My mileage in the sommer is around 26 to 29 mpg , in the winter its around 23 to 24 mpg depending on how cold it is , the average is 25 mpg , with the water4gas unit installed I got 34 mpg amazing , this was not highway driving backroads with hills stop and go and warm up in the morning when it cold ! In 2008 I've been skeptical, again, that triple the mileage can be achieved, until one of my readers, Gilbert B. from Missouri, USA, has tripled his truck's mileage from 7 MPG to 20 MPG . The only difference is that the Italian guy uses one device (small diesel engine), and the American guy uses six devices on his large diesel engine: The technology is simple, yet very effective: water is split into a SMALL amount hydrogen and oxygen ("HHO" or "Brown's Gas") and these gases are used to BOOST engine efficiency, thus saving fuel , cooling down the engine , while drastically reducing emissions ...the van was doing 14 miles on the express way with out the system and that in the city it definatly is less(lets say 12miles in the city per galon) well all these 360 miles were in the city with an average of 35 miles per hr. and only 12 miles out of these 360 were run with the air conditioning on. Giorgio Rossy from Italy boosted his Volkswagen turbo diesel's mileage by 77%, and Andres Rodriquez from Montana, USA, boosted his truck's mileage by 82% in the first week. I chose to read the Gas Savings Technique book first because this was the fastest way for me to start saving gas RIGHT NOW. This system is the best of the best and consists of the Electrolyzer (with the wiring harness, hoses and installation accessories), enhanced by the PCV Enhancer, Fuel Heater and above all MAP Sensor Enhancer or Electronic Fuel Injection Enhancer . HHO/BROWN'S GAS GENERATOR (people call it "Hydrogen Generator" but as I said HHO is more powerful than pure Hydrogen), consisting of the Electrolyzer, wiring harness, hoses and installation accessories. One of the biggest arguments to this technology is that "there's no such thing as free energy" and my response to that is I'm not getting any "free energy", I'm simply rearranging the potential energy already availible on my vehicle to improve overall efficiency. Water Car Run on WATER+Fuel. Hydrogen Save Gas=FREE ENERGY!