optimal exhaust size

[jimfoo]

I have heard that cherry bombs actually have a fair amount of back pressure, even though you wouldn't think so.

[bevboyy]

I highly doubt that. They are basically a straight through glasspack. There is nothing in the exhausts way to cause any type of turbulence. They are highest flow next to straight pipe.

[jimfoo]

Years ago I used to work as a parts runner for an auto parts shop. At one of my stops, they had a chart of various brands & designs of mufflers and the back pressure. While the glasspacks were low, they weren't the lowest. I don't know if the ones they had were the louvered or perforated inner core, but I can see the louvered ones creating a fair bit of turbulence inside. The one with the lowest BP was a flowmaster or dynomax or something like that. It was years and years ago and I don't remember any more.