I feel the rear of the car squat and lift when shifting during accelleration/ IRS?---

[alwayscode390]

I just got my car a month and a half ago ... and for some reason I just started noticing this. Probably because I am more comfortable and shifting on harder accelleration now.

It is my FIRST Independant Rear Suspension hotrod , and I am wondering if I am just feeling the typical stuff for this setup.

When I give it spirited accelleration and shift, I feel the rear of the car lift and ALMOST feels like it goes to the left, then it squats and goes to the right ... making it feel like it will break loose at any moment during shifting.

Is this just normal since the torque goes to the right rear tire on accelleration , then lifts and FEELS like its moving to the left when its really just centering itself again upon a shift? The quicker I shift the less I feel this , but on regular shifting its almost sketchy feeling.

Its not the up and down I am worried about ... its the feeling of the rear going left to right that is making me question my suspension (worn shocks?)

Thanks ---

 

[DrumrBoy]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

Some is normal, it can also be made worse by uneven rear tire air pressures.

 

[alwayscode390]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

I checked them not long ago ... but I will start by checking there again.

The 345/25/20's really dont have much of a feeling when they get low since there is no sidewall ... lol

I'm probably being paranoid with a lot of this stuff, but everyone on the forums and everyone I meet at car shows POUNDS it in my head to be careful with these cars ... a lot of them get wrecked. I just want to make sure the car is in tip top shape --- ---

 

[DrumrBoy]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

I don't think there's an inherent jump-to-the-left (or right) effect of IRS; though someone more knowledgable can chime in. However, everything from tire pressure to alignment to condition of shocks can unbalance the rear under load. I'm not good enough to diagnose which one is your likely culprit...so I started with the easiest one to check (and fix)! Good luck sorting it out and learn the car well before really whooping on it - its less forgiving than most muscle cars.

 

[latamud]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

I have an IRS under my 66 Mustang, had a similar issue, my rear coils were adjusted to different ride heights. This caused the weight of the car being supported by one spring at rest. When I accelerated the rear would squat and then engage the coil on the other side, but at a different rate. Until I figured it out the car drove like a table that had one short leg. I imagine you're running stock non adjustable coil overs. Do you have a broken sway bar end link? I think that could also give the off balance symptom you are getting.

 

[Voodoo Rob]

How many miles on the car? Possibly have one leaking or weak shock causing unbalanced ride. Check all bushings, links and shocks. Also check the rear end mounts, etc. My guess is suspension related.

 

[alwayscode390]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

I think you guys nailed it ... I keep thinking the drivers side sits lower on the rear , but told myself it was the parking lot angle when I look at it ... I am starting to think I have a sagging coil (or shock) on the drivers side (Eibach lowering springs with stock shocks).

When the car was in the air last , the sway bar end links looked squished and rotted ... but the mechanic said they sometimes LOOK that way but are good underneath the weathered rubber.

The car has 22k miles ... a 2001 GTS ... thanks guys.

Im guessing it may be time to upgrade to adjustable coil overs in the near future. ---

 

[alwayscode390]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

LOL you guys are going to laugh too.

I just went out and my Drivers Rear tire was DEAD flat ... they are new tires.

My Passenger Front was low a week ago, but is holding air now ... and all the other tires were fine.

This either means:

1. My three peice HRE wheels are leaking (is that a problem with multi-peice wheels?) or
2. Someone is messing with me and my car.

This also took care of the squeaking rubber sound I was hearing ... thanks for the help guys!!! ---

 

[Jack B]

Re: I feel the rear of the car squat and lift when shifting during accelleration/ IRS

I hope all turns out well - a little insight, if the car lifts too quickly in the rear that means the right rear shock has too soft of a rebound. If it then squats that indicates the compression is too soft. It could be a bad shock, you could also adjust them, it is a single adjustment on the oem shock.