NakedDave

I believe it's the X pipe at the end of the tunnel where it goes to connect to the muffler pipes (OEM mufflers) - everything is lined up and the rattle is only when cold.

Anyone seen this before I jack the car up and take another look? thanks in advance

LBRc7

I had a bad rattle after mid lengths and x pipe install. I had a clamp touching the center plate. I'm betting something is just rubbing the body when cold and after it warms up the pipes move away enough to not hear it anymore.

FYREANT

Yup. And also had my Xpipe touching my trans. Had to pry it out of the way and hold it that way while tightening clamps.

Mr. Smith

I agree with the above statements.... I had a bolt touching the center plate causing a rattle. Get under there with a flashlight and look around carefully, you'll find the source. What headers? Kooks? American Racing? I have Kooks and they fit perfectly. My shop just didn't do a careful check after install otherwise they would've noticed the bolt touching that metal center plate. It annoyed the hell out of me for a few weeks... all quiet now though

Rdubfalco

Exactly this,

Providing the manufacturer of the header would be helpful. I installed kooks long tubes and catless x-pipe; most likely what you're hearing is the clamp bolt side vibrating against the belly pan. Cut that sucker down a few threads with a grinding wheel (careful as to not distort threads) and be done.

NakedDave

Thanks guys! Need to get off my a$$ and check, but it sounds easy enough, cheers.

NakedDave

American Racing by the way, dropped the center plate, and it was one of the clamp bolts, turned it sideways a touch and it's perfect now.

Thanks for the tips gents!

rickster1823

Bumping this.

I installed 1 7/8" Kooks with Catted X pipe and i noticed my Passenger cat was touching the plate. I just took my Hammer and hit it a few times since adding washers did not have enough clearance. That only solved part of the rattle.

I noticed that the clamps that connect from the X pipe to the Header are extremely big. WIth a slight tilt on the bolt, the bolt will hit the tunnel plate and if you set the bolt straight up and facing the tunnel frame when you fire up your car you will still have the rattle inside the cabin because the clamps rest on the frame and the vibration of the exhaust pipes just transfer all over the car.

I wanted to ask anyone here if by chance they have modified their tunnel plate to have clearance for the exhaust clamps? Perhaps maybe cut the plate so that there is room for the clamp rest the bolt parallel to the ground?

FYREANT

do not cut the tunnel plate. The tunnel plate is actually structural and provides chassis rigidity for the body of the car. Thats why there are so many bolts holding it on there. Find a way to adjust or modify the x-pipe.

JMII

So. Many. Bolts.

When I did my x-pipe, like an idiot I didn't check and had a small leak, so they all had to come off... again - so lesson learned: don't button up that plate until your 110% sure

NakedDave

Flip or adjust the clamps; they don’t have to face in or out, just be in there “square” and tight.

rickster1823

Not possible. There is no other way the clamps can fit.