I put on a Flowmaster on about a week ago. I've heard they have a break in time. Will it get louder? Its dumped by the way. I don't drive it but maybe 4 days out of the week. How long will it take?

 

Take it on a nice long highway drive. The heat generated will expedite it.

 

I've never heard of a break in time for a muffler.There are no moving parts,nothing has to seat,I don't know about break in time.I just replaced my 40 FM's w/ the 50 Delta flow.I ran the 40's on my truck for three years,my truck is my daily driver.Over time I really couldn't tell if there was a difference in sound as as I drove my truck every day.When the mechanic @ the muffler shop cut the old 40's off,broken rusted pieces fell all over the ground out of the muffler.I'm sure over time w/ wear and tear the sound of your mufflers will change,they'll get louder.Hope this helped .

 

I'm not exactly sure how the chambered mufflers need a breakin time either, but its sorta true they do get louder after awhile, atleast 1,000 miles I would say it would be broken in good.