Octane booster raises the octane level of fuel to help improve performance and prevent engine knock and pre-detonation. Designed to be used at fill-ups, just add octane booster to the fuel tank for better fuel economy and higher performance. If you are experiencing engine knocking, octane booster can also help minimize the spontaneous combustion of your air-fuel mixture. Shop O'Reilly Auto Parts, where we carry octane boosters, fuel stabilizers, and fuel system cleaners to keep your vehicle running smoothly and at peak performance.