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Rear Bump Steer Correction Kit

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Old Dec 4, 2007, 09:57 PM
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Rear Bump Steer Correction Kit

For those of you who have the rear bump steer kit installed, where does it go? I bought the kit and it's basically a bushing with an off-center hole in the center sleeve.





The only place I can see this piece fitting is on the inside of the "assist link (forged aluminum" since that directly affects the toe. The stock bushing looks normal with a regularly centered hole. But there's already a factory eccentric adjustment in that location. So if I install a bushing with an off-center hole, how can the adjustment be controlled with an eccentric bolt through an off-centered bushing? And at what position is the bump steer minimized?

Install pics HERE

Last edited by marksae; Dec 25, 2007 at 04:29 PM.
Old Dec 5, 2007, 07:03 AM
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That's where it goes. It works by changing the effective length of that arm. The amount of bump steer is determined by the distance from the pivot point to the ball joint. The position of the pivot point relative to the car doens't matter. The offset bolt is still used to adjust toe. I'm not sure what position the bushing needs to be installed in. Did it come with installation instructions?

Just a guess (i.e. get this confirmed), but I think it should be installed to "lengthen" that arm (offset towards the center of the car). That should create less toe change vs. suspension displacement.
Old Dec 5, 2007, 07:14 AM
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I would like confirmation as well...I agree thats the rt place for the bushing....From what I know, bump steer has to do with the position of the arm relative to the tierod end...the Bushing end needs to be above the opposite end with tires on the ground...so with that said I think the hole goes to the top to raise that end above the tierod end...anyone else..
Old Dec 5, 2007, 07:28 AM
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But it still pivots around the bolt. The effective position of that arm is from the center of the pivot bolt to the center of the ball joint. Offsetting the bushing vertically doesn't change that.
Old Dec 5, 2007, 07:58 AM
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Thats what we are all here to find out..
Old Dec 5, 2007, 08:06 AM
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Well, looks like I had the rt Idea...Its about up and down not side to side,...here are the instruction for the whiteline kit...I would assume the same applies for the works kit..
Fitting: Please read the complete instructions before commencing work.
1. Whiteline recommend that all work be carried out by a qualified technician.
2. It is recommended to measure wheel alignment settings prior to fitment.
3. Raise the vehicle and support the vehicle on safety stands.
4. Remove rear toe-control arm and remove inner bushes from the arm.
5. Fit new KCA388 bushes to the arm.
6. Fit new KCA388 tubes, taking care of the orientation of the off-set hole.
To reduce bump steer, position the tubes with the holes off-set down. (Recommended, refer picture)
To increase bump steer, position the tubes with the holes off-set up.
7. Refit toe-control arm, and tighten all fittings.
8. Lower the vehicle.
9. Test drive the vehicle, and check tension on all fasteners.
10. Measure wheel alignment, and adjust as required.
11. Check & re-tension all fittings again after 100 kms but no more than 200 kms.
Old Dec 5, 2007, 08:14 AM
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Yeah, I just found the same thing.

http://www.whiteline.com.au/docs/ins...278_KCA388.pdf

I still don't get it. That shouldn't make any difference.

Edit: Unless the arm is pivoting around the bushing instead of the bushing pivoting around the bolt, which does make sense. I get it now.

Last edited by GTLocke13; Dec 5, 2007 at 08:16 AM.
Old Dec 5, 2007, 03:28 PM
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Cool! Thanks for the link... so the hole should be installed in the down position to reduce bump steer.
Old Dec 5, 2007, 05:16 PM
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Just for S&G's. Why do you want to minimize bump steer?
Old Dec 5, 2007, 05:22 PM
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My back end is walking around under hard braking. I've almost gone off track several times cuz of this. Several members have reported remedying this by installing the rear bump steer kit, so that's the intent.

In terms of handling characteristics, it's also supposed to help reduce understeer as well.
Old Dec 5, 2007, 06:06 PM
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i got it done in the tuner shop.
Old Dec 7, 2007, 08:07 AM
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Originally Posted by marksae
Cool! Thanks for the link... so the hole should be installed in the down position to reduce bump steer.
I can confirm: offset hole down = less bumpsteer.
Old Dec 7, 2007, 08:57 AM
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Originally Posted by redvolution
I can confirm: offset hole down = less bumpsteer.
So Will, do you have this kit installed on your car? If so, how did it affect braking stability?
Old Dec 7, 2007, 11:10 AM
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I thought bumpsteer correction was to alleviate the unwanted toe in under suspension compression (power and/or body roll).

I thought Mitsu designs the bumpsteer in to make he car a little more idiot proof and keep lots of itiots screwing around from spinning out into bridge abutments, etc.

I may be wrong, but that's what I thought.

and yes, bushing hole down = less bumpsteer.
Old Dec 7, 2007, 06:17 PM
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Originally Posted by marksae
So Will, do you have this kit installed on your car? If so, how did it affect braking stability?
I installed the whiteline kit last summer in conjunction with the rear trailing arm bushings. Besides making the car more neutral during cornering, the combination did stabilize the rear under heavy braking. It still wiggles a little, but not as much as it used to. Definitely less of a pucker factor. ... if only I could say the same of the last set of pads that I used. I'm still on my stock springs and struts.

l8r)


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