheel will track straight while the right wheel is toed in

Just think of it resembling this from above:
|----\

I have no doubt that a lot if not most of my auto-correct and memory steer issues are coming from an improper alignment; I did not align the the tie rods after installing the rack (although, I tried my best when I replaced the drivers side rod). This shows, as the passenger side tie rod is still on "Z3 Toe-Spec" while the other one is eye-ball aligned if that makes sense. Right wheel is toed in about 10*

Due to the nature of physics, a balanced system will return to lock regardless of the ratio or nature of how the gears are set (linear vs progressive) as the force behind the front wheels (the entire car), will shift the wheels the direction the force is traveling (ei, if you turn and let go of the wheel, the force of the car is no longer in a turn, and is traveling straight, and thus will center the wheels. In an unbalanced system, the force of the wheels in a turn can be greater than the force of the shell, thus the rack will not center.

I can hear tire screech from the wheels going straight as slow as 10mph. Also, my left wheel is wearing in little quarter side patches near the outside of the wheel

My power steering studdering has seemed to go away for the most part; I uncapped the reservoir, and spun the wheel lock to lock to bleed the system, during which I found out the rack was off-center when installed; my left lock was 1.1 turns, and my right lock was 1.6 turns. I ended up just taking the wheel off and adjusting, moving it a spline closer to the left, until I was a perfect 1.35 from center-to-lock.

I also think I have binding causing a flat spot (or better described as a stiff spot) in my power steering as off the car, the rack spun freely; once back on the lift, I will spin the wheel to check for any binding spots on my knuckle, as I expecting some in theory


So glad that these issues are at least easily diagnosable.

[AndrewBird]

Most of the auto centering comes from caster built into the front suspension. Think of a caster wheel on a shopping cart turning back straight when pushed forward. Same thing on a car.

A bad alignment will definitely cause what you are describing. Yes, you can't adjust caster directly on and e30, but toe will have an effect on caster and camber. Roughly align it the best you can with a tape measure then drive it to get it aligned.