Disclaimer: I know next to nothing about muffler design and I am not here to badmouth Heartthrob! This is simply my findings and well, I'm kinda confused and hoping someone might shed some light here. Also, I'm an engineer and it's in my DNA to question the entire effing universe.
Previously, I purchased a Moroso 94051 3" spiral flow muffler to go on the Daytona. I've since been following the "Daytona drone" thread, and decided to buy a Heartthrob HVS muffler to go on instead. Taking my nice new HVS 44044 muffler out of the box, immediately I was a bit confused. It is definitely 3" in, 3" out as I ordered:
...but it immediately necks down quite a bit. I didn't have verniers that would reach deep enough to measure, so I found something that fit snug and measured that.
That's not 3", that's more like 2-1/8". I understand that it's a chambered muffler and it will have a little bit of restriction in the design, but that seems like a drastic difference in size. I emailed Jeremy at Heartthrob, who has been very helpful so far. We'll see what he says. With all of this said, the guys in the Daytona drone thread are using the 54044 instead of the 44044 that I bought. Mine has a bit smaller body to make mounting in the stock location easier. Maybe it's a totally different design.
Bit of a head-scratcher to me. Anybody have experience with the spiral flow mufflers in case this doesn't pan out?