A nitrous oxide system for an internal combustion engine includes a bottle containing pressurized nitrous oxide coupled to a nitrous oxide flow line, which is in fluid communication with an injection nozzle operatively coupled to the engine intake. A control valve is fluidly coupled to the nitrous oxide flow line between the nitrous oxide bottle and the injection nozzle, and is operable to control the flow of nitrous oxide through the nitrous oxide flow line to the engine intake. A methanol injection line is in fluid communication with a source of supplemental methanol, and a methanol valve is fluidly coupled to the methanol injection line and operably coupled to the nitrous oxide flow line, such that a flow of pressurized nitrous oxide through the nitrous oxide flow line opens the methanol valve to allow a flow of supplemental methanol to the engine intake.