Last time at the track I was talking to some folks that do a LOT of bracket racing and have been doing it for many years. They are never more than .001 or .002 off thier dial. After they watched me break out in the second round, we started discussing weather stations and computer programs. I told them I was thinking about getting the Crew Chief Pro program this winter. They told me that they have had 3 different programs, including Crew Chief and they don't use any of them anymore. They figure it all by hand. He told me to look in the front of the Jeg's log book and it explains ratios. He did'nt tell me whether he uses one ratio or a combination of all of them? There is Corrected Altitude, Humidity, and Wind Speed. What's the difference between Corrected altitude and Density altitude? I'm guessing that corrected altitide is some of these other factors put together? It does'nt make sense to me to use a corrected altitude ratio along with a humidity ratio? Can someone please expain this stuff to me? (remember, I'm NOT a calculus major!) Thanks!