Bu11dogg2
09-04-2008, 01:39 PM
1) Google Search the elevation of your track.
2) Go to www.wunderground.com (http://www.wunderground.com/) enter the city where your track is. Search the last ten years of reported weather. You'll want to get the temp, baro pressure, and dew point of the time and date of your run.
3) Go to http://wahiduddin.net/calc/calc_hp_dp.htm and input your numbers. Hit the calculate button and locate the calculated Density Altitude. The DA number generated is the calculated theoretical altitude during you run.
4) Take your DA number and apply to the NHRA correction factors table http://www.gnttype.org/techarea/misc/altitude.html
5) Calculate your numbers and that is what your car should have run under ideal conditions. Sometimes your DA actually shows NEGATIVE altitude which means the car is performing far better than normal and there's nothing to correct and compensate for. Usually only coastal areas in the South, East Coast, and Northeast will experience these rare conditions thanks to low altitude and strong high pressure areas due to the proximity of the ocean (~400 miles). It's also a primary reason most of the "freak" cars reside in these regions.
Enjoy!
2) Go to www.wunderground.com (http://www.wunderground.com/) enter the city where your track is. Search the last ten years of reported weather. You'll want to get the temp, baro pressure, and dew point of the time and date of your run.
3) Go to http://wahiduddin.net/calc/calc_hp_dp.htm and input your numbers. Hit the calculate button and locate the calculated Density Altitude. The DA number generated is the calculated theoretical altitude during you run.
4) Take your DA number and apply to the NHRA correction factors table http://www.gnttype.org/techarea/misc/altitude.html
5) Calculate your numbers and that is what your car should have run under ideal conditions. Sometimes your DA actually shows NEGATIVE altitude which means the car is performing far better than normal and there's nothing to correct and compensate for. Usually only coastal areas in the South, East Coast, and Northeast will experience these rare conditions thanks to low altitude and strong high pressure areas due to the proximity of the ocean (~400 miles). It's also a primary reason most of the "freak" cars reside in these regions.
Enjoy!