Scouder, yes, you can get the same or better miles per gallon as gasoline. It has already been tested and figured out. Starting in, 1902, I think. There was a time when there wasn't a gasoline station on every corner, and many differant fuels were looked at and tested. The reason we have petroleum based fuels everywhere now has nothing to do with them being 'better', because they aren't. Mr Ford originally tested his creations on ethanol, that was a very available fuel at the time. It is all about money, greed and corruption., The petroleum industry is just plain evil. We should be driving around on ethanol. It would be nice if that had been happening for the last 100 yrs, but we could get there yet, especially with oil at something close to 55$ per barrel. For some more recent MPG numbers for ethanol, check out the results for the 'Ethanol Vehicle Challenge'. About a dozen colleges have participated. They give the students a normal gasoline car (or truck ) and let them modify it. The winners have been able to get the same or better miles per gallon on ethanol as the unmodified car got on gasoline. So it is very do-able. They meet emission standards as well. I think Rusty has the right idea here, and if he builds with enough compression, I would run at least 12 to 1, I think he will do as well or better than he did on gasoline. DF