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Discussion Starter · #1 · (Edited)
Anybody spend anytime correcting ET's?

I met a guy at Atco Tuesday (I wish I could remember his name to give him props) who turned me on to the calculator at Modular Depot.com
http://www.modulardepot.com/density.php

Most of the DA (Density Altitude) correction sites I had found in the past did not use Temp, Relative humidity and Barometric pressure, which is the data supplied on the timeslip (when they bother to turn on that feature).

He also told me there are some good weather history sites that can give some pretty accurate hour by hour weather data, for when they don't put it on the ticket.
http://www.wunderground.com/

Is one

Armed with that I went and corrected all the runs in my spreadsheet.

Interestingly, the run that stands out to me as being the biggest surprise is the first run I ever took in the car.

It was last July 10th at 6:21. On that night Cecil had the weather info right on the ticket temp 94, RH 42%, Barometer 29.42. Cecil's elevation is 320 ft. That works out to a DA of 3466 Feet.

That first run ever in the car, a [email protected] corrects to standard as a [email protected]!

Anyway, I corrected lots of runs, the vast majority come in around 11.7 @ 122-123.

Kind of makes the 11.944 from last night a little more palatable (Corrects to 11.65 @122.8)

JT
 

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The Ubiquitous Jimmy V.
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That's fun doing the correction for the summer runs..
Mine from last night:

Density Altitude = 3125 feet ET MPH
Uncorrected 12.05 @ 117.57
Corrected 11.6 @ 121.93
 

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Hey Guys,

How come when I go to wunderground.com I don't see any way to get historical weather data? Am I retarded?

MJ
 

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Discussion Starter · #4 ·
mjchip said:
Hey Guys,

How come when I go to wunderground.com I don't see any way to get historical weather data? Am I retarded?

MJ
It is hard to find, took me awhile.
Type in the zipcode you are looking for in that top box. When you get the forecast, about halfway down the page, right before the "nearby weather" starts, there is a place that says "Historical" . Use the pulldowns from there.

JT
 

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Discussion Starter · #5 ·
One thing I noticed when correcting. I think the corrected results are skewed a little because of 60 ft times. In the summer (+DA), traction is usually good, so when you correct a given summer slip, even though the car was down on power due to summer air, you still had enough power in the beginning of the track that you were traction limited, and not power limited. In other words the 60 ft time would not be any better if it was cooler. Actually, it may have been worse.

The opposite is true when correcting a slip from the fall (-DA), the first 60 ft may have been the same or better in the "corrected" enviroment, but the correction factor will make it worse.

Anyway, it still is fun correcting when the weather is crappy!

JT
 

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DAMMIT JT!!! This is NOT the way I wanted to get into the 11's..:(
 

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GREAT INFO. DO YOU NO WHAT WEATHER DOES IT CORRECT IT TOO.WHAT IS THE CORRECT STANDARD.
 

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JT,

Great info!! The weather history is awesome as most of my time slips do not have the weather info on them.

BTW - Thanks for the info to get me down to the 11.2's :D
 

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How much is your car off in the mph dept. in this shitty weather?
 

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Discussion Starter · #11 ·
Tuesday it ran 120.02, Wednesday 119.41. Had the IAT not gone wednesday, I think it would have hit 121. The 119.41 was the first run and the car was heat soaked from the drive there. I never let it cool, I was hotlapping until the IAT went.

JT
 

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Still very solid mph's for the heat!:cool:
 
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