You can set them up with a solenoid so they only open below a set pressure. That's for a street car to solve the hastle of opening and closing a manual valve. I ran a manual valve on my car and left it close on the street. (Mixed the oil up once in a while to burn off moisture) I'd then just open it on track days and rev up the engine an close it at the end of the day. Beat the ever living crap out of my car and never had an engine problem. That and a great engine builder.
