Free plans are available from http:h2o.localal.com

Do your research you see it's easy to build and hook up. I used a Dermal tool to cut the wall covers, different sides were cut so i could hook the wiring up with out shorting out on each other.

My hho generato only pulls about 19 amps, i get 30% increase in gas mileage with using any thing to ajust the o2 sensor or the map sensor. Increase in mileage at a time when gas is the cheapest it's been in years may not be a something you want to do. But it's the best time, you have more money  in your pocket with cheap gas. Now is the the time to build, learn before gas is $4.00 a gallon again, and it will be.