mdvaldosta

[b]So you claim you got a slow time because it was hot and humid? You think your car is faster than what it ran? Someone else posts that their car ran faster than yours with less mods? There is a formula developed by the NHRA to level the playing field for 1/4 mile timeslips - it uses your density altitude and a correction chart to determine what you would run under ideal conditions. So you wanna know your corrected time huh?

Well, here is how to calculate it:[b]

*Click here to look up the weather information like temp, bar pressure, & elevation. You will need to click here to determine your humidity using info from the first link. (if anyone can find a place to find all this together that would be great)
*Click here for a calculator to determine your density altitude.
*Now that you have your DA (density altitude) you can look up the correction factors here.

Thats it. Simple enough. Lets go over an example just to be sure.

On May 20th, 2004 I ran a 13.58 @ 102.05 mph at my local track. Using the links found above I calculate that my DA was 1953 feet, and I will round that to 2000 feet. Using the conversion chart linked above I see that the correction was .9770 for time and 1.0241 for speed. A little 3rd grade multiplication gets my DA corrected times to: 13.27 @ 104.51 mph.

So, now you can never blame weather for your crappy times, you can convert your timeslip to standard and now compare your times to what you may have run a few months ago in the cooler weather, or with people in other parts of the country at different altitudes and temperatures - no more "what if's". Also remeber that I believe that there are different correction NHRA correction factors for different tracks and using a power adder like a supercharger may change your correction factor.

mdvaldosta

bump, don't want all my time writing this to go to waste...

jdaniel

I did mine and I run an average of 13.6 to a 13.9 LOL thats using several different times I run. Good info MD.

Dan04COBRA

It's pretty cool to have, but what about us who ran quick times or crappy times a couple weeks ago and can't get that weather information anymore

Just thought I'd ask that question for everyone...

bossman351

Can you use it for 1/8th mile or 1000 ft??

matthockey32

yeah, i like the corrected numbers a lot. so that is what i should run under ideal weather.

mdvaldosta

the link I posted for the weather info shows to go back to 1973, I personally went back a month to find mine.

not only ideal weather, but ideal altitude. the farther you race above sea level, the slower you run. the DA correction factors in not only what you would run in good weather, but also if you made that run at sea level. So, its likely that unless you live close to sea level you won't ever be able to run the corrected times you get using DA - but it serves its purpose - so that you can take someone who lives in the mountains in the summer and compare it to someone who ran in Florida in the winter.

RJM02GTDrag

MD whats with the 2.0 60 foot? You must have a 12 second car if you can hook?

formula87350

This is lookin' pretty good! I got a DA of 6691, but the last link isn't working! I will keep you posted so I can move up on that damn list.

Alright I got the link to work but it only goes up to 6000. Using the 6000 DA I got an E.T. of 13.0499 @ 109.92. So that is a lot better than that damn 14.1!

98LS1

Haha! That's awesome Joe. My corrected time was 8.4 @ 85mph. That's great. I wonder what my corrected hp numbers are....

I can't believe I just seen this.