What is "engine knock" and why does it matter? "Knock" is an uncontrolled and explosive ignition of a hydrocarbon fuel, such as gasoline, in the combustion chamber. It causes a knocking or pinging sound, robs the engine of power and, left unchecked, causes serious engine damage. Fuel's tendency to knock is measured by its octane number. Lower numbers denote greater knock tendency; higher numbers denote greater knock control. Knock may be eliminated with the appropriate octane number. AMSOIL products are backed by a Limited Warranty.
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Product data sheets
View, download, or save a copy of the Product Data Sheet or Safety Data Sheet for AMSOIL DOMINATOR® Octane Boost.
AMSOIL DOMINATOR Octane Boost (AOB) is a racing-grade fuel additive built for high-compression, turbocharged, supercharged, and high-output two- and four-stroke gasoline-fueled engines. One treatment of this concentrated booster raises the octane rating of pump gasoline by up to four numbers, reduces engine knock under load, improves ignition, and helps fuel burn cleaner. Sale is limited to off-road and racing use only.
Built for off-road and racing service
DOMINATOR Octane Boost is the recommended octane booster for high-performance off-road and racing applications. The concentrated chemistry is engineered to push effective octane well past what street-grade pump gasoline delivers, which is why distribution is limited to off-road and competition use. Dedicated race cars, sand rails, mud trucks, drag bikes, performance ATVs and UTVs, racing snowmobiles, and modified pickups all sit inside the design window for this booster.
Octane lift of up to four numbers
Each bottle is formulated to raise the octane rating of pump gasoline by up to four numbers. The recommended dose is one 12-ounce (354 mL) bottle for 15 gallons (57 litres) of gasoline, which most users find delivers the ideal performance increase. Higher octane numbers denote greater knock control, so the additive lets a builder start with a lower grade of pump fuel and bring it up to the octane window an aggressive tune calls for.
Reduced engine knock and improved ignition
Engine knock is an uncontrolled and explosive ignition of a hydrocarbon fuel, such as gasoline, in the combustion chamber. The pinging or knocking sound that results is more than a noise issue. Detonation robs the engine of power and, left unchecked, causes serious engine damage to pistons, rings, bearings, and head gaskets. DOMINATOR Octane Boost reduces engine knock, improves ignition, and restores responsiveness in engines that are otherwise running on the edge of detonation.
Engines with higher static compression ratios, forced induction, advanced timing, or aggressive tune files are the most sensitive to fuel octane and the most likely to benefit from a fuel-side boost. A consistent treat rate also helps keep knock sensors and electronic countermeasures from pulling timing or boost on every hard pull.
Cleaner combustion and carbon control
In addition to raising effective octane, DOMINATOR Octane Boost helps fuel burn cleaner and removes carbon deposits. Cleaner combustion supports smoother ignition events, more complete fuel burn under load, and reduced deposit buildup on intake valves and combustion chamber surfaces over time. The result is a more responsive throttle, fewer unburned fuel events, and a more predictable performance envelope.
Lead substitute for collector and older off-road engines
DOMINATOR Octane Boost is also excellent as a lead substitute at the same treat rates in collector automobiles, older off-road equipment, and pleasure vehicles. Many vintage and older racing engines were designed around leaded fuel for valve-seat protection and knock control. Use of this booster keeps those engines running on the unleaded pump gasoline available today without losing the octane headroom their factory tune was built for.
Recommended applications and service intervals
DOMINATOR Octane Boost is intended for off-road and racing use only in two- and four-stroke gasoline-fueled engines. Treat per tank, not per service interval, since the additive has to be present in the fuel during combustion to lift octane. To match the product to a specific vehicle, equipment piece, or engine, run the application through the AMSOIL vehicle lookup guide.
Normal racing or off-road performance use: one 12-ounce (354 mL) bottle per 15 gallons (57 litres) of gasoline per tank for the ideal performance increase.
Lead substitute use in collector automobiles, older off-road equipment, and pleasure vehicles: same treat rates as the performance dose.
Not for use on public roads, in emissions-controlled vehicles, or in any application where local law prohibits non-street fuels or additives.
Outside the United States and Canada, confirm local regulations on octane boosters and racing fuel additives before use.
DOMINATOR Octane Boost is intended as a single treatment per tank in gasoline-fueled two- and four-stroke engines. For ethanol-blended pump gasoline in powersports and seasonal equipment that sits between rides, a separate ethanol-control additive is the right tool. See the AMSOIL Quickshot guide for how AMSOIL Quickshot pairs with an octane booster in mixed-use fleets.
