Most definitely a hoax, don't waste your time even looking at this or
similar bogus web sites. What it is, is a lame variation of a contraption
that WWII pilots used to enhance flight mileage. First of all, it relies on
a mixture of water and an acetone mixture that must be maintained to a
proper mixture at all times to work. Second, acetone, not good for your
engine sensors and great if you get it on your paint. Third, this may or may
not have worked on old-school technology planes, you are driving a modern
car with lots of electronics and sensors, octane was much higher than today
especially for planes. You are driving a Saturn not a 1943 P51 Mustang.
Definitely full of balonium.