That’s funny. After lots of research it seems the best option for me is the 4” Gibson clamp-on mufflers. They’re priced between $600-737, depending where you buy them. The Borla 4-pipe mount setup is quality stuff but it’s overpriced imo, and it removes the collector extension area (4”) where the real scavenging is created in the header. That area, just downstream of the 4 to 1 collector, should ultimately be no less than a continuous constant diameter pipe of no less than 14”. At least this was the case in moto-GP bike exhaust. This isn’t hyperbole, it’s dyno proven. The same physics apply to these headers, the collector creating a venturi of high velocity exhaust gasses and the same diameter (4”) pipe must be maintained for no less than 14”. This creates a high velocity column of hot gases ripping through the tail section creating monster vacuum. Damn,… I need a cigarette.
So what about the Borla… they interrupt that continuous pipe section and you have to accept their science in lieu of the aforementioned dyno proven results. It’s a leap of faith at what they’re charging for these mufflers. Also, if you don’t care for the sound, db, or performance hit you get to weld the collector and tailpipes back on that you previously cut off to install the Borla.
At least with the Gibson mufflers, you clamp on aft of the continuous 4” pipe segment, you can remove both in 10 mins if you want open headers, and they’re much more affordable and they boast 304 stainless steel throughout.
Today I’m having delivered ChemicalGuys 2 disk 4” header insert. Yes, it will impede the gas flow some, but I’m willing to do that in order to reduce my db in a cost effective manner. It’s a gamble whether the compromise will be acceptable but it’s $130 I’m willing to wager. If it doesn’t fly then I’m buying the Gibsons.
Wet pipes don’t interest me. I have black Basset twisties that love heat as does the exhaust gas in the velocity sense.
What the hell just happened? Oh yeah, I had a second cup of coffee!