Hello, My factory service manual calls for: "60-70psi by 3,000 RPMs" this seems to be either really limiting my oil selection, or a crock of u know what written in a service manual 18 years ago. its 2.4L 4cyl DOHC Nissan making about 375whp and reving to 7500, track duty and hard street driving. I geeked out reading the forum and decided i needed to run a thinner oil. i pulled out last seasons 10w40 Castrol GTX for some 10w30 GTX (missing some data from runinng the 40wt last year). heres what i got: 10w40 idle @ 220F = 18-20psi idle @245F = 16psi 220F, 3k = ? (all i can recall is ~50 psi @ "cruising" on highway) 245F, 3k = ? WOT MAX = 80-85psi 10w30 idle @ 220F = 18psi idle @245F = 12-14psi 220F, 3k = 50-52psi 245F, 3k = ?? WOT MAX = 70psi motor is a little quieter at startup and i think while warm idle. i may have noticed a slight cooling bennefit from the added flow but tough to say, its like 40F outside. Despite not reaching the pressure requirement from the book i still think its a pretty well suiting oil. ill be adding an oil cooler soon. im guessing it will drop my temps 20-30F and will then be an even better suited oil. any thoughts for my rookieass? am i doing it wrong? am i on the right track? do i try a 20wt next? im just confused by the service manual spec.