Turbosmart - OPRT40 Sleeper Oil Pressure Regulator 40psiTurbosmarts Patent Pending OPRT40 is an Oil Pressure Regulator designed for your Turbocharger. Many Turbochargers are built around a bearing and oil pressure profile much lower than is seen by modern & hi performance, engines and feeding these turbochargers the appropriate amount of oil pressure has always been a challenge. Traditional methods to limit oil pressure have been with a restrictor, aimed at reducing pressure However this also reduces flow.