Back story. Bought neglected mini in June. Did major refresh over last 4 months. Including: IE Camber plates, new inner/outer ball joints, inner/outer tie rods, front/rear sway bar end links, powerflex control arm bushings, H&R rear sway bar, new passenger side engine mount. Alignment was done with the two tape measure method set to 1/8" toe in.

Before I did all the work, the car had a small amount of slop at 0' on the steering wheel. Maybe a half inch total wiggle that didn't affect the wheels. This still exists.

The real problem appears to be when I left off the gas, the car pulls to the right, and when I get on the gas it pulls to the left.

Searching has resulted in "control arm bushings" but I'm pretty sure that's not my issue here. Anyone have any other ideas? Could it ALL be in the steering rack and tied back to the slop at 0'?

 

There should be ~1* of slop on either side of center. You can feel it with the car off by jiggling the steering wheel left and right, at least in my experience. I think it has to do with the bit of play in the steering u-joint. If you want to go hog-wild, perhaps replacing the joint and adding a polyurethane rack bushing might help a little.

The torquesteer is best diagnosed by looking at the control arm bushings. If it's not those, jack up the car and jiggle the wheels on a vertical axis. Maybe the wheel bearings are bad? If those are all good, and you're confident in your alignment, you're just experiencing the woes of a non-LSD car.

 

Control arm bushings are powerflex with less than 50 miles on them, I really doubt that could be the case.

I had a mini some years ago and it definitely didn't exhibit this amount of movement. I'm not talking about it pulling left/right when hammering on the gas, I'm talking about tip in. Just barely getting on/off the gas will put the car left and right.

I'm going to get the car off the ground soon to check for movement/slop, but I was hoping this was an issue seen elsewhere. I've driven cars that have needed significant suspension work and still never experienced anything like this.

 

do you have an lsd in the car?

 

You may want to try "zero toe" up front. Check the installation of the IE plates that they are orientated towards the imaginary center line of the chassis.

The on throttle, off throttle behavior is likely compounded by whats going on in the rear. You may want to also try" zero toe" and take the time to really get this exact on both sides.

In my experience when you can set the car to a relaxed neutral on the alignment rack - everything becomes more enjoyable and stable when under WOT. The forces work diagonally- so if the car is going front left under power - investigate whats going on in the right rear. You don't want the car being pushed and tracking from something in the rear that is out of adjustment.

Post up your findings from the alignment rack and Im certain that you will see some improvements with suggestions here.

 

Thanks, I think you've probably got the most reasonable answer. IE camber plates were installed correctly. We've got lots of experience doing tape measure toe settings, but not on the mini, its possible its more touchy. Maybe moving closer to zero will help with this. I guess that should be step one and will be easy to address.


Also, no LSD as far as I know. The previous owners weren't the kind to install one and VIN indicates no. Haven't done the wheel spin test to see.

 

The other 3 steps we did:
1. Underinflate tires slightly - 30
2. disconnect sway bar drop links front and back - zip tie them secure just for initial adjust and test drive
3. Work on the rear alignment first. Zero toe and 1.5 negative camber. Don't get fooled with "total toe" being zero - adjust so that you can get a match equal on both sides. This is the foundation of predictability when under power. When test driving, the car should tracks straight under power and initial brake bite - barely touching the steering wheel.

Then go back and reattach sway bar links and check to see where the front is at. The IE plates do not always match exactly! See what max front camber you get with yours and report findings. Initially I got .5 on one side and .8 on the other when installed out of the box. Slotted the tower ever so slightly and got them to match on both sides. WORLD of difference for throttle behavior.

When your all set, bring tire pressures back to baseline for yours. Runflats or otherwise.
Good luck. You'll get it dialed in and will love it.

 

Thanks for the great info. When the car is broken in I'll take a closer look in the method you suggested.

I got the car off the ground today, inner ball joint was loose, tightened it up and test drove it. All good! Figures. Still have slop at 0' which I should expect going forward, but even that is reduced. This is the car I remember! Thanks for the input!

 

Some good suspension discussions here, going to move to the Mod Suspension section.

 

I'd like to put my two cents in here, since I've been doing a lot of reading around today, particularly about the relationship between the steering axis and scrub radius at the front.

Have you modified the wheel and tire setup? If you space the wheels out far enough, you can encounter a positive scrub at the front, which could explain the pulling in different directions under accel and decel. These cars come with just a hair of negative scrub at the front, which compounds the toe-in when stopping. But, if you space the wheels out too far, you encounter positive scrub, and the wheels toe-out when stopping.

Scrub radius is a fascinating subject, have a look.

https://en.wikipedia.org/wiki/Scrub_radius

 

If you use spaced wheels how can you compensate for the different scub radius (and the steering wanting to pull too much either left or right under acceleration)? more front toe in? front toe out?

What about camber or caster?

Thanks