I built a cell for my truck ( 5.6L Titan) and I built another one with my neighbour for his toyota sequoia. He just went on a road trip and found he was normally getting 16mpgs highway. When he left with this cell installed he got a boost to 20-22mpgs. Nice little gain. He also found the higher in elevation he went(from florida with a 200 foot high spot) to PA ( closer to 1500 feet) he found he needed more NaOH to acheve the same amp draw. The cell we are working with pulls about 25 amps but I installed a live well pump to circulate water to the front of the vehicle and it helps keep it nice and cool (if anyone is having an overheating problem and would like me to post some pics of the setup, i will) So with all that said, my titan didnt see any boost in mpgs. And I was even doing more highway with it. It looked like It was getting better mpgs for the first half of the tank, but then when I filled it from empty I found I got 14.01 from my average 13.5-13.9. I do mostly city driving, not really much highway, so I really need to bring up my 13.5 mpgs to something more efficient. I am thinking of building smaller cells in series. Currently I have +nn-nn+nn-nn+ with an output of around .8 -1L/min. Normally thats ok, but I was looking around and found someone who put cells in series, it lowered his amp draw, while keeping his production up. Since I have a cooling system, I dont mind if I have 25 amps pulling, but if I can bring the amps down with multiple cells, boost the NaOH a little to bring amps up a little for more production, that would be ideal. Since I have a truck I am going to put the bigger cell in the bed instead of under the hood(due to little room) I am not running a PWM, and I dont really plan on putting one on. I would rather run it with constant power. I also do not have anything else done to o2 sensors or MAF sensor. Just injecting hydroxy into airbox on clean side of filter. Any thought or suggestions or brainstorming, bring it on.