Quote: It simply sends the oil not needed back to the suction side of the pump to be recirculated through the pump again.
Correct. The effect is that it does not remove any more oil out of the pan. Chances are if the internal clearances are loose enough to suck the pan dry with a HV pump, it will also suck dry with a standard rotor pump and the same relief spring. I've never had a problem maintaining pressure with a std rotor in a loose motor at speed. Idle is another story.
