Sure seems to be a good indicator for my 1320 of whether it's gonna run hard or "so so" based on what I've seen to date. Never really paid any attention to it before starting this thread, either.

Is there an actual app for android phone ? I can go to web site on desktop computer , but not finding an app to place on my phone . I used to use dragrace workbench app but does not have all info needed . Gary

Wet air can be compensated for with timing. The biggest thing that will affect a naturally aspirated car is barometric pressure. As actual altitude goes up barometers go down. Also storm fronts can have a great affect on ACTUAL barometer readings. Not what you get on TV weather which is ALWAYS a corrected barometer reading. This is a big factor in calculating DA's. For instance where Brad runs his car the barometer is usually high 29's to over 30. Out here where I am we do back flips if the baro reading reaches 28.00! Why NHRA factors altitiude tracks and changes indexes for the various classes. Those only adjust for the physical altitude not the weather.

Al, would you expand on this please.

I think it's cuz water in the air/fuel mixture reduces detonation (aka water injection); if the water % in the air is higher, you should run more timing to help offset the reduction in O2.

Is that right, Al?

When it comes to barometric pressures the standard used in aviation is you lose one inch of pressure for every thousand feet of elevation above mean sea level, halfway between high and low tides.
High altitudes with high humidity and high air temps. really suck, huh Al
the bad thing about avaition weather reporting is they correct all of it to Instrument Standard atmosphere, which is 29.92 barometric pressure at mean sea level at 59.0 F with zero humidity
Las Vegas FAA reports for those airports around their will be corrected, not actual conditions, very misleading

If you can find your track on Air Density Online, it provides the actual as well as corrected (aka BS) barometric pressures, humidity, DA, water grains, etc.

The formula my prediction software uses is; DA, 1/2 baro, 1/2 humidity. If the 60ft is inputed correctly it will predict within a few .00x
Doug

Which part? As for grains of water(high humidity/dew point] you can advance to timing to "burn off" the excess water. Especially in lower gears where you have torque multiplication helping. We really see a very small drop off in performance when we go back east in "wet" air. But we add alot of timing to the engine to compensate. As much as 12 degrees in first gear 9 in second and 2-4 degrees above base timing in high gear minimum depending on the conditions.