AMSOIL DOMINATOR® 15W-50 100% SYNTHETIC RACING OIL

AMSOIL DOMINATOR 15W-50 100% Synthetic Racing Oil delivers SAE 50-grade protection in a multi-grade formula built to handle the elevated RPM, extreme heat, and shock-loading that racing engines endure. It is purpose-engineered for competitive motorsports applications where engine protection and horsepower output are equally critical.

Racing engines operate in a narrow margin between peak performance and catastrophic failure. Sustained high RPM, extreme combustion temperatures, and the mechanical violence of repeated shock-loading push oil far beyond what conventional or even standard synthetic formulations are designed to handle. An oil that shears down under these conditions loses viscosity, thins out, and leaves critical surfaces exposed at exactly the wrong moment. DOMINATOR 15W-50 is formulated specifically for this environment.

RESISTS VISCOSITY LOSS UNDER MECHANICAL SHEAR
High-RPM racing engines subject oil to extreme mechanical shear forces that can permanently thin out lesser formulations. When viscosity drops, the protective oil film between bearings, cams, and cylinder walls weakens. DOMINATOR 15W-50 is built with a shear-stable synthetic base that maintains its intended viscosity grade throughout the duration of a race. At 150°C under high-shear conditions (ASTM D5481), it holds an HTHS viscosity of 5.4 cP, confirming a robust and durable oil film even at extreme operating temperatures. Its kinematic viscosity of 17.9 cSt at 100°C (ASTM D445) stays where it needs to be, providing consistent SAE 50 protection lap after lap.

HEAVILY FORTIFIED ANTI-WEAR CHEMISTRY
Scuffing on flat-tappet cams, wrist pins, and other high-load contact surfaces is a real risk in race engines operating at sustained high loads. DOMINATOR 15W-50 is heavily fortified with zinc and phosphorus (ZDDP) anti-wear additives at levels well beyond what modern passenger car oils carry. In Four-Ball Wear testing (ASTM D4172, 40 kg, 150°C, 1800 rpm, 1 hour), the 15W-50 produced a wear scar of just 0.39 mm. This level of anti-wear protection is especially relevant for flat-tappet camshaft engines, aluminum block race builds, and turbocharged setups common in dirt late models, sprint cars, and endurance racing.

PROPRIETARY FRICTION MODIFIER MAXIMIZES HORSEPOWER
Every bit of energy lost to internal friction is horsepower that never reaches the wheels. DOMINATOR 15W-50 is formulated with a proprietary friction modifier designed to reduce parasitic drag inside the engine, translating directly to more usable power at the crankshaft. Cooler engine temperatures are a direct byproduct of reduced friction, which also contributes to longer component life over the course of an event or racing season.

EXCELLENT COLD-START AND PRE-RACE PROTECTION
Race engines don't always start hot. Whether you're firing up on a cold morning at a rally stage or during warm-up laps before a dirt late model feature, the oil needs to flow quickly and reduce drag before reaching operating temperature. DOMINATOR 15W-50 has a pour point of -38°C (-36°F) per ASTM D97, and its cold-cranking simulator viscosity (ASTM D5293) measures 6,062 cP at -20°C. That means faster oil delivery to critical surfaces at startup and less resistance during warm-up, when wear rates are at their highest.

THERMAL STABILITY FOR SUSTAINED HIGH-HEAT OPERATION
Race engines produce extreme heat, particularly in endurance formats, truck pulls, and turbocharged diesel racing applications. DOMINATOR 15W-50's thermally stable synthetic base stock resists oxidation and breakdown under these conditions. Its flash point of 238°C (460°F) and fire point of 272°C (522°F) per ASTM D92 reflect a formulation engineered to stay intact and keep protecting well into the punishing temperatures that racing demands. A total base number of 8.0 provides a strong acid-neutralization reserve throughout the oil's service life.

COMPATIBILITY AND APPLICATIONS
DOMINATOR 15W-50 is compatible with leaded and unleaded gasoline, diesel, alcohol, nitromethane, and nitrous oxide. It is suitable for domestic and import high-performance racing engines where an SAE 50 viscosity oil is recommended, including asphalt late models, dirt late models, modified big block engines, sprint cars, endurance racing, rally, truck pulls, aluminum block builds, marine racing, and diesel racing applications.

SERVICE LIFE
DOMINATOR is designed for racing use. When competing, the vehicle owner is responsible for determining an appropriate oil service interval based on the event, application, and viscosity needs. AMSOIL's Oil Analyzers Inc. division offers oil analysis services to help dial in the right change interval for your specific engine and racing program. DOMINATOR is not intended for long-term use in passenger cars or light trucks.