Originally Posted By: Izb
What is the source if this graph?
Is difference (in PSID )of Ultraguard (from ChampLabs?) and Mobil-1 (semisynthetic) 2x (graph#1) or 4x(graph#2)?
I believe it was created by AC Delco. Notice how the AC Delco filters (Ultraguard and Duraguard) are in bold letters. I know the (old) graph you posted below mine was from AC Delco because I emailed them years ago about that same graph with questions. Notice though that the Duraguard doesn't show as good of comparative flow performance in the hot oil graph as it does in the cold oil graph ... seems kind of fishy to me.
I know the AC Delco Ultraguard was a fill synthetic filter, and it shows in the chart. I have no idea what filters are "Competitor #x", but like I said before, the difference with hot oil at 5 GPM is only a spread of 1.5 PSI between the worst to the best flowing filter. That says all these filters flow way better than any engine could ever tell the difference between them in normal driving conditions. At full tilt of 10 GPM for some high output pumps, the difference is 5 PSI. Still probably not enough difference to make a difference to the engine, but if someone was concerned about getting every possible oil flow to the engine at redline then they would want to go for a full synthetic oil filter.