I'm still intrigued by these HHO generators and the concept of using the car battery to fracture water to produce hydrogen fuel for a regular combustion engine. Apparently, it is nothing new. Here's a former NASA employee from the Philippines, Daniel Dingel, who invented this thing a long time ago. Check out his converted Toyota that runs on water! It's amazing.
I cannot find a technical reason why we're not driving these today. The only thing preventing it is political and/or entrenched economic interests.
Here's a better understanding of how water is being engineered in a negative energy vacuum inside the toroid (donut) coil with RF pulses to cause the hydrogen molecules to just fall off the hydroxy ion. The resulting hydroxy gas fuel is more powerful when burned than the power required to create it from regular tap water. This free source of energy is a gift from God. I think this is a huge leap forward in technology. I found a message board and a Yahoo Group on the topic.
You can get pre-built HHO generators for reasonable prices on Ebay. These would pay for themselves in just a few months.
I found another seller on Ebay, who sells smaller HHO generators of a different design, MAP sensor adjusters, and O2 sensor extenders (an alternative to an EFIE), so you can tweak the fuel mixture to get the best results. From what I've read, though, an EFIE is the best solution for adjusting the O2 sensor inputs into the car's computer to accommodate the new exhaust profile. He has some great tips in the text of his auctions, and the pricesare low.