if theres a thread just tell me to shut up but i couldnt find one. ive been hearing some talk about guys running 14.xx or whatever and deduct a certain about of time to due elevation, bar. pressure or something like that. that their time is actually faster than what showed up at the track. can someone clear this up for me please.

 

I am definately no expert on this but the higher you go (in elevation) the thinner the air gets,or less oxygen (closer to space).So... since a motor needs oxygen it would run better at sea level than in the mountains,and the air is more dense at lower elevations allowing more to go into the motor similar to a supercharger.

 

yeah i got that part, but ive seen people use their 1/4 time from their slip and calculate an "actual" 1/4 mile time. but i guess if im right at sea level or close i wont have to worry about that.

 

You should be fine...your in LA right? I think most of those corrections are for people up in the mountains like Reno and Denver, etc...

 

im in palm springs, but ill be at cal. speedway. thanks for the clear up.

 

If you do a google search for NHRA correction factors that should help. Barometric press., temp and humidity also matter alot.

 

sweet thanks

 

I think he is talking abour DA. Density Altitude.

 

Density altitude is based on 59 degrees Fahrenheit (15°C), with a pressure of 29.92 inches of mercury (1013mb) at sea level.

So if you are at a track thats at 1000' above sea level and its like 90 degrees out, the Density Altitude may be around 2000'. So the oxygen content is the same as it being 59 degrees but you being at 2000'.

The main reason for keeping track of these is one, to be able to compare times with people at other elevation tracks/weather...and also be able to compare your times throughout the season. This is huge in TX where you can run in the 40's in the winter but in the 100's in the summer. You could add a mod and have it look like you didn't gain any performance, but if you correct both times for their respective days DA then you get a true comparison.

If you have a track at sea level or close, it is easy to run in a negative DA which will usually produce the fastest times given you can get traction!

 

here's a good link

http://www.smokemup.com/tech/weather.php