Build Hydrogen Generator as Daniel Dingel of the Philippines did to his car, and other successful inventors like Dennis Klien, Stanley Meyer, Ronn Maxwell owner of Ronn Motors, and more of them on youtube.
Their inventions are based on hydrogen on demand concept usually using tumbler-like gadget inserted in the hood of the car that produces HHO or hydroxy gas sprayed into the combustion mechanism and the car runs. It's either using electrical pulse or simply electricity to fracture water into its base elements, and/or using chemical and metallic reactors, such as magnesium and salt water, for splitting water into hydrogen and oxygen.
Watch this series of videos on HHO fueled cars.
Stan Meyer's Water Car:
Dennis Klien's 1994 Ford Escort:
Daniel Dingel's Car:
Ronn Motors' 200 mph Hybrid - The Scorpion Supercar: