I am repacking my can with rockwool.

Could anyone please tell me how dense the packing needs to be.
My main aim is to reduce the dbs.

Not very, you dont want to compress it from its original form too much otherwise the gasses will be unable to pass through the fibres and so you end up with less sound absorbtion.

Rockwool isn't ideal as a long term solution though as in my experience (on a friends race car) it gets blown out quite quickly so either buy the proper stuff or be prepared to repack it quite often.

Chris

the rock wool i used caught fire and went hard and ratteld.

Thanks for your replies.

Whats the best packing to use?

Barry

Exhaust Wadding!

Most of the motorsport places sell it, Demon Tweeks / Merlin etc Id think, and maybe somewhere like Car Builder Solutions (which will probably be cheaper if they do)

http://www.nfauto.co.uk/silencer_wadding.htm

Hi Is this the stuff that looks like white cotton wool ???

If it is i think the stuff is called caowool,
you could probably get it much cheaper from an industrial heating firm,
places that do boilers ?

gezer

sorry, wrong spelling should be Kaowool,

gezer

The glasspack I got for my old bike exhaust said to stuff the silencer as tightly as possible for maximum silencing efficiency. I used Rockwool after that and found it to work just as well and last as long if I crammed it in to the same degree.

We've done some experimentation on our Radical clubsport as its usually close to the noise limits. Best combo we found was to wrap about a 1/2 inch of wire wool around the perforated tube. Then wrap the eGlass matting that Merlin sell around this. Don't pack it though just needs to be snug or the noise absorbtion goes down.

The basalt does resist higher temps just in case the eglass is melting too quickly. As others have said though it tends to blow out quicker.

Personally I'd like to try some fins or partitions on the perforated tube on the packing side. This is because quite often the packing gets blown towards the exit end of the silencer.