I was going to post this in the repair section, but I guess its gone now... anyway:

After changing out most of my suspension (coilovers, sway bars, rear toe & camber arms, toe bolts) and got an alignment, I'm getting a odd wiggle when hit bumps while I changing lanes. Its a bit hard to explain, but I'm sure is coming from the rear, loses grip slightly, and is really like the car is shaking its ***! A bit odd...

I ask a few friends and the only theory that I am considering that may prove to be true is that I need to put subframe spacers in the rear subframe. My buddy says he ran into a similar problem with a Z32 and that the suspension was to stiff for the stock subframe and so some of the shock was transfering to the contact points of the subframe (he tried to explain it while pointing at the subframe of a 240sx/s13).

So here's my questions:
- Has anyone else experienced this wiggle??
- Any idea what could be causing the wiggle??
- Anyone install subframe spacers on their Z33?? (if this is in fact the solution to the problem)

My coilovers are set to what the factory suggested, sways are set to med. and the alignment is good (i dont know the setting though).

Thanks in advance

 

What tires are you running? Maybe they have a soft sidewall... could be tire pressure. Pretty sure it's not the subframe bushings.

 

I'm running BFG KDW 2 but I was getting the same odd wiggle with the stock rim and tires (actually worse with those).

 

BUMP!

Here's a theory: I'm using the stock bushings one the sway bars. If I change to urethane bushings, think that would fix it??

 

Sounds like you just amplified the natural rear lateral rigidity of the Z.

Maybe some toe-in in the rear would help. Try lower the rear tire pressure a bit so the sidewall become more compliant (ie let the thread move around a bit more so the rest of the car stay put).

 

Maybe you should look into a rear tie bar. When I installed my front, the car feels completely different and very stiff. The rear will be installed this saturday and i'll let you know how that feels. Check your tire pressure like Nihilation said, if you are low in pressure it'll do that.

 

I have the same feeling on my G sedan. I have coupe and z springs with GT spec bars, Dspecs and 350Evo sways with rubber bushings in the front and urethane in the rear. My car will get "wiggly" as well and I have the car aligned using the coupe specs. It may be the tires (snow tires) as the tread is low but I'm waiting for the snow to end before I replace them.

It can be disconcerting when the rear is sliding about.

 

Im running 35-36psi in the rears. Front Sway is set at hard (was set at med)Rear sway is set at soft. Rear is still wanting to break loose

I'm debating re-installing the stock rear sway, but the process of doing so is making me not want to (getting around the exhaust piping is a BIATCH!!)

 

Finally! Someone with a similar problem! So is the car more sliding then shaking? When does it happen for you? Mine ONLY happens when changing lanes or hitting holes on the road.

 

Well if you really think about it, the parts you installed ie sways, coilovers, tie bars, ladder bracing, all these parts make the car very stiff. Therefore it's not intended for public roads because the surface needs to be flat. The setup would be great on a track but the street has bumps, dips, and uncertainties which make it uncomfortable.

I wouldn't worry about it, I sometimes have the same problem I just ignore it. Stiff suspension + city driving = trouble

 

I wouldn't call my suspension stiff, the rates are z and G coupe OE and the Dspecs are set about OE as well. The sways are medium front and rear, maybe I'll play with them. But I'm beginning to think that either my alignment is out or the balding tires are causing the "wiggle" - What is the correct term? Also, how do you tell when a shock is bad - short of removing it?

 

I agree with Kolia - it sounds like your toe is out on your car. A car with Toe Out (that is the front of the tire is out more than the back of the tire as respect to the centerline of the car) will be in an unstable condition on straight line, where as a car with Toe In will be stable (within a certain limit).

 

Changing lanes?

Check the rear toe out, if there is to much tow out in the back, it can make the back steer itself and make the car feel as you describe. Another thing that can cause this is if the car is riding on the bumpstops, but I doubt you are that low.

Chris

 

Thanks for the help. I'll get an alignment and see how this helps. Should i continue with the OE coupe specs or...?

 

I'll try to contact the tech that did my alignment and find out the toe settings. What are the suggested toe settings that may cure this?

 

I got the same problem too lowered on Tanabe Gf210 springs and it is not fun

 

+1 It feels like the back is gonna go out on you! Do you happen to know your toe setting? Can you see your tires bow in slightly? Mine are a bit.

Whats everyone else's toe settings?

 

I have no clue but I need to get an alignment also

 

I had a similar problem in an M3 before. Everytime I'd hit a rut, bump, whatever, it felt like the car was jumping to the side a bit. Turned out to be the RTAB's - common e36 chassis replacement part.

 

What are RTAB??