AMSOIL Briggs & Stratton Synthetic 4T Racing Oil is a purpose-built synthetic racing oil developed jointly by Briggs & Stratton engineers and AMSOIL for high-rpm, air-cooled four-stroke competition engines. It was engineered to deliver maximum usable horsepower while protecting against the extreme heat, shear and foaming conditions found in karting and other small-engine motorsport applications.

Unlike ordinary automotive oils or generic karting lubricants, Briggs & Stratton Synthetic 4T Racing Oil is formulated specifically for competition engines. It combines low internal friction with strong film strength and high-temperature stability, helping racers extract performance without sacrificing engine protection.

Built for Air-Cooled Racing Engines

Small air-cooled competition engines can operate at high temperatures for extended periods, particularly in kart, junior drag and quarter midget racing. Synthetic 4T Racing Oil uses high-quality synthetic base oils that resist thermal breakdown and oxidation, helping control deposits, maintain oil performance and support consistent engine operation under severe racing conditions.

Maximises Horsepower

Synthetic 4T Racing Oil is engineered to provide the low-friction characteristics racers want from a lighter oil while maintaining the wear protection expected from a heavier lubricant. Specialised friction modifiers help reduce parasitic friction inside the engine, allowing more of the engine's available power to reach the driveline.

High-RPM Wear Protection

High engine speed can introduce aeration and foaming into the oil, reducing its ability to maintain a protective lubricating film. Synthetic 4T Racing Oil contains powerful anti-foam additives that help maintain oil-film integrity during sustained high-rpm operation, protecting bearings, cylinder walls and other heavily loaded components.

Resists Heat, Deposits & Corrosion

Its thermally stable synthetic formulation helps resist sludge and deposit formation caused by extreme operating temperatures. Built-in corrosion inhibitors also help protect internal engine surfaces between race meetings and during longer periods of storage.

Applications & Recommendations

Recommended for stock and modified small-displacement air-cooled four-stroke competition engines used in karting, junior drag racing, quarter midget racing and other motorsport applications. Suitable for single- and multi-cylinder engines, including splash-lubricated and pressure-lubricated designs, where the required viscosity and operating characteristics are appropriate.

Briggs & Stratton Synthetic 4T Racing Oil is suitable for both gasoline- and alcohol-fuelled competition engines and is compatible with conventional mineral engine oils.

Ideal For

• Four-stroke racing kart engines
• Briggs & Stratton competition engines
• Air-cooled small racing engines
• Junior drag racing engines
• Quarter midget racing engines
• Stock and modified competition engines
• Gasoline- and alcohol-fuelled racing engines