I recently installed an oil pressure gauge in my motor and started to take note of the oil pressures at different RPM. The oil pressure sensor is mounted using a sandwich plate between the oil filter and block on my Honda K20a2 motor. My understanding is that this gives the pressure before the filter media. I use mobil 1 15w-50 oil with a Bosch 3312 oil filter. I've noticed that the oil pressures I see are relatively high, 70psi by 2000rpm with the oil at 200-5deg. At 9000rpm I'm seeing 110psi on the gauge. Since I'm using a thicker oil along with an oil filter made for the S2000 (Honda F20c engine, it's a larger filter than the 3323 that is suggested for the k20a2), I'm concerned about whether the bypass valve is staying open more frequently than it should. I did some searching in this forum and couldn't find any info on how to go about determining what the bypass valve opening PSI is. My idea is: 1) Measure the pre filter pressure from the sandwich plate 2) Measure the post filter pressure from the main oil galley 3) subtract 2) from 1) to get a rough idea of pressure differential across oil filter media Then I can compare the measured pressure differential to bypass valve ratings to find one that will stay closed in almost all conditions when the engine is at operating temp. Is my thinking correct on that? Thanks in advance!