AMSOIL DOMINATOR® 10W-40 100% SYNTHETIC RACING OIL

AMSOIL DOMINATOR 10W-40 100% Synthetic Racing Oil delivers straight-grade SAE 40 protection in a multi-viscosity formula built for engines that spend their lives at wide-open throttle. It is purpose-engineered for high-RPM, high-temperature racing applications where viscosity stability, wear protection, and friction reduction directly affect what shows up on the time slip.

Racing engines live in a brutal environment. Sustained high RPM shears lesser oils down to viscosities they were never designed to operate at, leaving bearings and cylinder walls exposed. Extreme combustion temperatures cook conventional and even some synthetic base stocks, breaking down additive chemistry when it matters most. The consequences are scuffing, accelerated cam and lifter wear, and lost horsepower over the course of a race.

RESISTS VISCOSITY LOSS UNDER MECHANICAL SHEAR
An oil that thins out under load cannot maintain the protective film thickness your engine needs. DOMINATOR 10W-40 is built with a shear-stable synthetic base stock that holds its viscosity even under the extreme mechanical stress of high-RPM racing. It posts a high-temperature/high-shear (HTHS) viscosity of 4.6 cP at 150°C per ASTM D5481, confirming that it maintains a durable oil film at the bearing surfaces where temperatures and shear rates peak. This is the metric that separates a race-ready oil from one that just looks good on a shelf.

HEAVY ZINC AND PHOSPHORUS ANTI-WEAR FORTIFICATION
Flat-tappet cams, high-lift valve springs, and aggressive lobe profiles generate contact pressures that overwhelm standard additive packages. DOMINATOR 10W-40 is heavily fortified with zinc and phosphorus (ZDDP) anti-wear additives, providing a sacrificial chemical barrier against metal-to-metal contact in the valve train, piston skirts, and wrist pins. In Four-Ball Wear testing per ASTM D4172, DOMINATOR 10W-40 produced a wear scar of just 0.39 mm under 40 kg of load at 150°C for one hour. For sprint car engines, dirt late models, modified big blocks, and aluminum block builds where cam and lifter protection is non-negotiable, this level of anti-wear chemistry is exactly what the engine needs.

PROPRIETARY FRICTION MODIFIER MAXIMIZES HORSEPOWER
Every unit of energy consumed by friction inside the engine is energy that never reaches the wheels. DOMINATOR 10W-40 is formulated with a proprietary friction modifier package that reduces internal parasitic drag, translating directly to more usable horsepower and cooler operating temperatures. Cooler engine temps also help preserve the oil itself, keeping viscosity and additive chemistry intact deeper into a race or a long qualifying session.

EXCELLENT COLD-START AND PRE-RACE PROTECTION
Even in a racing environment, cold oil causes problems. The warm-up laps before a green flag or the initial fire-up on race morning are high-risk moments. DOMINATOR 10W-40 has a pour point of -42°C (-44°F) per ASTM D97 and a cold-crank simulator viscosity of 6,493 cP at -25°C per ASTM D5293. That translates to less drag during warm-up and faster oil delivery to critical surfaces before the engine reaches stable operating temperature. It flows like a multi-grade and protects like a straight 40-weight.

THERMAL STABILITY AT EXTREME OPERATING TEMPERATURES
Racing engines routinely exceed oil temperatures that would break down street-grade oils. DOMINATOR 10W-40 uses thermally stable synthetic chemistry that resists oxidation and thermal degradation under sustained heat. Its flash point of 224°C (435°F) and fire point of 232°C (450°F) per ASTM D92 reflect a base stock that holds together when combustion temperatures and oil sump temps spike during extended green-flag runs.

APPLICATIONS AND COMPATIBILITY
DOMINATOR 10W-40 is designed for domestic and import high-performance racing engines where an SAE 40 viscosity oil is appropriate. Specific applications include asphalt late models, dirt late models, modified big block and small block builds, sprint cars, aluminum block engines, GM crate late model engines, and marine racing applications. It is compatible with leaded and unleaded gasoline, diesel, alcohol, nitromethane, and nitrous oxide fuels. A total base number (TBN) of 8.0 provides strong acid-neutralizing capacity across a range of fuel types.

SERVICE LIFE
DOMINATOR is not intended for long-term use in passenger cars or light trucks. The vehicle owner is responsible for determining an appropriate service interval based on the specific event, application, and viscosity needs. Oil analysis through Oil Analyzers Inc. (a division of AMSOIL) is available for racers who want data-driven drain interval decisions.