dirtgar

Just installed headers and cats, and when I step on the gas I feel that its definitely faster, but when I have I had the ASR on could that cause the rear to shake and make weird sounds??? I sounds like the ASR is kicking in and trying to fight wheel spin. Could I break something? Should I only step on it with the ASR off?? Not to sound dumb. Help.

Injuneer

Does the "LOW TRAC" light come on when you experience the problem?

Turn the ASR off using the switch on the dash, and see if it makes any difference.

dirtgar

Yes, and I noticed that when I turn the ASR off it shakes and rumbles less. I also noticed that it feels like it coming from under and in back of the driver seat. I had some friends check it out and they think that the shop that installed my headers and Y pipe probably left something lose or some exhaust part is loose. ???

Zee man

Probably vibrating against the floor boards or a cross member when you get on it.

dirtgar

I did notice that the cross member piece that went under neath the original Y-Pipe is missing, when I called the shop they said that when you do these mods the new wider Y-pipe doesn't allow enough space to bolt the piece back in. I wonder if that is whats causing the car to rumble under hard acceleration.

Injuneer

No, that's just a brace for the chassis sheet metal. It should be reinstalled. A "wider" Y-pipe should not cause a problem.... never heard that before. It will also retain the driveshaft in the event the driveshaft breaks. Even if there is a problem, all they need to do is space the sheet metal brace off the floor using washers. It wouldn't cause a "rumble" though.

What headers were installed? Since you mention Y-pipe, what cat-back are you running?

I wonder if they screwed up the torque arm, or the torque arm front mount bushing is damaged, or if the trans mount is broken.

dirtgar

the headers are SLP and I also purchased the Y-pipe with the high flow cats, the car has a borla cat back exhaust. You mentioned that they might have damaged a torque arm, can I check it just by moving it with my hand or would I have to remove it to inspect it?

Injuneer

With normal weight on the ground, the torque arm should not move. It's job is to prevent the rear axle pinion shaft from rotating upward when the car accelerates, and rotating downwards when you brake. If it got loose, it would make a racket.

I don't know about the LS1 exhaust, but with the LT1 setup, one of the bolts that held the stock cat bracket in place also held the torque arm front bracket in place.

The front of the torque arm fits into a bracket, with a rubber bushing in it. The bracket is mounted to the tailshaft housing of the transmission. If the bushing is loose or the bracket is loose, you could feel the rear axle jerking and rattling. Since the tailshaft housing of the trans is sitting on the transmission mount, if that mount is broken, the torque arm and the trans will be moving up and down when you accelerate and brake. Usually you will hear a thump when the trans hits the floor of the car.