hole in muffler?

usdthrone23 · Post by **usdthrone23** » Sat May 07, 2005 7:52 pm

think it would give it any more power or just noise ? haha

vette76 · Post by **vette76** » Sat May 07, 2005 9:52 pm

depends where it is. noiseguy would be the one to talk to about this.

usdthrone23 · Post by **usdthrone23** » Sun May 08, 2005 1:33 am

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

Post by **noiseguy** » Sun May 08, 2005 4:36 am

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.

burnt_toast · Post by **burnt_toast** » Sun May 08, 2005 9:56 am

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.

Post by **noiseguy** » Mon May 09, 2005 9:24 am

Yes, exactly like that. Drilling from the back to the front of the muffler.

burnt_toast · Post by **burnt_toast** » Tue May 10, 2005 12:06 am

so do u know yet if u get any decent power/sound gain? let us know.