OPRt40 Oil Pressure Regulator - BlueTurbosmart's 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 & high performance engines. Feeding these turbochargers the appropriate oil pressure has always been challenging. Traditional methods to limit oil pressure have been with a restrictor aimed at reducing pressure However, this also reduces flow.