That is an excellent question and one I have thought of asking myself. People say that their K&N filters give them more pressure, but that is not possible. The filter is not changing the pump at all. If anything, it may make a restriction that bumps up the PSI on the upstream side of the fiter. My guess would be that the sending unit is between the pump and filter. If the filter has more resistance, the pump discharge PSI will be higher. That does not mean there is more flow, or that the entire system has higher PSI.