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hole in muffler?

Posted: Sat May 07, 2005 7:52 pm
by usdthrone23
think it would give it any more power or just noise ? haha

Posted: Sat May 07, 2005 9:52 pm
by vette76
depends where it is. noiseguy would be the one to talk to about this.

Posted: Sun May 08, 2005 1:33 am
by usdthrone23
some one hook me up with info .... were to drill the hole at? ive already filed my intake im grinding some metal off for a custom exaust and im drilling a hole somewere in my muffler once i know were :)

Posted: Sun May 08, 2005 4:36 am
by noiseguy
According to the tech post that I found, the author recommended drilling 4 1/4" holes spaced around the tailpipe outlet. You'll need a longer bit than most have on the shelf; you need to drill 1/2 way through the exhaust. You should go though 3 walls, including the outer. It's recommended that you bump the main jet up to a #70 for this. Read "plug chop" in tech docs here. You don't want the scooter to lean out.

Turns out the Spree muffler is made up of a absorber section (first 2/3) and a baffle section (last 1/3). I finally split one with a bandsaw, out of curiosity. There are 3 baffle chambers. By drilling these out you're defeating the baffled section. You could technically do the same thing by sawing off the back 4" of muffler, which is what I'm trying now with a spare... I'll let you know how it turns out. I'm waiting for some new jets to show up here first.

Posted: Sun May 08, 2005 9:56 am
by burnt_toast
would the holes be placed like this?:

back view of muffler:
/``````\
..H....H..|
.....O.....|
..H....H..|
\______/

where H is the hole, and O is the muffler tip.

Posted: Mon May 09, 2005 9:24 am
by noiseguy
Yes, exactly like that. Drilling from the back to the front of the muffler.

Posted: Tue May 10, 2005 12:06 am
by burnt_toast
so do u know yet if u get any decent power/sound gain? let us know.