Rusty,
I only heard today that Al G. had flow data on his dyno.  He might have
some ideas around this.  As to head pressure, I believe I was taught
that head pressure only exists in an open system.  In a closed system it
all cancels out going around the circle.
But that was a long time ago ... Jim S.

Sorry; but there ain't no free ride; that would be tantamount to perpetual
motion.  Yes, if you add all the losses and offset it with the boost across
the pump, it equals zero.  But the pump has to do the work to overcome the
losses around the loop.  No pressure across the pump - no flow.

Al