[pgfpro]

Originally Posted by RustyLugNut

The Madyira paper does explain how the addition of 0.45% by volume of HHO at high power settings does result in an increase of CO due to the slight enriching effect of HHO. However, at the AFR ratios we ran the CB90 engine at ( 28:1 AFR ) there was no detectable change in the fuel mix ( one significant figure past the decimal ).

And you are correct, lean burn needs higher mixture energy to work well - cylinder pressure, cylinder heat and mixture energy ( kinetic energy in the form of swirl and tumble ). The Honda lean burn engines are optimized for this with high swirl heads, good compression and the use of large amounts of EGR. The Daihatsu engine was not a good candidate with it's low 8:1 compression ratio and relatively large overlap cam with much smaller volumes of EGR used. Thus, it's reluctance to run lean. However, with HHO as a crutch, the engine is easily able to run in lean burn. The engine was tested on a roller dynamometer under the front driven wheels of the Daihatsu. Power output was at 10 and 15 horsepower.

A forum member has built an engine that takes all the concepts of a good lean burn environment. Using a turbo that provides boost even at low throttle settings allows the buildup of heat, pressure and turbulence. He has a modern engine controller that allows him to control fuel and ignition with alacrity. He has run his car on the road at up to 30:1 AFR and somewhat beyond. Look for a build thread by pfgpro. It is highly revealing and entertaining.

I would love to do some HHO testing on my Talon. I just need to get the HHO equipment to do so.