handling issue, need advice

[johny1111]

I have bought a 95 240sx recently. The car has had some accidents but i got a good deal on it so i went for it. It drives fine, goes straight doesnt pull to the side, and there is very little wheel vibration. It's lowered (roughly 2.5") on tanabe coilovers and it has 235 tire at the front and 255 at the back (not sure of offsets).

My problem:Sometimes when i go over manholes or potholes on the road, the car shifts a little to the side. It only happens if one of the rear wheels goes over, and seems to only happen at certain times depending where the wheel hits the hole on the road. If Drivers side wheel hits a hole, the car shifts towards drivers side, and if passenger's side wheel hits a hole then car shifts toward the passenger. The shift is minimal but can be felt. It also seems if the tire is aligned nicely with the hole edge, it car doesnt shift even if the hole is big. I havent experienced this in other cars before that's why i wanna get your thoughts on this.

I hope someone can shed some opinions and suggestion on this.Thank you

[onosqv]

coilovers new? have you tried stiffening or softening the dampening in the rear to see if it helps? or maybe need some subframe spacers to help w/ the problem...

What's your alignment specs in the rear?

You could be experiencing bump steer... lowered car -> "lots" of negative camber -> one wheel looses traction (i.e. manhole) -> other wheel pulls the car one way...

[johny1111]

thanks for the reply

The coilovers came with the car, they look like they're still in good shape. They're the low end tanabe sustec, only height adjustable (no dampening adjustment) and the car is pretty low.

How do I find out alignment specs? Take it to a shop?

It totally feels like bump steer.

I noticed the fronts or rear wheels are pointing more inward than the rears. The fsm states that that's normal.

[onosqv]

You "should" be able to find an alignment shop that will give you a free reading - i.e. tell you ur specs b4 you align.

Are those coilovers single height adjustable or dual height adjustable (i.e. able to adjust height w/o compressing the spring).

If they are only single height adjustable... that could be the problem right there...

[johny1111]

i really appreciate your help broke

I'm not sure if the coils are single or dual adjustable, i'm gonna try to find out tonight.

But another thing i noticed is that my toe angle is quite visible. When i look at the tire from the top i can clearly see how it's pointing towards the middle of the car (on both sides in the rear). Can the cause be excessive rear toe angle because of the car being lowered?

If so, can I adjust this myself, or do i have to take it to a shop?

[onosqv]

I'd take it to a shop. If you have factory links (i.e. factory toe rods/camber arms/etc), then there is only gonna be so much the shop can do.

And yes, when lowering your car more than 2", it is always recommended to have adjustable links. You could eyeball do it yourself.. but this is usually only to make it fine to the alignment shop.

[crzycav86]

You could be experiencing bump steer... lowered car -> "lots" of negative camber -> one wheel looses traction (i.e. manhole) -> other wheel pulls the car one way...

I agree that what you are experiencing is bumptsteer, but this explanation of bumpsteer isn't completely correct.

A lowered car with an insufficient alignment(like your car) will have a large dynamic change in toe when hitting a bump. The change in toe is what causes your car to wander, not a loss in traction.

You need adjustable linkages. Check out splparts.com and buy their rear traction, toe, and upper arms. Then get it aligned. That will fix your problems

[onosqv]

A lowered car with an insufficient alignment(like your car) will have a large dynamic change in toe when hitting a bump. The change in toe is what causes your car to wander, not a loss in traction.

That makes more sense .

[johny1111]

thanks for the info crzycav

So I guess i shouldnt even waste money on alignment unless I get these things first? Is that the case?I cant get my car aligned with stock parts?

Do I have to get all 3? Man I need 700 bux in parts What if I just get rear toe arms?

[crzycav86]

I was under the impression that you already aligned it. Get it aligned first.

I still have the stock linkages, and I don't have any problems. It mainly depends on how low your car is. Mine still has about an inch of fender gap all around, and i was able to have it aligned properly(with a little extra rear camber)

[sleepyRPS13]

losing traction is more like wheel hop. =J