Order AMSOIL DOMINATOR® Octane Boost
DOMINATOR Octane Boost (AOBBE) is stocked in a 12-ounce bottle (AOBBE-EA) and a case of six 12-ounce bottles (AOBBE-CA). The product is backed by the AMSOIL Limited Liability Warranty. Match the right product with the AMSOIL vehicle lookup guide and compare related fuel additive choices in the AMSOIL Quickshot guide, then place an order through AMSOIL DOMINATOR Octane Boost.
At first i was scepticle about the octane rating, bought the product, bought the octane test strips and yes it brings the numbers up 💯 percent!
By Dave from Kapuskasing on June 25, 2026.
Would recommend this to a friend.
Good stuff
Great price Quick Delivery and is working great 👍
By Keith on June 18, 2026.
Would recommend this to a friend.
Buy Now
I purchased three products from AMSOIL, The Upper Cylinder Lubricant Corrosion Inhibitor, The DOMINATOR® Octane Boost, and The P.i.® Performance Improver Gasoline Additive I added all three to a full tank but, prior to doing this, I had filled the tank with Top Tier Fuel for this test Shortly after I took a ride, at first, I noticed nothing, but the very next day I put twenty miles on her, and that is when I noticed she ran quieter, and that the pick-up was back I highly recommend this product for older vehicles, and I want you to know, that these products are not a gimmick Check it out for yourself
DOMINATOR Octane Boost raises the octane rating of pump gasoline by up to four numbers, reduces engine knock, improves ignition, and helps fuel burn cleaner in two- and four-stroke gasoline-fueled engines. It is engineered for high-performance off-road and racing applications where pump gasoline alone is not enough to keep an aggressive tune out of knock.
How much DOMINATOR Octane Boost should be added per tank of gas?
The recommended dose is one 12-ounce (354 mL) bottle for 15 gallons (57 litres) of gasoline. Most users find this treat rate delivers the ideal performance increase. The booster is added at the pump so the incoming fuel charge mixes the additive into the tank.
Can DOMINATOR Octane Boost be used on the street?
No. DOMINATOR Octane Boost is sold for off-road and racing use only in two- and four-stroke gasoline-fueled engines. For emissions-controlled street vehicles, select a gasoline additive that is intended for on-road use.
Does DOMINATOR Octane Boost work in two-stroke engines?
Yes. The formula is designed for both two- and four-stroke gasoline-fueled engines, which covers most performance off-road powersports, racing snowmobiles, dirt bikes, and small engines that run on gasoline plus pre-mix or oil-injection systems.
Is DOMINATOR Octane Boost an effective lead substitute for older engines?
The product is suited for use as a lead substitute at the same treat rates in collector automobiles, older off-road equipment, and pleasure vehicles. Owners of vintage engines originally designed for leaded fuel run this booster to support knock control on the unleaded pump gasoline available today, without changing the underlying tune or compression ratio.
How does DOMINATOR Octane Boost compare with AMSOIL Quickshot?
The two additives solve different problems. DOMINATOR Octane Boost raises octane and reduces engine knock for high-output and racing applications. AMSOIL Quickshot targets ethanol-related fuel issues such as phase separation and water absorption in powersports and small engines that sit between rides. Both additives can be carried in the same shop for different jobs, and the AMSOIL Quickshot guide covers when each one is the right call.
Octane lift of up to four numbers
Each bottle is formulated to raise the octane rating of pump gasoline by up to four numbers. The recommended dose is one 12-ounce (354 mL) bottle for 15 gallons (57 litres) of gasoline, which most users find delivers the ideal performance increase. Higher octane numbers denote greater knock control, so the additive lets a builder start with a lower grade of pump fuel and bring it up to the octane window an aggressive tune calls for.
Reduced engine knock and improved ignition
Engine knock is an uncontrolled and explosive ignition of a hydrocarbon fuel, such as gasoline, in the combustion chamber. The pinging or knocking sound that results is more than a noise issue. Detonation robs the engine of power and, left unchecked, causes serious engine damage to pistons, rings, bearings, and head gaskets. DOMINATOR Octane Boost reduces engine knock, improves ignition, and restores responsiveness in engines that are otherwise running on the edge of detonation.
Engines with higher static compression ratios, forced induction, advanced timing, or aggressive tune files are the most sensitive to fuel octane and the most likely to benefit from a fuel-side boost. A consistent treat rate also helps keep knock sensors and electronic countermeasures from pulling timing or boost on every hard pull.
