Okay well let me first elaborate what happened,maybe you could help me out better. Okay i have a 1993 trans am with an auto transmission. A week Ago i was lifting the car alot from the frame bars under the car not the plastic honey comb piece right next to it.The reason for that was because i was putting in my long tube headers.i would lift the car high from one side and then the other. So after installing, I took it to the exhaust shop and they did a shitty job.They kept the original y pipe,but cut a hole in it smaller than the diameter of the pipe in it and used some other piece of pipe and ran it to the other header.So after the install i immediatly noticed that as soon as I start to go of a stop it makes some noice kinda like if you had a loose hex socket in a metal tray and you shook it or like if the car was front wheel drive and the drive axels where going bad and poping. But the noice comes from under the drivers side and Ive taken a look at it,but see nothing wrong,what could it be?

 

It could be the header/y pipe where it goes under the drivers side frame rail. If it is this, its actually pretty common

 

You mean the sound that is making is common?and why would it do that cause of the shitty job they did?

 

Yeah its common. That doesnt make it right though. On LS1 cars its common after long tube installs for the header collector/y pipe connection to rattle on take offs because it is so close to the frame rail. You may want to look at that area first and see if its real close

 

Yeah because it only does that on take off,but i checked the collector and y pipe connection and its solid not loose or anything.

 

Its not the connection its because the motor torques when you take off and makes the pipe hit

 

You might want to check and make sure that your motor mount hasn't gone bad, allowing the motor to excessive rock under acceleration. This, in turn, would also cause the exhaust to hit the floor pan.

 

well the sound came all of a sudden so wouldnt it have done it prior to the lt's?

 

No the LTs change everything....lay down and look at the clearance of the drivers side pipe off the header..and where it goes under the front subframe I'd be willing to bet its damn close...you may even see where its been hitting.

Even guys that buy and install Offroad Y-pipes that go with the headers frequently have this problem. As said earlier...common yes...but that doesnt mean you cant fix it. Have a look and tell us what you see.

 

same problem here, except its on the passenger side of my car

 

I had the same problem after the header and 3" exhaust install. It was under my feet and I had just gotten the torque converter put in so I thought maybe some of those bolts had come loose. But it was the exhaust hitting the subframe right where it makes the turn towards the center of the car.

I jacked the car up and unbolted the exhaust then took a grinder to the lip of the brace and ground it down. It took a little while, maybe a couple of hours. Plus it's on the overhead so you gotta watch where those sparks are flying but after it was ground down I bolted the exhaust back on and haven't heard peep since. Problem solved. I'd bet a dollar to a dime that's what your'e hearing.

On a side note, be careful with the grinder under there. The fuel lines are run right next to where you have to grind (at least on an LT...can't speak for an LS). I know I don't have to spell it out but I will.....sparks + cut open fuel line = boom. Also wear some eye protection man. You only have one pair.

G/L with it.