typical loss from 100deg heat and high elevation?
06-04-2006, 01:44 PM
#2
First you need to calculate your density altitude - so take the numbers you have, along with the barometer reading, and humidity.
http://wahiduddin.net/calc/calc_da_rh.htm
That will give you a number in feet. You can then go to a NHRA conversion chart and it will give you approximate correction factors for ET and MPH if you were at sea level. That can give you a decent picture of what your car would be running in better air.
For instance I raced last friday in 3000' DA, ran a 12.1@115, which corrects out to approximately 11.6@119 at sea level. I can't say I have a mid 11 second car, but at least I feel little better comparing it to other cars near me that run stellar times in mineshaft air.
http://wahiduddin.net/calc/calc_da_rh.htm
That will give you a number in feet. You can then go to a NHRA conversion chart and it will give you approximate correction factors for ET and MPH if you were at sea level. That can give you a decent picture of what your car would be running in better air.
For instance I raced last friday in 3000' DA, ran a 12.1@115, which corrects out to approximately 11.6@119 at sea level. I can't say I have a mid 11 second car, but at least I feel little better comparing it to other cars near me that run stellar times in mineshaft air.
06-06-2006, 03:45 PM
#3
http://www.modulardepot.com/density.php is a calculator I just found
I ran with assasin that night. His car at 5.5 psi of boost was running low 12's at 113 mph
My car at 12psi was running 11.8's @ 122 mph. While those times sound horrible the correction factor for our DA that night is pretty big even though the weather was pretty good. DA was only 4800', track is 2200 above sea level.
My corrected sea level times are 11.0 @ 130
BTW, there was ZERO track prep since it's a street night, 2.0-2.5 60's are normal unless on a slick.
I ran with assasin that night. His car at 5.5 psi of boost was running low 12's at 113 mph
My car at 12psi was running 11.8's @ 122 mph. While those times sound horrible the correction factor for our DA that night is pretty big even though the weather was pretty good. DA was only 4800', track is 2200 above sea level.
My corrected sea level times are 11.0 @ 130
BTW, there was ZERO track prep since it's a street night, 2.0-2.5 60's are normal unless on a slick.
06-06-2006, 06:44 PM
#4
thanks for that link, my corrected came out to 11.79@121, but w/my 2.0 60' times I know that will never happen on 5#'s... even on my drag radials I would normally get at least a 1.8 on my old car but it was just a spin fest that night...
06-06-2006, 10:05 PM
#5
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Just remember, corrected times can be just like converting 1/8-mile to 1/4-mile, not an exact science for every ride.
For example: My Nova has clicked off an 11.41 at 116 mph with a 1.520 60 foot in 500 DA air. Last time I raced a week ago, one pass in 2000 ft DA she ran an 11.56 at 115 mph. Rule of thumb is about a tenth for each 1000 ft of DA, but humidity, wind speed, air quality and track temps all take effect as well.
Derek
For example: My Nova has clicked off an 11.41 at 116 mph with a 1.520 60 foot in 500 DA air. Last time I raced a week ago, one pass in 2000 ft DA she ran an 11.56 at 115 mph. Rule of thumb is about a tenth for each 1000 ft of DA, but humidity, wind speed, air quality and track temps all take effect as well.
Derek