Cleaner combustion and carbon control
In addition to raising effective octane, DOMINATOR Octane Boost helps fuel burn cleaner and removes carbon deposits. Cleaner combustion supports smoother ignition events, more complete fuel burn under load, and reduced deposit buildup on intake valves and combustion chamber surfaces over time. The result is a more responsive throttle, fewer unburned fuel events, and a more predictable performance envelope.
Lead substitute for collector and older off-road engines
DOMINATOR Octane Boost is also excellent as a lead substitute at the same treat rates in collector automobiles, older off-road equipment, and pleasure vehicles. Many vintage and older racing engines were designed around leaded fuel for valve-seat protection and knock control. Use of this booster keeps those engines running on the unleaded pump gasoline available today without losing the octane headroom their factory tune was built for.
Recommended applications and service intervals
DOMINATOR Octane Boost is intended for off-road and racing use only in two- and four-stroke gasoline-fueled engines. Treat per tank, not per service interval, since the additive has to be present in the fuel during combustion to lift octane. To match the product to a specific vehicle, equipment piece, or engine, look up your vehicle in the AMSOIL vehicle lookup guide.
Normal racing or off-road performance use: one 12-ounce (354 mL) bottle per 15 gallons (57 litres) of gasoline per tank for the ideal performance increase.
Lead substitute use in collector automobiles, older off-road equipment, and pleasure vehicles: same treat rates as the performance dose.
Not for use on public roads, in emissions-controlled vehicles, or in any application where local law prohibits non-street fuels or additives.
Outside the United States and Canada, confirm local regulations on octane boosters and racing fuel additives before use.
DOMINATOR Octane Boost is intended as a single treatment per tank in gasoline-fueled two- and four-stroke engines. For ethanol-blended pump gasoline in powersports and seasonal equipment that sits between rides, a separate ethanol-control additive is the right tool. See the AMSOIL Quickshot guide for how AMSOIL Quickshot pairs with an octane booster in mixed-use fleets.
Order AMSOIL DOMINATOR® Octane Boost
DOMINATOR Octane Boost (AOBBE) is stocked in a 12-ounce bottle (AOBBE-EA) and a case of six 12-ounce bottles (AOBBE-CA). The product is backed by the AMSOIL Limited Warranty. Match the right product with the AMSOIL vehicle lookup guide and compare related fuel additive choices in the AMSOIL Quickshot guide, then place an order through AMSOIL DOMINATOR Octane Boost.
Frequently asked questions
What does AMSOIL DOMINATOR Octane Boost do?
DOMINATOR Octane Boost raises the octane rating of pump gasoline by up to four numbers, reduces engine knock, improves ignition, and helps fuel burn cleaner in two- and four-stroke gasoline-fueled engines. It is engineered for high-performance off-road and racing applications where pump gasoline alone is not enough to keep an aggressive tune out of knock.
How much DOMINATOR Octane Boost should be added per tank of gas?
The recommended dose is one 12-ounce (354 mL) bottle for 15 gallons (57 litres) of gasoline. Most users find this treat rate delivers the ideal performance increase. The booster is added at the pump so the incoming fuel charge mixes the additive into the tank.
Can DOMINATOR Octane Boost be used on the street?
No. DOMINATOR Octane Boost is sold for off-road and racing use only in two- and four-stroke gasoline-fueled engines. For emissions-controlled street vehicles, select a gasoline additive that is intended for on-road use.
Does DOMINATOR Octane Boost work in two-stroke engines?
Yes. The formula is designed for both two- and four-stroke gasoline-fueled engines, which covers most performance off-road powersports, racing snowmobiles, dirt bikes, and small engines that run on gasoline plus pre-mix or oil-injection systems.
Is DOMINATOR Octane Boost an effective lead substitute for older engines?
The product is suited for use as a lead substitute at the same treat rates in collector automobiles, older off-road equipment, and pleasure vehicles. Owners of vintage engines originally designed for leaded fuel run this booster to support knock control on the unleaded pump gasoline available today, without changing the underlying tune or compression ratio.
How does DOMINATOR Octane Boost compare with AMSOIL Quickshot?
The two additives solve different problems. DOMINATOR Octane Boost raises octane and reduces engine knock for high-output and racing applications. AMSOIL Quickshot targets ethanol-related fuel issues such as phase separation and water absorption in powersports and small engines that sit between rides. Both additives can be carried in the same shop for different jobs, and the AMSOIL Quickshot guide covers when each one is the right call.
