The "Ten Dollar, 96db Muffler"....

or, how I managed to quiet the beast without going broke!!

For my Viper with the Webra, I wanted to start working on noise issues.  The KS canister was pretty quiet, but it's back pressure was creating a bit more effects than I wanted to have, particularly at mid-throttle.

When you have a motor that turns an APC 17 x 12 Std at nearly 8000 rpm, you better have a good midrange, and transition...so...I started looking around in Wal Mart for some appropriate "cans"....

By the way, this makes a LIGHT assembled unit.  My three prototypes weighed 5.2, 5.4, 5.7, respectively, and simply reflect different amounts of brazing, painting, tube lengths, etc.

RECIPE - To do this muffler, you'll need;

To prepare, you have to decide WHICH aromas of Glade you'd like to fill the fresh outdoors with, as the FIRST step is venting the contents outside....I do this by holding the can firmly pointed away from me, grabbing the valve stub metal housing on the top of the can with my large diagonal cutters or long-nose pliers.  Twist, and yank, and the small metal cap will pop open, venting all the good smell from inside - THIS HAPPENS VERY RAPIDLY!!!  BE prepared!!!   You MUST have a good grip on things to do this....

Next, remove the labels.  Clean the outside of the cans...Using your Dremel cutoff wheel, cut the whole top off of ONE can, just under the edge of the top seam...it cuts like butter.  After you have this removed, clean the inside of this can thoroughly, then mark a hole on the outside, about 1 - 1 1/2" forward from the closed end.  

Cut a piece of Brass tubing, about 3" long, on a 45 degree angle.  Hold it with the angle against the can where you marked it, and scribe or marker an outline on the can surface.  Using a "side cutter" bit in the Dremel,  cut an opening smaller than this scribe mark, about 1/16" in.  This will permit enough material to be bent OUTWARD from the hole, making a friction-fit mounting area for the angled brass tubing.  When you have the opening made, keep test fitting the brass tube with the ANGLED end going into the opening, and it should just barely protrude INSIDE the can.

When satisfied with the fit, use the edge of the Dremel cutoff wheel to roughen/clean the brass tubing, and the 'flange' you've made in the can opening.  Insert the tube, and be sure it will STAY under friction fit, with very few gaps.  Heat the joint appropriately, then braze the tube to the can.  Clean it all up nicely, roughen the TOP edge of the can where you cutoff the seam/cap, about 1/8" down the curved edge.  This becomes the brazing contact area to the seam of the FRONT half of the muffler, so clean it well!!

FRONT ASSY - This is a bit of a challenge.  First, decide how many holes go in the BOTTOM of the can you have left over.  This is the "baffle", and is vitally important to control the tone and noise of the muffler.  Drill, then smooth, these holes around the outside bottom edge of the can. 

I built three, two using 5/16 x 6 holes, the other 1/4 x 8 holes...slight differences...It's only really important that you have the holes toward the outside, and NOT inline with the inlet tube you'll braze next.

The inlet tube needs to go inside the forward can about half way.  Not too critical, but moving it's distance from the baffle COULD have a 'tuning' effect.  Decide before you braze it in place.  Using your side-cutting rotary bit in the Dremel, cut around the stub in the top of the can JUST enough to permit you to cut, and bend OUTWARD little "tabs" of the cap material.  I didn't get a pic of this, but once you get to it, you'll know.  Working carefully, open this hole to a TIGHT press fit against the inlet tube...Clean the can out VERY well at this point, then be sure to use the edge of the cutoff wheel to clean/abrade ALL of the edges where the inlet tube and the cap are going to be in contact.  The quality of the braze depends on this cleaning!!!  Braze the inlet tube in place, and be prepared to use some rod, as I had a couple of these that needed a lot of "filling" to seal...the brazing rod doesn't weigh much, and it's better to DO IT NOW than later.  Make sure you have a good seal, and it should end up something like this

JOINING THE HALVES - Prepare the fwd assy (inlet tube, and bottom of can with holes cleaned...) for brazing.  I use a grinding stone in the Dremel, and make sure I go all the way around the seam of the bottom of this can, inside edge, and outside edge, then clean it with alcohol.  Gotta be clean.  Prepare the aft assy similarly, except that you should just need to wipe off the area that you prepared before.  I join the halves by standing it vertically in a vise, inlet tube in the jaws of the vise, then balance and align the aft assy into the seamed edge of the fwd assy.  for appearance, I align the can seams lengthwise.  Put some weights on the flat top of the aft assy, enough to hold it steady, then braze the joint of the two halves.  Try not to use much rod, and more flux....when doing a good joint, it's only hot enough to flow the flux to clean it just before the rod melts and flows into the joint.  You may have to practice a bit, but once you get it figured out, it gets easy...here's the finished seam...  And the finished assembly weights....Oh, yes, the scale IS showing 5.7 oz.  Complete.  The black paint I use adds about another .1 oz.

Here's the finished muffler installed in my Viper...

Everyone wants to know the "bottom line"....well, this muffler sounds very pleasant to the hear, does not have a "tinny" sound at all, and definitely muffles adequately to have the prop and intake noise be what you notice.  As for rpm, well, my Webra turned about 7800 with 15% in 95 degree heat, 40% humidity.  APC 17 x 12 Standard prop.  Yep, that's good enough for us....and represents "quiet" made "cheap"....Try this project, if you're a tinkerer!!!