hi there, I use water to fuel a car as a supplement to gasoline. In fact, very little water is needed,only one quart of water provides over 1800 gallons of HHO gas which can literally last for months and significantly increase your car fuel efficiently, improve emissions quality, and save money. I found the way through this site http://carwaterguide.blogspot.com i really recommend it to everybody, it's a nice ebook where you can find the instructions on how to do it! take a look.