I have found that not alot of people know how DA works and how it can affect your times at the track so I will post some links here so you guys can arm yourselves with a lil more knowledge so maybe in bad weather you dont come home bummed like I usually do

When we think of good track conditions most people only think about Temps, some calculate in humidity, but we also have to figure in barometric pressure to get the full picture. All of these three things combined will determine the density of of oxygen in a particular unit of air entering your motor. So in effect it can make it seem like you are higher or lower elevations that what you are truely running at. So in essence, if your track is at sea level and you have a very good DA day then you could effectively be racing at -2000+ft below sea level!! or on a crappy day be 2000+ feet above sea level

The first site is a weather board and if you find the city/town closest to your drag strip you can do a history search and pull up weather data for whatever day you were at the track even if it was a year ago. For best results try to get the weather data directly from the track.

Weather Site

Now you can take your gathered data and input it at this site and come up with your effective DA for all your runs. The important thing to consider is that since weather is dynamic so are the conditions for each of your runs. So for best results check your timeslips for a time and match it up to the weather report data. It sounds complicated but is quite simple and can go a long ways toward tuning the car/truck and keeping tempers down

Density Altitude Calculator

 

Cool, thanks!
Jim

 

Hey F8LPONY! I did a check this morning and inputted the data from when I ran my best of 14.85 on 4/16/03 to the day we were there, 5/28/03. On 4/16 the temp was 57*, DP 48* and barometric press, was 29.98", the DA was 580 ft. When we were there and my last run was a 15.02 is was 98*, DP of 48* ans BP of 29.77", the DA was 3380 ft. What a difference!
Jim

 

Hear at sac on a Decent night it is often up to 300-500 feet below sea leavl

 

LOL

I figured as much Jim, that is one of the reasons I posted it. I figured even if no one else cared about DA you would

Now, like Brandond stated above, Imagine how nice it would be to run on one of those really cold, low humidity days in the late fall when the DA is -1000ft or more