Ever since I installed the Magnaflow muffler on my 01 SS, it backfires like crazy during deceleration downshifts. (It's almost as bad as having the cut-out off.)

Is this normal? With the stock (I presume SLP) exhaust on it, it didn't backfire at all.

 

does it back fire or just pop, loudly??

 

Isn't a pop a backfire? Sounds like a shotgun blast really.

 

That sounds like there might be a hole somewhere. Check around your muffler, it might not be sealed all the way for some reason. My ex-bf had a hole in his exhaust and it would give out a huge bang. Scared the crap out of me everytime.

 

Yeah, I already checked for that... it does the same thing with the exhaust cut-outs off. (My old 98 Z28 did the same thing with an aftermarket cat back exhaust on it.) Might just be loud popping that I am hearing instead of a true backfire.

 

Hm, that seems kinda odd. I dunno much about exhausts just yet, I just know I've experienced a similar popping sound and it was because of a hole. That would kind of annoy me too much to keep it on...

 

some times its just the mufflers that do it, my bangs but its deep , sound good but i have a pretty much straight pipe. My pals gto did the same as you describe until we true dualed it. Its like at certain revs, about 1500-2200 on the deceleration it would do it. I think its to do with the whole flow of things and the nature of the muffler creating a sound wave at those rpms?

If there is no holes and all joints are good, then thats it. Easy option, no muffler but its loud then!!

 

My car dose the same thing (flowmaster 80) on decel and it's an A4. If I go WOT and let off quickly at high rpm it gives a LAF pop but it's not a back fire. IMO let it ride

 

sounds normal to me, just about every vehicle ive done exhaust to will pop under decel. the factory mufflers create such a restriction and sound deadening that it wont do that to the point that you can hear it. just listen to any LS motor with aftermarket exhaust, they all do it.

 

i don't think that's normal to be honest...my car doesn't pop at all