Abstract: The superheater of the invention is provided for the purposes of improving the efficiency and cleanliness of gasoline internal combustion engines which are used extensively and which are the usual motive power of automobiles. The superheater includes a housing or chamber which may be assembled in communication with the fuel supply tank of an internal combustion engine. It includes means such as a connection with the engine cooling system for heating gasoline in the housing or chamber to a temperature above its normal boiling point while the gasoline is held in its liquid state under pressure. It also includes means for controlling the pressurized flow of the superheated gasoline to the fuel input of the engine. In the embodiment illustrated, a heating coil is provided in the chamber so that heated engine cooling fluid may pass through the housing or container and thus heat the gasoline without coming in actual contact with the gasoline.