Royal Purple HPS 5W-30 motor oil is specifically formulated to maximize performance and meet the demands of high performance engines and modified engines. HPS, high performance street motor oil is recommended for vehicles no longer under manufacturer warranty and for those seeking a higher level of performance and protection. Royal Purple’s HPS is fortified with a high level of zinc/phosphorus anti-wear additive and Royal Purple’s proprietary Synerlec® additive technology. HPS outperforms other leading high performance synthetic oils and conventional lubricants for both gasoline and diesel high performance engines. Royal Purple HPS motor oil responds to increased pressure with increased viscosity. Thus Improved sealing between the piston ring and cylinder wall which maximizes power.