Oil Pressure Gauge Finally Working, 3S-GTE Oil Pressure Options

[Fastbird]

Tuner Toys adapter came in today. Just got it hooked up after the wife came home from work with the car. Now my question.....

What's oil pressure supposed to be at for the 3S???? Right now it's at 10-20 PSI at idle and at 1500 RPM's it's come up to around 40 PSI, and on a free rev up to about 3500-4000 RPM the pressure comes up to about 58 PSI. The load (if you want to call an idle rev that) pressure responds for what I consider to be fine (approx 10 PSI per 1K rpm), but I'm left wondering if the idle pressure is low at all. Eighteen PSI at idle to me just isn't the best.

Which leads me to this question: Obviously the oil pressure sending unit is on the head. But where on the head does it actually take the pressure reading from?? Is it a open area on the head with oil flowing around it or is it actually in an oil passage?

Thanks guys.