when empty i set the pressure at 40 psi with the tyre valve n guage thats connected. when the engine is hard on the transbrake limiter the oil system is up at 80 psi. it stays up there all the way to the finishline. when i'm braking the pressure drops but only down to 40 psi when the accumulator is now pressure feeding the system. before i fitted the accumulator it would drop right down to 15 psi which ok-ish since the engine is not under power, but i prefer it being no lower than 40 psi as oil is the life blood of a hipo engine. on the return road the hot oil is up about 55 psi. once shut off it takes about 8 secs to watch the oil pressure guage drop to zero.