During extensive development testing, S4 has proved to be an oil for extremes. Its wide viscosity range gives superior protection in conditions ranging from cold winter starts to the severe heat generated in racing engines. -Outstanding thermal and shear stability. -Superb wear protection. -Significantly reduces friction, releasing full engine power. -Passes crucial clutch friction test required to meet the JASO MA specification, allowing safe, predictable use in wet clutch applications. May be used where SAE 10W-40 is specified in owners handbook.