why headers make exhaust not as loud

[2Good_86]

hey guys i have a 89 fullsize chevy blazer V8 350 TBI. And had replaced the stock exhaust with flowmaster 40 series and cut the cat off...It sounded nice and loud.. so i figured i put headers on it instead of orginal exhaust manifolds...Bought Dynomax ceramic long tube headers for it and now the exhaust doesnt sound near as loud...Should i go true dual exhaust..why did that happen? any advise is welcome.

[Timbo1969]

It should have gotten a little louder..hmmmm I don't know what to tell ya.. ditch the flowmaster and do duals I guess.. then it will be extremely loud..:devil:

[TigerEyz3]

hey guys i have a 89 fullsize chevy blazer V8 350 TBI. And had replaced the stock exhaust with flowmaster 40 series and cut the cat off...It sounded nice and loud.. so i figured i put headers on it instead of orginal exhaust manifolds...Bought Dynomax ceramic long tube headers for it and now the exhaust doesnt sound near as loud...Should i go true dual exhaust..why did that happen? any advise is welcome.
Just one question... (not that it is important to address yoru statement/question) Are you talking about the in-cab volume or the volume at the tailpipe?

As Timbo stated, I had been told that adding headers would make the exhaust louder. Theoretically, this makes sense because the headers are thinner than the cast iron manifolds - which inherently muffle some of the sound. I observed just the opposite, adding headers mellowed out the exhaust just a bit.

My best estimation is that the headers smoothed out the exhaust flow (that's what happened on mine, too), therefore decreasing the "fight" in the exhaust flow and reducing the note you were used to hearing with the manifolds.

More intellectually speaking, I'm thinking that the headers are arresting some of the sound by enhancing the exhaust pulse flow.

[AnthonyZ71]

when i put my thorleys on my 00 5.7, it quieted the exhaust quite a bit, almost stock like. i gutted my cats and the sound came back... but it surprised me when it quieted down so much with the headers.