The reason this technology gets bashed so much is that there are way to many scammers making huge exaggerations as to the performance and capabilities of these generators. These generators will not run the car exclusively on the gas they produce. What they will do is enhance the combustion of the fuel you are already burning which will increase efficiency. Because of this more efficient burn, the exhaust will contain additional oxygen which the O2 sensor will see telling the ECU that it's running lean and it will add fuel to compensate. You wire a circuit to the O2 sensor output that will offset it's voltage by about 100-200 mV which will tell the ECU that it needs to lean the mixture a bit. With these two mods significant gains are possible.
I didn't see the plans ever posted, maybe I missed them, but they are likely the same garbage that's floating all over the internet since someone mentioned the "coil" as part of the generator. If this is the "Hydrostar" or "HydroGen" or any other of the dozen variations of these plans for a water powered car they are bogus. I'm sure if you guys saw the electronics diagrams you'd see right away that they, for one, are not accurate. The generator itself is highly inefficient.
I have build several of these generators and my current model will produce approx. 1.2 liters/min of hydrogen/oxygen gas at only 10 amps and that's only running part of the generator. This is plenty of gas to make a difference in the combustion of the fuel and at a low enough amperage to not place a high load on the vehicles electrical system. Many of the systems being sold will claim 2, 3, 4, or more liters/min of gas and most are false claims. Some will produce decent amounts of gas but at 20+ amps which is just to much of a load and it will eat up any potential gains.