996 exhaust rattle

[r8_1ndy]

Another problem on my car is that i seem to get a rattle on my right side exahaust. I've been told that it could be a baffle loose but to my inexperienced knowledge it seems like the exhaust mount is loose. Its got a fair bit worse now as everytime i drive it slowly using low revs, when i change gear, the instant i put down any power on the throttle the exhaust has a tinny rattle until it gets over 1200 rpm. What could this be??

[rob05]

My car sounds the same just on start up though,it could be any of the the things you have mentioned or the heat shield.On a 2.5 boxster i had, this rattled so much i just binned it,il have to check mine out too.

[gfreeman]

Crawl underneath and thump things with your hand it is either a broken/loose bracket, your heat shield or a loose baffle inside the silencer box.

Usually one or more silencers on ebay or get one from a breaker for about £100.

[r8_1ndy]

Do silencers get more throatier as they heat up or do i have a sports exhaust, because after a good thrash it gets a little deeper and throatier??

[DanH]

Exhaust sounds always changes once it warms up.

[Raven Flyer]

Lots of short journeys will cause a build up of moisture in the box. On a baffled box this won't make much difference, but it will make a big difference on a straight thru box (perf pipe and wool packing) as the water will increase the density of the packing material.

When the box heats up to over 100degC, the moisture will evaporate off and normal volume will be restored.

On the baffled box, the helmholst chambers will be specific volumes/lengths to invert the sound wave and cancel the noise out. If there is a lot of water in these parts of the box, the frequencies that are cancelled will change. Baffled boxes heat up very quickly as there is no packing to act as insulation.