Higher volume through an orifice doesn't increase the volume through the orifice? Sounds like a contradiction. Higher volume through the same orifice causes a higher pressure as a result of passing more volume. There is indeed an increase in volume.
In an engine, the HV pump increases volume only prior to the bypass opening. Once the bypass opens, it's no different really. The pump is only moving more oil per rpm, not pushing it harder and will only increase volume of flow prior to the bypass opening.
But any engine that will see significant load between idle and when the bypass opens, like many hot street motors, would benefit from a HV pump. A standard pump may not hit relief pressure until 3k rpm, where the HV may do it as low as 1500.
