Can a sports exhaust get louder over time?

[softinthehead]

I have a Janspeed sports exhaust on my 968, supplied 3-4 years ago by Promax. At the time I thought it was pretty much perfect - nice growl under hard acceleration but not too excessive when pootling around.

Lately Ive been getting the most uncomfortable feeling, especially when driving through town, that I/m in a souped up Saxo with little blue lights under the chassis. People seem to be staring more. The resonance in the cabin at low revs is really quite uncomfortable and if I push the car hard the noise is, well, not subtle. If i cant be bothered to change down and just stay in third, then start to accelerate from low revs, its like being at a Led Zep live act.

I thought it was just me, but my family and friends report that they think its got louder too. Apparently I can be heard from miles away.

Ive looked over the exhaust - nothing is loose, there's no rattling noise of loose baffles etc. So my question is, can an exhaust get louder over time and if so, what possible causes and how to correct it?

[softinthehead]

R5GTTgaz said:

Baffles can get coked up so they become a bit less efficient.

so how long does this coking process take? had the exhaust just under 3 yrs, no track days, infact pretty modest demands on the car, but its a 14yr old engine. so would this happen in that time?

i take the point made later about fine wine. statistically its reckoned that about 1 in 6 wines kept for more than 5 years has a degree of corkage (though many of these will still be ok to drink) - so age doesnt necessarily confer benefits!