I recently purchased a so called "FUEL EXPANDER" it sounded too good to be true I was really skeptical but I bought it anyway, and installed it on my 1990 cavalier( it hooked into the fuel line and was placed on the radiator hose) I checked the mpg before it was installed it was getting 30 mpg . After installing the expander I rechecked the mpg the results were amazing the mpg increased from 30 to 48 mpg and I could tell a difference in the performance it seemed to have a little more pep. my question is how is it possible to get such an increase in mpg without losing horsepower? I am seriously thinking about putting one on my other vehicles seeing as how it worked so well on my Cavalier.