2FAST7S

I was coming back from getting my car tuned on Friday. About 14 pulls on the dyno. Anyways, on the way back home i got held up at the tolls. My boys, who cut ahead and got through the tolls quick hit me up on the 2 way to let me know there was no cops. Naturally, with the car tuned and running good afrs, i got on it...took 3rd all the way up to rev limiter, shift to 4th and keep it right around 5500rpms for a few miles till i had to slow down cause traffic got a bit too heavy...once i cought up to them we were going about 60 or so, didnt hear anything funny. Now, when i got home and got out of the car thats when i noticed the brand new rattling sound coming from inside the catback...its weird but i'm guessing i burned an broke loose something inside it, i dont know! Has anyone had something like that happen??? My catback is the old school HKS super dragger from the mid 90s when i bought the car in 97...It doesnt seem to make much of a difference except for the "new rattling".

Brent 94

iTrader: (1)

do you have a high-flo cat? If you do than the brick inside of the catalytic converter is blown(loose or in piece's) I've gone through 2 high-flo cats and they both had a different rattle sound to them. My first, only rattled when on the gas but i couldn't hear anything from inside the car. A friend pointed it out to me. My second would rattle at idle and seem to get worse the faster i'd go. If you don't have a cat than i don't know what else it could be.

BigIslandSevens

iTrader: (4)

check the exhaust heat shielding around the catback. Mine contacted the can after the last install. Must have hit it and bent it into the wrong place. I just reached under and re-bent the shield so there was no more rattle.

Haveing it strapped down on thedyno may have tweaked the shield a little. Depending on how the straps were run. Just a idea to check. As i had a "new" rattle as well when the can was replaced.

If you think it is the baffleing inside the muffler, you could take a long stick or pipe and stick it in to see if contacting the components inside stops the rattle. If it does,.. Then you need to either live with it or replace the catback.

The cat going bad is also a good place to check. That you could "probably" tap with a hammer or screwdriver and see if you get a ratle from it. Saves having to remove it to check. and if it is loose enough to make noise it should show itself.

2FAST7S

no cat...mid pipe. Its raining otherwise i would have jacked it up and taken a quick look under there. I think its the baffling inside the muffler itself...it sound like its comming from inside not outside.
I've had experience with a clogged cat and its nothing like that...theres good flow its just that funny kinda screeching rattle....
cant hear it inside the car so i dont really care but the fact that its there is anoying!!
thanx for the input though!