I have all the components to put together a mousse can muffler. I am wondering what the purpouse is of the aluminum 6" pipe inside of the mousse can does, and if I can do away with.

I got the know how from this web site
[link=http://www.spadtothebone.com/SPAD/Mufflers/Irvine_1/irvine_1.html]Mousse Can Muffler[/link]
but it does not say as to what the purpouse is or if I can do with out.

thank you.

If you leave it out, you just have an ugly muffler. The way a mousse can muffler works is basically a folded tuned pipe, like an UltraThrust muffler. You might get a small gain without the inner tube just because of the larger volume, but not as much as if you built it per the plan.