Patman
Staff member
I just recently found out that pretty much all of the oil filters that cross reference to the AC Delco PF64 oil filter (which my Corvette uses) also have a lower bypass pressure. The PF64 is set to 22psi, but from what I've found, the Ultra is around 15psi, and same with the Wix/NAPA Gold (unless you go to a longer version of it) There is even a technical service bulletin for the Corvette warning of using those filters with a lower bypass pressure. But their explanation makes it sound more like it would simply not be filtering the oil as often, so if anything I would think the lower psi would be better for harder driving because then the oil flow would be better. Does this make sense? For now I am going to be sticking to the PF64. But eventually I'd like to switch to the Fram Ultra.