I've heard of gains of 70% in milage, at cruise. True on the O2 in the exaust but they make an electronic box that basicly tricks the prossesor into thinking the O2s are running richer than they are to compensate for the O2 in the exaust. I'm trying to get the 316L together for a medium sized one like in the pic, stacked horizontally, for my carbed van right now. Dam thing gets 8-9 mpg. I have already built a very simple proof of concept, and it did every thing they said it would. Make sure you use a proper flashback arester and bubbler, the damb thing almost blew my hand off! The power of WATER! I use baking soda as electrolite because its safe and cheap, you don't really need it but efficency drops without it. The key is surface area. If you are making ALOT of gas, consider retarding the timing. Search this guy on the web, his patents are not to hard to find. To bad "they" killed him for his troubles.
projectcamelot.org/meyer.html
