Inliners International Forums General Discussion Engines 2 Barrel vs 4 Barrel

But... 2 bbl. and 4 bbl. aren't rated at the same pressure drop.
A 2 bbl. identified by the manufacturer as 390 CFM actually flows 276 CFM @ 1.5" Hg.
A 4 bbl. identified by the manufacturer as 390 CFM actually flows 552 CFM @ 3" Hg.