I had built a megasquirt ECU for my old car, which is a totally custom home built stand alone engine management system so it was controlling everything from my spark angle to the fuel curves. I noticed that when my battery was low on voltage due to a faulty alternator my car ran super rich to the point of stalling just from flooding it. So when the voltage dropped my ECU made it run richer. With an OEM ECU in a car would it result the same when the voltage to the computer drops? The reason I ask at all is if the alternator has this additional load from the HHO cell will it reduce the actual voltage the car's ECU sees, possibly causing a loss of efficiency or richening the fuel curve? I wasn't sure if the battery will still have 13-14v even if the alternator cant keep up or not. It could be why some folks dont have as significant of gains. Possibly having a weaker alt could reduce the effectiveness?? Just thinking out loud!