"FLAPPING" SOUND FROM MY FLOWMASTERS

[nineFiveImpalaGuy]

OK here is the deal, i have a "flapping or fluttering" sound coming out my flowmaster exhaust. i was told that i need to get new plugs so i went on ahead and got a msd 6a ignition control ,msd coil ,ngk spark plugs, gatorback belt and march pulleys. I just got this done about 2 weeks ago and im still hearing this "fluttering" sound and its stating to piss me off. It still runs good and the gas mileage is excellent but im still hearin that sound.
Any body have an idea of what it is? HELP ME OUT PEOPLE!!!! :LS1LT1flag:

[Freedster]

First thing I'd look for is a loose hanger in the exhaust system. If your pipes are shaking just a little, they might be scraping something as they vibrate with engine RPM's to make a noise.

[nineFiveImpalaGuy]

Thanks man for the info. But i forgot to mention that it "flutters" while im in idle so could it still be a hanger if its in idle?

[Freedster]

Hmmmm.

Not sure without hearing it. I can't see how the plugs would have helped, so I'm sorry it didn't fix it, but I'm curious why someone thought that would fix the issue.

It could be the hanger, even at idle. It could also be a loose joint somewhere that the pipes are bolted up, or a blown/burnt gasket at one of the joints. An easy way to tell that is to get under the car at idle and listen for the exact source of the noise. If you don't have a mechanic's stethescope, it's not a bad idea to have one for things like this. If your flutter is coming from a joint, then you know.

It might also be you have a cracked catalyst in your convertor, and you're hearing the pieces rattle. Easy way to check for that is to tap on the system close to the convertor with a hammer, and see if it rattles inside the convertor.

Now, another thing that can cause a fluttering noise has to do with the dynamics of exhaust systems, and there's not much you can do about it. When exhaust exits the engine, it comes in pulses as the engine pushes it out during the exhaust stroke, this you probably know. The thing is, depending on one of about a zillion factors, those pressure waves can get into something like a muffler chamber and collide in all sorts of ways, changing their sound. That's something that muffler companies count on, and they tend to make systems that cause the pressure waves to resonate in "appealing" ways. Problem is, in your system, it might be that some factor is making the resonance sound like a flutter. It could be the curvature of your pipes, the diameter of some inside radius on your pipe around a curve, a hairline cracked catalyst in your convertor causing a disruption in the waves, the alignment of the planets, sunspots, you name it.

Another thing to consider, I guess.

Hope that helps!

- Freed

[nineFiveImpalaGuy]

Thanks alot guy! it was the hanger on my exhaust. I took it back to where i got it done and they took care of it, so it was the hanger thanks again man! peace :LS1LT1flag:

[Freedster]

w00t!

Score one for the Freedster!

:)