On Thu, 11 Jun 1998 16:19:24 -0700 john pearson writes: >Is there some measurement of air that can reveal how well or >efficiently it >will combust or burn when mixed with gasoline vapor? The only component of air that reacts with gasoline is oxygen. So the number of oxygen atoms in your sample of air determines how much gasoline can be combined with it. Using enough gasoline to react with all the oxygen will release the most heat. Any more, and you're just wasting gasoline (and making a lot of black smoke, which is unburned carbon from the gasoline). It takes a long time for *all* the oxygen to react with gasoline, so the most efficient engine operation occurs when the gasoline ratio is considerably lower. Unless you can measure the oxygen content somehow, you'll have to assume the air is typical atmospheric air containing 21% oxygen. Then the amount of oxygen present in a given volume is related directly to the density. Density increases with lower temperature and higher pressure. This is why a turbocharger (higher pressure) and intercooler (lower temperature) increase performance. In the range of normal atmospheric pressure and temperature, the simple "ideal gas" equations are very close. Humidity is a minor factor at normal temperatures and pressures, but at high temperature and pressure any significant amount of water would change the thermodynamic properties of the air. Many garage alchemists proclaim amazing results from injecting water into the airstram entering an engine. I don't know if any more traditional scientific studies have been done. If there have been, the garage guys don't seem to be citing them, which suggest to me that the alchemist claims are just full of hot, wet, air. _____________________________________________________________________ You don't need to buy Internet access to use free Internet e-mail. Get completely free e-mail from Juno at http://www.juno.com Or call Juno at (800) 654-JUNO [654-5866]