I've got a Chromerzone 7-style side exhaust - and I've been getting more and more sensitive to how noisy it is. It only just passed the SVA (by 1 or 2dB) and it's got noisier since then. I thought that the stuffing had gone, but everytime I've looked inside the 'ole it's looked OK. As these silencers are very hard to restuff I've left it alone (you have to pull the inner tube out a bit, and push the stuffing through the gap.)

I've finally got fed up with it and have slit it all the way round so that it can be re-packed the conventional way - and I think I've found out the reason why it wasn't working very well. The packing had been rammed in so hard that it was near-enough solid, so there was nowhere for the gasses to get in amongst the fibres to allow sound pulses to get absorbed. I had a hard job levering the wadding out with a long screwdriver!

Now I have to make a sleeve to allow the two parts to be re-joined, then I can repack. I shall probably use rockwool, maybe with some stainless wire wool underneath, but I'd like some guidance about how firm the packing should be: loose, snug, or f-tight (as it was originally ).

cheers,
David

I think snug is best, as you stated too tight is useless, too loose doesn't give enough absorbtion.