Oil Pressure drop!

[jimbbski]

While trying to figure out why the car doesn't run "right" I keep seeing an oil pressure drop at the car warms up. At start up cold the pressure will rise to almost 80 psi and then hold at 70 psi for a bit. As the engine warms the pressure will drop down to around 40 psi at 1200 rpm. As the engine reaches normal opp. temp. say 180-190 on the guage the idle speed will drop below 1200 rpm and the oil pressure will drop down to 20 psi. It will even drop down as low as 10 psi if the revs drop below 800 rpm.

I am using Moble1 15W40 oil. I should say that the oil pressure will jump up as soon as I raise the engine speed to say 1500 and it will go as high as 60 psi as engine speed climbs to racing speeds.

I just have never seen this happen with any other engine that I have worked on that was in good mechanical condition. I know this one is as I have pulled the pan just a while ago with no metal in the bottom and cut a filter apart and found no metal there as well.

I guess I'm just wondering if this can be considered "normal" or with in the normal range for VW engines?