Corrected vs uncorrected times

Discussion in 'OT Driven' started by insomnia, Aug 27, 2006.

  1. insomnia

    insomnia New Member

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    Just got back from the strip and ran the numbers through a calculator, do they seem low to anyone or somewhat close? I understand there will never be perfect conditions, I just want to see how much of an effect the weather is having :o

    Temp: 88°
    Humidity: 31%
    Track Altitude: 1250 feet
    Pressure: 29.76 in.


    Uncorrected = 14.509 @ 98.269

    Corrected = 13.84 @ 102.69

    Seem about right? :dunno:
     
  2. TriShield

    TriShield Super Moderator® Super Moderator

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    My car said the air temp was 83F.
     
  3. insomnia

    insomnia New Member

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    :dunno:

    The link on their site said 87, I added a degree since I got home about an hour after I ran last.

    With 83 degrees it would be a 13.91 @ 102.29
     
  4. RyeLou

    RyeLou OT Supporter

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    Seems right-ish.

    I do agree you can't really go on corrected times. I ran a 12.8 in +90% humidity and 93 degree weather and the corrected time was a 12.3 ish at like 4mph faster. I'd love to claim that though, haha. Actually I should beat both those times next time I get back. I've done quite a few things since and had a proper tune done.
     
  5. TriShield

    TriShield Super Moderator® Super Moderator

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    So as a rule of thumb corrected times aren't really accurate?
     
  6. RyeLou

    RyeLou OT Supporter

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    No that isn't what I meant. They are at least a good indicator of what would have happened with the exact same run at a different given altitude, but you can't go around saying you ran (insert corrected time here) You know what I mean?

    For instance, I ran a 12.8 something when I went at 112mph. There was a guy at the track rental with me that day who is a pretty serious bracket racer. He always brings this portable weather station that gives you pretty much everything. It gives temperature, humidity, barametric pressure, wind speed/direction, etc. etc. The important part is that it takes all of it and gives you a corrected air density altitude as well. The track we were at is roughly 780ft. above sea level. The correction for the weather conditions that day put the air density altitude at about 5,800ft. above sea level. The NHRA and a few other sites online have calculations and tables so you can figure out what you would have ran at a given altitude had things gone right. So on the day I went my timeslip says I ran a 12.8 @ 112, but the correction said a 12.3 @ 117 or something close to that. The correction is nice to keep your sanity as far as where you should be goes, but I can't go around saying I ran a 12.3 @ 117, not rightfully anyhow.

    I actually have a friend who makes almost identical numbers to me with the same car who lives in Denver, and their track is at about 6,000ft. above sea level. I asked him what his best time was at the track and he said it was a 12.6 I believe @ 114 or something around that. So the corrections do work, you just can't go around saying you ran that time (unless you explain all this to them)

    FYI here is a webpage with the calculations:
    http://www.smokemup.com/auto_math/nhra_correction_factors.php
     

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