Winny911 said:
As oil may only be used up (not created) during use, some sort of "symmetric" argument is not valid.
Of course oil can't be created and I never said it could be.
What I actually said was that if it was critical to have an exact pressure then there would be an oil pressure alleviation system. Basically this works as an external reservoir to store excess oil when the pressure is to high and returns it to the engine when the pressure is to low.
In simple terms this works the same way as a header tank on a car radiator cooling system when the temperature gets too hot the pressure increases and the engine coolent is pushed into the header tank when the engine cools the pressure drops and coolent returns to the radiator.
My point was actually that the Porsche engine is designed to work over a range of pressures hence the max min thing on the dip stick and that the optimum pressure would therefore be directly I between the max and min and that if it was essential to keep the oil at max then they would not have created a min reading. They would have increased the tolerance and it would say keep it on max in the owners manual.