Well, I'm curious what you're talking about, too.

As far as I know, every fluid pumping system is going to have flow limitations set by the size (restriction) of the passage(s), the viscosity of the fluid being pumped, the max free-flow volume of the pump, the max volume of the pump working against some set pressure (a product of the fluid's viscosity and that restriction), and any pressure-based blow-off limitation built into the system.

If the existing pump is already pushing the max capacity of fluid given the system's internal restrictions, and in the processs also hitting the peak pressure estabilished by the blow-off mechanism, then the only thing another pump could do differently is create more pressure from using a higher blow-off setting. However, the volume of fluid wouldn't increase signficantly past a certain point due to the limitation mentioned above.

Volume improvements under that scenario would need to come from enlarging the internal passage, not from trying to force-feed more oil through the same size passage.