Ever since I was one of the first to install a custom muffler onto an SPF (see link below), I have been constantly asked every question under the sun regarding these.
Custom sidepipes - Phase I
More recently (the past year) several that did this have also noted a "fluttering" sound that is very distinguishable on deceleration. The cause appears to be the abrupt right angle of the weld that holds the perforated center section to the outer casing (stock SPFs have a cone like piece of metal that helps eliminate the same issue on their much smaller 2" ID factory mufflers). Given all the PMs and such, I can't recall who proposed doing the following mod:
CC member "carmine" has been considering doing something, so I whipped up the above drawing using Excel and converted it to a .jpg. As least this is how I perceived the mod based on a series of e-mails (long since tossed) that I shared with someone here! I'd like to hear if anyone has performed this mod and what the results were? It looks logical but would obviously require cutting them open and a complete ceramic re-coat (both of which I can't afford at the moment). But if this is the ticket, then I'm game for figuring out a way (Brian, are you listening)?
The whole Stainless Specialties muffler mod has been beaten to death here before (just do a search to confirm). But no one that I can recall has documented any mods to them to eliminate the very annoying fluttering sound when easing off the pedal and coming toward a stop.
Thanks everyone,
-Dean