windveilpete

I installed an american thunder flowmaster about two weeks ago, and now that it is getting broken in, the exhaust tone is just getting better and better - this is part of my problem - I would love to keep it. The problem is, at about 45 and 72 mph when the engine is under a load the damn things RATTLES and it isn't getting any better. I have gone under the car to see if anything was loose, and can not find anything. Think those goofy rubber band hangers might be the problem? The car never made any noise back there until after the muffler install - but it sounds like it could even be the license plate rattling (but i really doubt it, as the load on the motor seems to be creating or affecting the noise.

Question or two-

On the stock muffler, there is a counter weight or counter balance welded to the muffler... I know the flowmaster was designed for my car, but could the absence of this be causing the problem on the new "improved" model? I am thinking of taking off this hunk of *$%&% and taking it somewhere to have the balance put on it and see if it makes any difference. But if it needs one, why was it not in the directions from flowmaster to swap it over, or just made with one.

Is there somkething I could be missing here? The rear bumper is mighty flimsy, could something in the air pattern be causing it to flap around and is shaking the muffler?

Seriously, its disheartening to buy something that's supposed to be a great product from a reputable company, designed spcifically for your car, and when you put it on, it drives you nuts.

Any other ideas? Maybe I will sell this damn thing on ebay and buy the borla.

rygenstormlocke

Hmmm, odd one. All the ruber dampeners have been removed from my car long ago. It might help.

windveilpete

What did you use to attach the muffler to the brackets?

Rrruss

When I installed mine I noticed that the front rubber "hanger' did nothing.
In fact if anything it is pushing down on the muffler instead of holding it up.

What I did do was leave everything loose so I could push on the muffler and get it as far as possible on the exhaust pipe to insure a good connection, then cranked everything down tight.

I only have had it on a few days, and have not gone over 50 with it yet, but so far so good.

It may be worth loosening everything up, try "wiggling" the muffler around to see if you can find the noise, and make sure your nuffler is on the exhaust pipe as far as possible.

There is always the chance that one of the baffles in your muffler was never secured properly, but hopefully thats not the case.

Good luck with it !

blackfoot

i had your problem, this is what i did,and itfixed it!, remove all the hangars, and apply red liquid lock tightto each of the bolts., then re-install hangars... everything fixed!.turns out the bolt backs off a tick,and the washers rattle enugh to hear it through out the car

NickSezz

when i put my mrt on the mid pipe was hitting one of the bars that cross under the exhaust pipe and was hitting it making a nasty rattle...check that too

windveilpete

Blackfoot, you are exactly right. Ii had this problem, and today went under the car to find the clamps LOOSE.. Tightened them up and no more rattle. Thanks! Thanks to everyone for their input, I was just sure that something was really screwed up with the muffler.

Thanks again!

blackfoot

make sure you put lock tight on them bolts, they will come loose again in a couple of days... lol i kept a 13mm ratchet wrench in my car so i would tighten them when i would hear the rattle again, till i got smart and used lock tight