I agree at operating temp I doubt we will ever open the bypass valve (especially on the Royal Purple) on any filter. I question on cold start-up however when viscosity is 100's of Cst. This weekend we have a little cool front comming through. I plan on testing the RP, the FL-1A and FL-1HP.
I am 99% convinced the best filter on the market is the Royal Purple. I cut one up last night, it even has a wire mesh on the dirty side of the
synthetic filter media to maintain pleat spacing on the filter element. It is built like a dump truck. I cant wait to see if I can register a pressure drop across it. 99% efficiency at 25 microns, and little to no differential pressure according to their data.
Just got confirmation from RP that bypass is set 9-11 psig and clean side by-pass which I verified last night.