There is no comparison between a roots blower at 17psi and a 62mm turbo at 17psi. The turbo is going to move more air. I've got logs showing a 62mm a 16-18psi and max maf ad counts were 820's, load 160. Switched to an s366 and 870/190. So the 66mm was moving more air as it showed in fuel trims and mph at the strip.