Oil Question

Go to the Penrite.com. website & look for the description of 'Friction Modified' oil. FM oils are 'thinner' to give better economy. Penrite make oils that are NOT FM'ed, which is what I use in my engines & engines that I build.

Not saying that the above is the reason for the oil pressure loss [ between different oils ] , cut it certainly could be. Usually a 10-15 psi loss at idle, hot; applies to syn & non-syn oil.