[Hummer Dog]

You can't make an efficient hydrogen refinery from a gasoline engine powered alternator. These systems remind me of perpetual motion claims.

I don't think you'll see any gains from water injection on a modern engine, unless your engine is running with retarded spark, you won't make more power or get better fuel economy. These systems worked great on carbureted, high compression muscle cars when premium fuel became hard to get. Water injection doesn't give you more energy, it subtracts energy from the combustion process, limiting peak temperatures and allows you to run MBT spark if you run low octane fuel.