7sins2000

So I have an 00 with a 2jz swap and import muscle front end relocation kit for the rack and sway bar. It has no rear sway bar. When letting off the gas sometimes after a decent pull to shift it almost always feels like the back end slides out to the right. Then sometimes, not always it slides right or left once it hits a bump or crest in the road. It feels like it's steering with the rear.
to counter this I have installed solid diff bushings, rear bump steer arms, full poly bushing kit for the rear only and hks coil overs all around. I just completed an alignment today and got the rear completely center with -.15 toe and 1.5 degree camber.
i did not drive this car before I did the swap so I don't know if it's just a swap car thing or a my car thing. Each mod has decreased the problem but it's still scary to drive because it's so random and intense.
any ideas on what could cause this?

Car Analogy

One thing that pops to mind is the rear tires. This car is especially sensitive to matching rear tire diameters. If one tire is a little off from the other, rear will pull one way on the gas, other way off the gas.

Most common reason tires aren't same diameter is air pressure. Make sure they are both exactly the same.

Make tires are both the same brand, and same age. Some have gotten brand new tires, one made in different country than the other, and had minor differences in size that would cause the issue.

Obviously uneven wear can cause this as well. You can compare sizes by wrapping a string around one tire, mark size, then do same other side, make sure same.

Rule out the tires before digging deeper...

7sins2000

Tires are pretty hard 255/40/18 nankings with 10/32s tread. not good for any sort of real racing, but I'm just trying to shake down the car driving it around town before I buy my final tire and wheel setup. Pressures are 32, just checked while doing the alignment.

s2000Junky

You have added more weight over the nose i assume with the swap, which means your unweighting the rear even more under braking. A tire with soft sidewalls and tall squirmy tread is not your friend in this scenario. Also the diff responds to on/off throttle in how it locks/unlocks the rear tires. This can cause a novice to spin in a turn, and feel unsettling at speed. You might try raising the front end of the car 1/8-1/4" to bias the weight more to rear then it is, adding more stability to the rear overall. You also need to make sure your bump steer kit has proper spacers to align the toe rods. You do not want the rear end to toe out when you off load it from letting off gas or braking.

ZDan

When my car was doing this it was due to the rear toe having slipped from ~0.2° total toe-in to upwards of 1° total. The car was all over the place...

Negative toe is toe-OUT, you sure it's not positive toe-IN? Also, 0.15 *what*? Inches, degrees, millimeters, furlongs? And is it 0.15 per side or total?

From what you describe it sounds to me like either one bad rear tire (internal defect can cause a tire to pull hard even if both rears look identical) or rear toe.
If your rear toe is 0.15 inches per side, that's 0.3 inches total, or 0.69° total. That would be excessive.
Even 0.15 inches total, for me that's on the high side.

The early cars ('00 - '03) have funky rear geometry where the rear toe changes a LOT with bump/droop travel. In my experience the adverse handling characteristics this gives are *greatly* exacerbated the more static rear toe-in you run. I would suggest no more than 0.2° *total* rear toe-in, or 0.087 in. total, 0.044 in. per side.

You could easily see if it's the tires by swapping the rears left/right and see if the rear end moves in the opposite direction when you lift to shift. That would indicate a bad tire.

B serious

Negative toe? but....why?

7sins2000

its 0.15 degree each tire positive 1.5 degree negative camber sorry, spec is 0.22 but i have almost everything solid in the back so i wasn't as aggressive with it.

i have the front suspension raised and have played with preloading the front springs to get it to load the rear more, no effect. it is currently 0.4" higher in the front, preload is reset to HKS recommended spring height currently. rear bump arms have the forum popular setup of 2 spacers on top one on bottom i have read on here, i may try moving them around for any results.

i will try flipping wheels tonight and see what the result is, im also thinking on replacing the front bushings with a poly kit, maybe the compliance bushing has failed and is causing this.

so yes, tonight i will flip the wheels around and take it out again, if that doesnt do anything im going to install poly bushings up front and realign and see how it drives unless somebody else has some more great input!

ZDan

Spec is too high IMO. You're good with 0.15° per side, 0.30° total rear toe in but for me that's kinda at the max I would run. I run 0.20° and have run less than that without issue. More rear toe accelerates tire wear and makes the handling nonlinear and weird. Bad for everything...

7sins2000

I'll do that spec when I get the new bushings installed this weekend and I do the alignment. Should know by Monday how it's changed. Bushings come tommarrow.

7sins2000

Just got the front end apart tonight, front camber bushing was separated from the arm. Hopefully this bushing kit takes care of my problems since I actually found a faulty part.