I work in a company that researches new fuel technologies. I have tested many fuel additives and even air ionizers. I have also charged the fuel electrically before it enters the engine. To make a long story short , none of the fuel additives will give you better gas mileage. You would think that fuel testing would be very simple, as many people think that they can do scientific experiments with their cars, but it isn't. Even with a strictly controled enviroment ( treated intake air,proper engine warm up, using exactly the same engine, multiple computers taking data) the data spread is still +/- 2%. Either people manipulate their data or they go to car trials to get whatever results that they want. Car based experiments do not work. I know it is hard to believe but they do not. In France they did a study involving over 1000 cars . Some of the cars used a 5% blend of Rape seed oil in their diesel. The conclusion was that the data was a mess and that there are too many variables on the road. If your fuel additive is quoting "real world" data from cars on the road then they are full of s$%t.