Long story short:

To throttle air from a centrifugal blower powered by a 3/4 HP motor I am considering swapping in a 1/3 HP motor and reset the pulley size to optimize the motor current/RPM. The motor will still run at 1725 RPM but the blower will be running slower and therefore produce less air flow. However, I would still like to maximize the flow with the 1/3 motor to get the best flow possible at lowest energy usage.

Question:

In general would swapping in a matching blower designed for 1/3 HP produce significantly more flow than the bigger blower which runs at a slower speed?

I seem to remember the flow vs RPM curve for blowers is somewhat linear. Any thoughts?

Many thanks....