[laynlo15]

Made a trip to the track yesterday, temps were about 82 and DA was 2750 or so on every pass. I know some have ask about Density Altitude and how it affects any car at the track. It slows our cars down in just about every case. The last time out a few weeks back on the same track temps were about 68 and DA was about 1450. My best pass then was 6.86@102 1.48 60 ft. My best pass yesterday was 7.03@100 w/1.54 60 ft. I still had some VP 109 in the car, but pulled some timing because I was warned about going to fast at that track. But, it was a tenth and a half slower and almost 3 mph. Track hooked great, just didn't have the power with the temps and da. I'd say the timing was a factor of 3-4 hundredths and the rest was the weather. I have my new METH kit that arrived Friday and I'll get that installed Wednesday as I'm trying to get ready for the Street Car Takerover in St Loius on the 27th. That way I can run it at full tilt at that race and not have to worry about getting kicked off the track.

[SGDM]

Damn skippy it makes a difference...

[DFW1LE]

How does DA get calculated at the track level, as it seems to be more of an aeronautical computation? Can one estimate the DA before leaving for a track session?

[steelheadrob]

Originally Posted by DFW1LE

How does DA get calculated at the track level, as it seems to be more of an aeronautical computation? Can one estimate the DA before leaving for a track session?

Here is a website that gives current and forecasted DA for different tracks.

https://airdensityonline.com/

[SGDM]

Originally Posted by DFW1LE

How does DA get calculated at the track level, as it seems to be more of an aeronautical computation? Can one estimate the DA before leaving for a track session?

There are several apps that you can use to calculate DA and as an aviator I use the local airport or my Kestrel, mini weather station.

[laynlo15]

I just look at my phone on drag times for Eddyville Raceway Park, Iowa. That's the highest temps and DA I've run in except at the Holley Fest last year at Bowing Green, Ky

[DFW1LE]

Thanks guys!

[laynlo15]

Anytime

[steelheadrob]

Anyone else notice a large difference between the DA shown on Airdensityonline vs Dragtimes? Just checked right now for my local track, Airdensityonline 2,648 vs Dragtimes 1,563. I typically use Airdensityonline because the track elevation on dragtimes is off for my local track by 400 feet. That explains 400 of the 1,000 DA difference but not sure what is causing the other 600 DA difference.

[SGDM]

Originally Posted by steelheadrob

Anyone else notice a large difference between the DA shown on Airdensityonline vs Dragtimes? Just checked right now for my local track, Airdensityonline 2,648 vs Dragtimes 1,563. I typically use Airdensityonline because the track elevation on dragtimes is off for my local track by 400 feet. That explains 400 of the 1,000 DA difference but not sure what is causing the other 600 DA difference.

That error is way too large. If there is an airport that is close you can check DA and PA, they are pretty accurate.

A number of factors (altitude/pressure, temperature and humidity) influence air density. A higher altitude, low pressure area, higher temperature and high humidity all have one result: they lower the density of the air. And as a result of that: a reduction in engine performance.

DA is PA corrected for temp, humidity, elevation. Thus ends the weather class...

[laynlo15]

Mine was Airdensityonline and not drag times. I just pulled it up on my phone. I have used the dragtimes in the past but couldn't get it to pull up yesterday. My error, my bad

[SGDM]

I would use airdensityonline, I compared several tracks with local airports and they were pretty close and Drag Times was over a 1000 ft off (higher) on all of them.

[ULTRAZLS1]

Got an app for my phone. autodens. it takes the da from the nearest airport.

[bybcous]

You gonna hang it up till fall at some point laynlow?