I hesitate to respond to this post, the poster's first. My question to this new BITOGer, is "where are you going with this." If the idea is to optimize fuel efficiency by managing the components and design that make up oil pressure... not really sure how practical that is. Obviously, if you have something causing low oil pressure, that needs to be fixed. Now, if the question is whether there is some point of great efficiency to be achieved at higher pressures, the answer is "no." You need enough pressure to move enough lubricant through oil passages at the desired RPM of the car. For a very high performance engine, you might need a specific pump. Based on the question, though, I suspect that if that were your situation, you'd know. If oil pressure is too high, that can cause leaks and component damage. Generally speaking, the manufacturer has you covered with a well-engineered solution to providing appropriate pressure across a broad range of operating conditions. My suggestion is to forget this particular question and focus on steady maintenance and frequent oil changes with in-specification, high quality oil.