If you are only looking for the 1 psi boost claimed by the eRam people you will need about 2 hp for a 400 ACFM discharge at 100F. This is approximatly 1500 Watts. The eRam claims to be a 700 watt system so two should just about do it. But, I doubt the fan will move that 200 ACFM of air against a 1 psi head. Of course, the 700 watts may be the power demand as well and not the power output of the motor.