Sean-
Please, do let us know how it goes witht he device, if/when you build it and install it. Lots of anecdotal here-say that some of these hydrogen or 'brown's gas' generators work. I might believe it for a 10-15 % boost...but when you get the 50% and 100% increases; it just seems implausible. We all know how inefficient our v-8s can be...even fuel injection doesnt help much. Increased performance and smooth idle has been scientifically proven to dramatically increase the weight of your right foot by 15-25% offsetting any fuel savings that the economy of EFI brings.
As more folks try these gizmos, I look forward to the feedback. I would guess that a slight leaning condition is being introduced --in an O2 sensor regulated system--and that this is where the 'economy' comes from...that a from a slight "steam cleaning" of the intake runners and such. This might lead to a slight increase in economy, but I dont expect anyone to see 100% increases. I have heard lots of second hand reports; "I have a friend in CO..." or "yeah, it works, this guy I used to work with built his own..." I would love to check one out, in person, go for a 50 mile drive with it off and the same 50 mile drive with it on and see what happens. Hell, I would pay for the gas.
Most of the "hypermiling" tricks work. I am getting a 20-30% increase just by driving like a grandma...but going from 10 to 13 mpg shouldnt be a stretch... a 5.0 should be able to get better...its a gearing, big tire, 4800 lb sitting 3.5 ft up in the air vehicle problem. Coast when you can, accelerate slow--except when you need to, and up shift as soon as you can. With the cams that most of us install for off-roading, they should cruise/pull fine from 1500 rpm (on the street). Its hard, however, to not want to goose it though. Driving as the common man's sport will definitely be on the decline in the future.