I know someone that tried this with a "commercial" device that was supposed to crack water into hydrogen. It ended up destroying his engine. He was a lucky little shit because his father worked at the Honda plant in Marysville and had a line on an engine from a car that had been in a transport wreck. The car was fine but written off, so it was parted out to dealers as "used." Brand new engine for nothing, the guys at the factory shop did the replacement.