Pointless question, but anyway: does an exhaust system's sound change as it ages? And if so - what is the technical reason that this occurs?

I'm not talking about cold engine vs. warm engine. The question is related to miles (like thousands of miles)....or heat cycles.

Thoughts?

 

the cat will start to restrict flow as it ages and dies, that will reduce noise

 

i developed less rasp as my XYZ pipe with resonator got "broken in"... i dont really have an explanation why this happened, but i believe it has something to do with the material inside the resonator getting packed in or something like that?

 

Depending on muffler design and internal construction (materials used to "pack the muffler"), sound can change over time.

Some muffler use cubes, some use fiberglass-like strands, etc. As this material heat cycles and ages, the sound of the exhaust can change.

In addition, as your 350z's ecu "adapts" to the increase in flow of the exhaust, the ecu may alter AF ratios, and this richening or leaning out may change the sound of the exhaust as well.