dws6

The car gets really loose and uncontrollable under hard acceleration (2-3rd gear) and feels like its stepping side to side. It gets worse as speeds increase. I could swear to you if I stay in it I would wreck the car it gets so bad. The same speeds not under WOT its fine. Ive had it to 120 NOT under WOT and it feels ok.

It started when I Just recently made the following changes while I was waiting on the new wheels. Mods at the time consisted of adding the Strano hollow sways 35/22mm, CTS-V front breaks, Hawk pads all around, narrowing the factory rear, pulling the rear spring isolators, installing an adjustable PHB and of course the new wheels and tires.

Prior to this I put new koni and strano springs and everything was fine. It didn't start until I did the above mods. The car only has 14k miles on it so LCA bushings are not worn out.

Any Ideas? Its scary under load so I really need to figure this out ASAP. Any and all help is appreciated.

dws6

no one has any suggestions? Can sway bar binding cause something like this?

JD_AMG

IMO if nothing else the easiest/most logical thing to do is one by one take off the things you replaced and put the stock pieces back on for now to see which piece is causing the issue (im talking about the rear bar, adjustable PHB and wheels, although maybe narrowing the rear had something to do with it - since its only under WOT this makes me want to point at the differential acting weird.)

HioSSilver

iTrader: (8)

My diff made my car sway.

dws6

how so? can you elaborate?

ZForce1

I'd definitely look at the PHB and LCA attach points and jam nuts where the adjustment is. Those aftermarket parts are bad for coming loose. I wish they came with either lock washers or even better safety wire holes.

z28bryan

iTrader: (7)

At what angle is the PHB at when in loaded position?

Also, how did you narrow the factory rear and what benefit does that have? I've never heard of that before. It sounds interesting.

Coppertone

Even through you only have 14K miles, those bushings are still 14 years old. 14 year old rubber gets hard and cracks.

I wish someone made rubber bushings for adjustable panhard bars.

HioSSilver

iTrader: (8)

Clutch style diff. Just felt like the back of the car was moving arOund. It was wore out.

dws6

Panhard is probably a neg 10 degrees down toward the axle when suspension is compressed. Given 0 degrees is horizontal and positive would be up toward the body. Its nearly level.
I cut 2.5" off each side of the axle tubes and rewelded the flanges back on. put in the new bearings and seals and then ordered new shorter axles from Moser.
Only benefit is that I wanted a deep dish concave wheel. here is what it looks like now.

dws6

good point

I haven't had the time to climb back under the car to check things out so the plan so far is to double check tightness on everything AGAIN!, I don't specifically remember greasing the rear sway poly bushing at the rear mounting points on the axle tubes so I need to check and grease that. If it still doesn't work then I will remove the rear sway and try the factory unit. Next will be new control arm bushings but the issue only started after this set of mods. It was fine before that so I don't think LCA are the issue at this point

Thanks for the suggestions guys. It gives me some things to look for.
Let me know if you can think of anything else to look for.

libertyforall1776

iTrader: (2)

Phone UMI, I believe they do, but they are upon request...

I would skip the PHB and consider a Watts Link.

Guitar

iTrader: (9)

You really need to once again stop pimping that with absolutely no explanation for it whatsoever. A Watts link is NOT for everyone, especially for someone who just drives their car regularly and isn't a corner carver and usually prefers straight line or normal driving.

leadfoot4

iTrader: (1)

A couple of random things come to mind. I'm an old "circle tracker", and we used "stagger" in the rear tires to help the car to turn left. The rear axle was a spool, and the right rear tire is slightly larger that the left, so the car has a natural tendency to turn.

You say that your problem occurs during hard acceleration. Is there any chance that your differential is acting strangely, and locking up under full power, along with possibly a pair of mis-matched rear tires? Or, is there a chance that your ABS, or traction control, if you have it, is malfunctioning under full power, thinking it's seeing wheel spin, and trying to apply braking to one of your wheels?

Like I said, just a couple of random thoughts.....



Why? I've had poly bushings in my PHB since 1996 without any issues....

Coppertone

I would like a little more cushion in the rear. The polys don't give as much as I think they should.

z28bryan

iTrader: (7)

Poly or rod ends really don't have that much of an extreme effect on ride quality though compared to if they were on the LCAs. Unless you are turning really hard really fast all the time. When hitting bumps while normal driving, that is foward/backward. The LCA ends absorb a lot of those bumps.

It sounds like it's not a PHB issue in any case. That sounds level

sopes

Those are some nice looking wheels and tires ! just gonna throw it out there but with the wider setup could it just be the tires pulling into ruts ?

JD_AMG

DAMN that looks good.
Ok so when modifying the rear end are you sure everything was done precisely? Nothing is possibly bent or cracked? Was everything torqued down correctly when put back together?



If nothing else the watts link will eliminate any inside tire rubbing issue that the PHB could cause.

ChrisRZ28

I'll just add that when I had a adjustable poly/poly PHB with no wheel spacers, the poly would flex enough (under hard cornering) that the rear tires would rub on the insides. I've got 17x11, 50mm ZR1s. I had one of those spohn adjustable PHBs with the adjuster off center. I could never keep that thing adjusted right. The rear axle always seemed to readjust itself left or right (somehow). So I bought a rod/rod-ended PHB and started using 1/4" wheel spacers and haven't had any rubbing for years. My guess is if I used spacers with the poly/poly bar, the rubbing would have been reduced. I've been pretty happy with my rod-ended bar, it doesn't make noise and stays adjusted where I want it.

dws6

Ok so here is what I found tonight when I rolled under the car. Both poly bushing mounting the sway to the rear were dry. No grease so possible binding???
Also one of the sway bar end link bushings are missing again. Same one as last time. This is indicating to me a over tightened condition and when loaded its tearing and ejecting the bottom bushing. This is the secong time it happened where the bushing disapears. Has to be an overtightened issue. I have to get another replacement and try again.