Originally posted by jrpatterson
do a search on here a couple people have modified the stock exhaust and have liked the sound achieved by this.
One of those would be me.
I'm sure the end-can manufacturers put a lot of time and effort into tuning their products to get a particular sound or even "feel," but at the end of the day, the cans produce similar HP gains resulting from their being open straight-through and improving the flow of exhaust gasses from the engine.
Since the HP gains are the same, then it boils down to sound and quality. You can "tune" the sound of your exhaust note with the thickness of the sheet metal that will be rolled into an internal sleeve: the thicker the metal, the deeper the sound. I got the thickest metal they could find, had it perforated in the same way aftermarket cans are, and it now produces an exhaust now that's deep and can be felt rather than heard thru the house. It crackles and pops on the over-run too, like aftermarket, and has a solid baritone scream at speed.
Yup, I got +2-3 HP with the modification.
Just make sure that when they roll the sleeve, the side on which they drilled is the inside of the tube so that the inside is smooth. If the inside is rough from protrusions in the metal, the gas flow will not be as smooth either.
Gutting the internals takes some effort, as the 4 chambers making up the stock can are very tightly wedged in. You'll have to destroy it to take it out, so there's nothing to restore if you were intending to keep the internals.
I didn't drill out the end caps or anything, just took out the stock internals wholesale.
Best part is it cost me less than a hundred dollars, while giving me recurring amusement when I start up and other bikers jump because it looked stock [^]. And when I get tired of the note, I'll just replace it with a different gauge metal.
Hope that helps, for those who want to save a few bucks ...