Exhaust is making a fluttering sound?

[MrWray]

when i first modified my exhaust " resonator delete,replaced with straight pipe, and flowmaster super 10 mufflers" i pulled up to a stoplight beside another vehicle. when the light turned green i noticed a fluttering sound coming from the exhaust "sound was bouncing of the other vehicle". i thought that there was an exhaust leak somewhere so i turned around and went back to the shop. they fixed a couple of small pin leaks, said all was good, and i was on my way again. well i still heard it, it sounds good at start up and WOT, but when taking off from a stop, the best way that i can describe it is a light fluttering sound and doesnt have the deeper rumble that i should be expecting. what is causing this?

[Missile Man]

Originally Posted by MrWray

when i first modified my exhaust " resonator delete,replaced with straight pipe, and flowmaster super 10 mufflers" i pulled up to a stoplight beside another vehicle. when the light turned green i noticed a fluttering sound coming from the exhaust "sound was bouncing of the other vehicle". i thought that there was an exhaust leak somewhere so i turned around and went back to the shop. they fixed a couple of small pin leaks, said all was good, and i was on my way again. well i still heard it, it sounds good at start up and WOT, but when taking off from a stop, the best way that i can describe it is a light fluttering sound and doesnt have the deeper rumble that i should be expecting. what is causing this?

Hey MrWray,

It sounds like an exhaust leak by your description. I just had an X-Pipe installed yesterday and it doesn't make that sound. The guy who installed it started the car on the rack and used a stethoscope (kinda like what doctors use) up and down the exhaust to listen for leaks. Did they do this after your install? Hope you get it figured out, my try a different shop as a second opinion.

[LS3 SS]

Originally Posted by MrWray

when i first modified my exhaust " resonator delete,replaced with straight pipe, and flowmaster super 10 mufflers" i pulled up to a stoplight beside another vehicle. when the light turned green i noticed a fluttering sound coming from the exhaust "sound was bouncing of the other vehicle". i thought that there was an exhaust leak somewhere so i turned around and went back to the shop. they fixed a couple of small pin leaks, said all was good, and i was on my way again. well i still heard it, it sounds good at start up and WOT, but when taking off from a stop, the best way that i can describe it is a light fluttering sound and doesnt have the deeper rumble that i should be expecting. what is causing this?

Is it a Raspy sounding noise coming from the rear of the car? If so, that's normal.

[MrWray]

Originally Posted by LS3 SS

Is it a Raspy sounding noise coming from the rear of the car? If so, that's normal.

not raspy, my best description would be like a weak fluttering sound, maybe like a ragged out car that has lost some compression. ive had flowmaster installed on other vehicles and have never heard it from them. i just traded a 2006 dodge charger R/T that i had super 10s installed on and it didnt sound like that.its just one of those sounds that you know isnt right

[2SS45th]

Try this: have someone start the car for you, then turn it off when you are outside of it. If you hear a flutter on shut down, it's a leak. Sounds like a leak, but that's an easy test.

[LS3 SS]

Originally Posted by MrWray

not raspy, my best description would be like a weak fluttering sound, maybe like a ragged out car that has lost some compression. ive had flowmaster installed on other vehicles and have never heard it from them. i just traded a 2006 dodge charger R/T that i had super 10s installed on and it didnt sound like that.its just one of those sounds that you know isnt right

Go on youtube and listen to some 5th Gens with aftermarket exhaust. I'm pretty sure that sound you are talking about is the normal "fluttering/raspy" sound that these cars make with almost any combination of exhaust setup. I'm sure there are a few setups that can get rid of that sound, but I've even heard it on Corvettes. I hear it on my car all the time, but only when I rev the car up, or let out of a gear at a higher RPM.

[MrWray]

Originally Posted by Missile Man

Hey MrWray,

It sounds like an exhaust leak by your description. I just had an X-Pipe installed yesterday and it doesn't make that sound. The guy who installed it started the car on the rack and used a stethoscope (kinda like what doctors use) up and down the exhaust to listen for leaks. Did they do this after your install? Hope you get it figured out, my try a different shop as a second opinion.

im thinking leak too, and i even even asked them to double check and they said tht it was all good. you dont notice it when you stand behind it when its started, and you cant hear it at WOT, but its very noticable when your beside another vehicle "sound bouncing off" and when you take off from a stop.

[MrWray]

the only thing that i noticed that they did was....

the inlet and outlet of the super 10s are 2.5" and the exhaust pipe for the camaro is 2 1/4", and they cut small rings from 2 1/4" pipe and placed inside the edge of the inlet/outlet of the mufflers and tach welded them into place. i asked them why they were doing that and they said it was too fill the small gap between the inlet/outlet and the exhaust pipe since they were different size.

[Missile Man]

Originally Posted by MrWray

the only thing that i noticed that they did was....

the inlet and outlet of the super 10s are 2.5" and the exhaust pipe for the camaro is 2 1/4", and they cut small rings from 2 1/4" pipe and placed inside the edge of the inlet/outlet of the mufflers and tach welded them into place. i asked them why they were doing that and they said it was too fill the small gap between the inlet/outlet and the exhaust pipe since they were different size.

The shop I went to expanded the tips of the pipes that fit over the stock pipes and and over the X-pipe, all one piece. How they did yours sound a bit strange but hard to determine without having seen the process.

[1sikRS]

The pipes are 2.5 on the stock exhaust they should of only had to expand the inlet of the muffler most importantly make sure they used the inlet and not the out let its clearly stamped on the muffler case but the mistake can still be made

[MrWray]

Originally Posted by 1sikRS

The pipes are 2.5 on the stock exhaust they should of only had to expand the inlet of the muffler most importantly make sure they used the inlet and not the out let its clearly stamped on the muffler case but the mistake can still be made

i wouldnt say that they were expansions, the rings that they cut went "inside" the muffler flush with the edge. i dont know what the hell it is,all i know is that it doesnt sound right to me. ive only had them on there a couple of months, the only thing i know to do is take it back to the shop,let them hear it and see if they can remedy it, then if they dont figure it out, replace the mufflers with something different.

[The 2010 Sin]

I heard a fluttering sound too with my flowmaster catback when cruising. not with my new ZL1 catback tho.

[MrWray]

i was off today and bored so i went to the muffler shop and had one of the guys listen to the car. he wasnt any help to say the least. i start the car while he is behind it,revved it a little bit and let him listen too it. he tells me that he can hear it and it reminds him of the sound of a dead cylinder,then he says that its probably just the sound of the super 10s. WTF? so flowmaster super 10s are supposed to sound like a car with a dead cylinder? its just hard for me to believe that they are supposed to sound like that....i may be wrong though,ugh!

i hate not having a solution for something, could it be the AFM causing it? is AFM activated at idle too? i also wonder if headers will eliminate it?