I had recently installed a DC Sport 4-2-1 header on my car. Since then, I have been getting this rather annoying "rattle". It kind of sounds similiar to that of gears grinding. It primarily occurs anywhere over 1500 RPM and you can also hear it in neutral giving it some pretty good throttle. But over a certain RPM, the noise dissapears until coming back down the RPM curve.

The install went smoothly, but I searched the forums and came across threads about how some of the "exhaust heat shields" can come loose due to rusted bolts & what not. From what I know, the only exhaust heat shield I knew of was that over the factory exhaust manifold.

Could one of these heat shields have come loose due to the DC Sport install?
During an aftermarket header install, what exhaust shields might come loose most likely?

Later today, I'll be getting under the car to find out what exactly is causing the racket, but before then I'd like to have some input on the situation.

Also, when I removed the factory downpipe, there was no gasket between the flanges for the downpipe and the catylitic converter; just a bunch of RTV sealant (must have been removed previously). I've looked around and couldn't find where I could purchase a replacement without buying an aftermarket high-flow cat. Does anyone sell the gaskets seperately?

I have the same problem with my headers , and I have am running a high flow cat, and a CAI all new but there is a strange rattle around the header at about 2.5k rpm, I think its becasue they havnt been "broken in" yet.

-Keith

'92 BMW 325i - 3.91 LSD....Cold air intake....M52 headers.....Track pipe....Remus back....Fan Delete....UUC short throw...M3 Clutch Flywheel & Drive Shaft...Tien Coil overs

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Make sure it isnt an exhaust leak. If you can, turn car on and feel if any exhaust is getting out at where the cat and downpipe meet. I just installed headers over the weekend and I have a exhaust leak there now.

2002 WRX
Eclipse RS-T..sold

Did you replace the Downpipe as well, I know on my old sebring with the 420a the heat shield on the downpipe would rattle until about 4000 and stop. Don't know if this helps but thought I would throw my two cents in.

mine exhaust is rattling too . i found out where it is .its in the back the exhaust rattles against the spare tire well .

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I had that rattle before and after my headers I was told that its the cat a loose mesh shield inside it. I have never seen the inside of my cat so im not sure. Keep us up to date with this so I can fix mine too

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I had a rattle like that at about 2k rpms. The downpipe has a support bracket towards the front by the lower water pipe that I had forgotten to put bolts in. Fixed my problem.

Tony

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