This video pretty much says it all.

[hunter]

For your 5.4 l v8 you need at least somewhere 8l/min to see some noticeable improvement. I have a v6 3.8 van, and I have two generators in. They make around 5l/min. and my gas millage went up from 22Miles/gal. to 28Miles/gal. and I haven't even installed my EFIE yet, only the O2 extenders. So don't say it's not working, you just need to make more HHO for that big monster.

[WilbyInebriated]

so you have put a way small generator in a WAY big vehicle for a day or two and you are already more than sure it will not work?  extra stress on the alternator? you driving around with the air conditioner on too?

[KilltheMessenger]

I live in Florida, and A/C is a must for me. I work in an office and I work for the power company, so the office is in the low 70's, while it is a humid 80 something outside. Plus I have allergies to most of what is outside. I think this happens to most of the people who transplant themselves to other parts of the country from where they were born and grew up..
In any case, I have to have A/C, and that that drags the mileage down a little, but all of my figures have been with A/C running. I could get above 21 MPG by just turning the A/C off, but not much higher. 
I have to check the draw on my current generator. The project is just now, catching up with the money I poured into it. The amp meters will be delivered tomorrow. My Fluke 87 will only measure up to 10 amps. I will either install the 30 amps meter I bought, or use the shunt with my fluke to increase its range.  I got the meter and shunt for less than one company wanted for the shunt alone. $10.95 for meter and shunt it pretty good.
If it will take a larger amount of HHO, I can take 1/2 of  the lower part of my tool box in the bed of my truck. That will be a very big generator. Making it run on under 15 amps will be a trick,  So tell me why I don't see any measurable increase in mileage from the HHo I feed my engine right now. Knowing a good reason for it, would make adding a lot more HHO easier to swallow.

so you have put a way small generator in a WAY big vehicle for a day or two and you are already more than sure it will not work?  extra stress on the alternator? you driving around with the air conditioner on too?

[WilbyInebriated]

so you drive a big ass truck to sit in an office? and you 'think' that you 'need' AC. wants and needs are two very different things. so let me be very specific. you don't 'need' AC. humanity has survived for thousands of years with out it. your convenience is the only thing that demands its use, however you choose to rationalize it. i have allergies also and its 90 and humid here but i still ride my bike instead of driving a big ass truck to sit in an office. there are lots of reasons why you are not seeing a mpg increase. a ICE is a complex machine. here's a thought, try scaling your motor down...

sorry if i sound a little harsh, i really have no patience for someone driving a truck to an office job with the AC on the whole way and complaining about mileage. on top of that you have clearly stated that you built the 'box' and placed this tech squarely inside said 'box' already. ie: "It simply can not work."

[KilltheMessenger]

This is about all the people that show everyone a little mason jar of a generator and try to make people think that it is saving them 20 to 40% in gas.  That simply can't work. if you can generate some huge amount of HHO and run a motor on it, that can work, and I never said it can not. Its the delicate balance between what is easily possible, and what you can do if you have a load of money, and a place to put that big ass generator. As for my station in life, I have nothing to applogize for. I'm not rich, but if I am better off than you, well, sorry.  yes, i do need the A/C, but if I should end of a poor jobless person and have to do without it, I may hang out in the mall instead.

so you drive a big ass truck to sit in an office? and you 'think' that you 'need' AC. wants and needs are two very different things. so let me be very specific. you don't 'need' AC. humanity has survived for thousands of years with out it. your convenience is the only thing that demands its use, however you choose to rationalize it. i have allergies also and its 90 and humid here but i still ride my bike instead of driving a big ass truck to sit in an office. there are lots of reasons why you are not seeing a mpg increase. a ICE is a complex machine. here's a thought, try scaling your motor down...

sorry if i sound a little harsh, i really have no patience for someone driving a truck to an office job with the AC on the whole way and complaining about mileage. on top of that you have clearly stated that you built the 'box' and placed this tech squarely inside said 'box' already. ie: "It simply can not work."