OK, Danno thanks , What I need to know is if I supply 6psi at one end of pipe, how many cfms can I flow thru one 2inch or two--1and1/2 pipes. with a endless supply of 6psi at one end.I'm looking for volume in cfms, compairing the 2' to the 1 1/2' .whats the max flow, with standard 29.92 pressure at the discharge end.