i been driving it around alot with the muffler (magnaflow Dual HighFlow) and i was wondering do mufflers have to break in or....what becuz i actually feel more idk

You're seeing/feeling things. A muffler is simply a metal can with metal fins inside it, unless you buy a design that has packing in it. Even if you burn the packing out it won't give you "noticeable" power, just make your car sound like ***.

Try to use real sentences, it takes a fraction of a second more and goes a long way to prevent yourself from looking like a moron.

nope mufflers do not have to break in

however, tone does change... noticed by both me and bonnememn... on our flowmaster 80 series

Might want to have it checked.
Sounds like the muffler bearings may be getting ready to go!!!!!!

LMAO!! It does! Better get that in to an authorized GM Dealer!

Haro is right though, there is something like a break-in.. but more of the sound does change with new mufflers. I noticed it on my mom'* car too. Even though that is a factory muffler.

I'm not sure if haro'* got louder or softer, but me mum'* got softer.


-justin

As the metal heat cycles it expands and contracts, this softens it somewhat (not much) and it gets into a groove if you will. It also might get some buildup, which can change the tone.

If you have a glass packed muffer, or one with a lot of baffles/chambers they can change more.

Right, but regardless he will not see a noticeable increase in power.