Oil + additive viscosity

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Im posting a pic of the oil gauge. This is taken at 3000 rpm cruise on highway. Its touching 50 psi. This is with 15w40 oil on a 20 degree Celsius day. If I was to open up more to 4000 RPM or more the pressure would drop even more into the mid 40's. Idle pressure when I pulled off the highway was just under 30 psi. As you step into street driving the pressure reads about 30 psi idle to 55 psi and remains there (idle to 3000 rpm varying). The temp is somewhat lower that before with the 20w60 oil which was running more closer to the 190 degree mark. Would one consider that the pressure is a little low?
Regards
Billy D...
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