practical classics magazine did a test on one of these homemade kits in the june 2010 issue. i don't know if you can get it in your part of the world or not but anyway, their conclusion simply was that in order to get a 25 percent reduction in fuel economy using this system, the engine would have to run 42 percent leaner than usual, which a modern engine cant achieve due to lambda sensors, and the fact it will destroy the cat. in an ordinary, fuel injected car, it won't yield much in the way of fuel savings.
check out
www.sae.org and look for the following research papers on the subject: 841399 1984: Water/Fuel Mixtures,
740187 1974: Lean Burn With Hydrogen Supplementation (GM Corp),
810921 1981: Lean Burn With Hydrogen Supplementation (University of Michigan),
2004-01-1270: Hydrogen Reformate (H + CO2) (Robert Bosch GmbH),
760469 1976: Hydrogen Reformate in Aircraft Engines (Jet Propulsion Lab).
Apologies for the long winded post.
