Just do the pipe resonator it's on hear some where. You have it tuned to length for your specific exhaust.
---------- Post added at 12:22 AM ---------- Previous post was at 12:17 AM ----------
Found it.
A helmholtz resonator is really easy to make, it's harder to explain it to your local shop, than it is for them to make it. Most guys are gonna look at ya like you're crazy, I know that's what I did the first time I was asked to make one. Now, I've literally made hundreds of em for several different applications, including Raptor's. They're just a 26" (or so depending on the frequency you're trying to cancel out) piece of tubing branched into the exhaust system and capped on the end. There are a couple of different formula's used to figure out the length. There is helmholtz math, and 1/4 wave math. I've tried both on a Raptor, and they both work about equally as well.
---------- Post added at 12:24 AM ---------- Previous post was at 12:22 AM ----------
Or you can buy my om one not sure what they are worth or what it would coast to ship.