Quote:
Originally Posted by jbsrace1
Density Altitude or DA is what effects ET. Temp, Hum & Baro psi are all factors that effect DA. The more one factor changes DA the more it will effect your ET.
On average a NA car on gas will change about .0053 in ET for every 100ft change in DA. To give you a example 70 deg, 80% hum & 28.9 baro psi = 2189.3 DA now say the temp go's up 80 deg, 80% hum & 28.9 baro = 2920.04 da
Back to 70 deg but hum jumps to 90% & 28.9 baro = 2222.02 da.
Where you see real big changes is in Baro psi.70 deg, 80% hum & 30.0 baro = 917.19 da and a fast day at the track 
Also wind plays a large roll. A typical door car will change +.03 with a 1-5 mph head wind and +.05 with a 6-10 mph head wind. And pick up about the same with a tail wind.
There are allot of other variables but that should give you ruff idea of how the weather effects your ET. |
Very Good Info.
So the Baro.Psi. is the most inportant factor ?
How do you get the DA using the temp.hum & Baro.? +,-,X,or divide ?
What is the formula ?
You are talking about 1/4Mi times ,right ? w/ .0053 in et per 100ft. change in DA
Thanks
