oil pressure
 

just wondering what oil pressure should be at idle, cruising, wot, im just going by the factory oil pressure gauge but mine is about 15 at idle, 30 exactly, and 45 wot is that what it should be????

Sounds good to me. Is that cold or hot? Lots of boost or none? The viscosity and life left in your oil will affect your oil pressure as well.

Indeed. Temperature is probably the biggest factor in oil pressure. Next are viscosity and filter quality.

My engine, when stone cold, idles at ~50 PSI, and exceeds 90 PSI (the limits of the gauge) at 3,000 RPM.

At normal operating temperature, idle is ~25 PSI, ramping up to 60 PSI at 4,000 RPM or above.

When very hot, oil pressure may be as low as 10-15 PSI idle, up to 45-50 PSI at 4,000 RPM.

This is with M1 0W40 and an M1-104 filter. Every engine seems to be a little difference. I suspect that some of that variance may actually be due to the gauge itself. A 17 year oil stock oil pressure sensor is probably not a NIST-quality instrument.

okay guys so im goin to change my oil real soon and Im in IL and it gets pretty cold here so what should i run this fall/winter 10w30?

Try this sub-forum.

https://www.miataturbo.net/forums/forumdisplay.php?f=4