I have done some research and found a very detailed hydrogen booster plan that can be built from materials found at Lowes or Home Depot for as little as $100. You can expect between 15%-30% improvement in gas mileage depending on your vehicle. This .PDF file is huge and contains a few different plans. Find the plans that suit you best and make sure you understand how to overcome your fuel computer if need be. Its all there check it out, try it, post it, and ask questions. Have fun.

View boosterplans.pdf