Exhausts

TimD · tinkerer Joined: 04 Mar 2002 Posts: 456

I have been searching through old posts on exhausts, i read often about 'straight through' systems. Can someone tell me exactly what this means?
cheers

Badger · tinkerer Joined: 13 Feb 2002 Posts: 155

this means the muffler is composed of a straight pipe throught the middle with holes in it surrounded by the body of the muffler. the holes lead into the body of the muffler, which is filled with packing (steel wool, fibreglass). the sound waves can expand into the packing and are deadened in this way. theoretically this gives a muffler with the flow of straight pipe, but quieter. in practice, the holes cause turbulence, reducing flow slightly, depending on how they are cut. really only needed for race cars, very loud but low restriction.