To answer your question indirectly, it would take HUNDREDS of amps continuously pumped into the 'electrolysis bucket' to produce enough H2 and O2 to get your engine to even idle independent of gasoline. Those gimmicky setups they are trying to sell you produce a few liters of H2 and O2 per hour. A few LITERS per HOUR. Keep in mind most of us have engines that can consume 5 liters if air in two revolutions. At 2000rpm, that's potentially 300,000 liters per hour under full load, and closer to 50,000 liters per hour at a normal highway cruise load. That 50,000 liters of air is 20% oxygen, so your electrolysis bucket would only have to produce a mere 10,000 liters per hour to completely replace the gasoline. Producing 100 liters per hour (more than any gimmicky kit you can buy) will contribute to 1% of the energy your engine is consuming, thus improving mileage 1%. To produce enough H2 and O2 to even make a DENT in the fuel consumption, it would drain a car battery in minutes, especially considering the efficiency of electrolysis of water is around 50-80%. Combine that with the ~30% thermal efficiency of the internal combustion engine, and you'd be way ahead of the game to just directly power an electric motor.

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'86 Bronco, 460, E4OD; '85 Ranger, 350hp 289, T5, 13.2@105.2
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