Yeah, it doesn't work. A professor at my University was helping a big local HHO company. A few of my buddies were going to try it out but the professor told them that while the company makes it look like a tiny HHO generator can give huge mpg gains, it really took up the entire trunk of the car. He went on to say that the gains achieved were directly proportional to the power it produced (ie they cut fuel by 20% and found they got 20% better mpg but lost 20% of the horsepower)