AMSOIL DOMINATOR 100% SYNTHETIC 2-STROKE RACING OIL

Two-strokes that call for an API TC oil

Run it in high-performance stock or modified two-stroke engines, which covers air-cooled and liquid-cooled snowmobiles, personal watercraft, motorcycles, ATVs, go-carts, and outboard motors. API TC is the performance category behind that list. A two-stroke burns its oil with the fuel charge instead of recirculating it, which is why the category exists at all. Your engine has to call for an API TC oil before this one belongs in the tank.

That list runs wide because it describes a shared requirement, not a single kind of machine. A go-cart engine and a liquid-cooled sled have almost nothing in common beyond a two-stroke cycle and a lubricant that arrives with the fuel and leaves through the exhaust. What ties them together here is racing duty, where an engine spends long stretches near peak output instead of loafing along.

Premix at 50:1 or run it through injection

Premix at 50:1, which comes to 2.6 ounces of oil per U.S. gallon of gasoline. Many racers modify the mix ratio to suit their setup, so let your class rulebook or your engine builder override the general figure. Because the oil arrives dissolved in the fuel, the ratio you pour at the can is the only control you have over how much lubricant reaches the crankcase.

The same oil serves oil-injected applications that require API TC oils. Both methods on one label does not make them interchangeable on one engine. An injection system meters oil against throttle position and engine speed, so a machine equipped with one runs straight gasoline in the tank, and a machine without one has no other way to get lubricant in. Your engine picks the method, and the oil covers either.

Film strength past 10,000 rpm

Carefully selected higher-viscosity synthetic base oils handle the heat and pressure that come with high-performance and racing work. Film strength is what protects an engine that can exceed 10,000 rpm, where every revolution gives the oil less time to re-establish itself between loaded parts. Race-proven anti-friction chemistry adds another measure of protection against piston scuffing and bearing wear.

Kinematic viscosity is 35.2 cSt at 40°C and 7.0 cSt at 100°C under ASTM D445, and relative density is 0.8708. Those numbers describe the neat oil in the bottle, before it gets diluted into fuel at 50:1 or metered by an injection pump, so they characterize the concentrate rather than the mixture that reaches the crankcase. Viscosity at the point of lubrication depends on the ratio you actually run.

Carbon, plug fouling, and the fuels that are out

Clean-burning synthetic base oils and high-temperature detergent additives handle deposit control. The target is power-robbing carbon, which causes ring sticking, exhaust port blocking, and pre-ignition. Each of those costs output before it costs parts, since a stuck ring loses its seal, a blocked exhaust port chokes scavenging, and pre-ignition puts combustion pressure against a piston still on its way up the bore.

Burning clean also helps prevent plug fouling, the everyday symptom of an oil leaving residue in the combustion chamber. The oil is good for use with exhaust power valves and protects coated and non-coated racing pistons, the two components most sensitive to how a two-stroke oil behaves. Power valves sit right in the exhaust stream where carbon binds their travel, and that is the same carbon the detergent additives are formulated to control.

Two fuel restrictions apply. The oil is not suitable for use with alcohol or nitromethane fuels, which rules it out of classes running methanol or nitro no matter how well your engine matches the rest of the list. It is good for use with high-octane racing fuels, so race gasoline stays inside the range while exotic fuel chemistry sits outside it.

Outboard limits, cold flow, and six package sizes

Outboard use carries its own limit. The oil is not suitable for long-term use in outboard motors as a TC-W3 type oil, though it works as a race oil for short-term outboard use where motors get inspected periodically. TC-W3 is the water-cooled two-stroke marine category, and the line here separates a season of general boating from a race weekend with teardowns between events.

Pour point is -54°C (-65°F) under ASTM D97. Pour point marks where a chilled sample stops moving in the laboratory rather than setting an operating floor, but a figure that low matters for a snowmobile injection tank sitting outdoors between runs, since the system has to draw oil at whatever temperature the machine starts in. Flash point is 94°C (201.2°F) and fire point 94°C (201°F) under ASTM D92.

Six package options cover it. TDRQT-EA is the quart bottle and TDRQT-CA the case of twelve, TDR1G-EA is the gallon jug with TDR1G-CA covering a case of four, and for bulk, TDR16-EA is the 16 gallon keg and TDR55-EA the 55 gallon drum. The oil is compatible with most other two-stroke oils, though keep mixing to a minimum, since fuel already blended with another oil shifts the ratio away from the one you meant to run.

Verified specifications