Weather and performance

Jeff Lee · 06-10-2013, 11:38 AM

Having a weather station is crucial. Not only for ET prediction but to tell wether or not changes you make to the vehicle are positive or negative and weather is not skewing your results. It will also help with determining if your having me handicap issues.

Richard Grant · 06-10-2013, 05:40 PM

A tenth would not be unusual. a 1500 ft. of air change will move most gas cars a tenth. It's like a 20 degree temp change, a big moisture change or a big pressure change would have a similiar effect. On a race weekend it would be unusual to see a tenth change but from March to June in Louisiana would be a tenth or more of change. Going from 50 degree or so to 80,90, 100 degrees with the resulting moisture and pressure change could move a car 2 or three tenths. Dallas this year was very good air, close to zero or low hundreds. When the temps heat up the air density will rise to 3 or 4 thousand resulting in three tenths of et change.

joespanova · 06-10-2013, 05:48 PM

Thanks for the replies!

tj310 · 06-11-2013, 08:35 AM

This is the site I use * http://www.dragtimes.com/da-density-...e=Calculate+DA * I spent some time there and made up a sheet I refer to. ---Trevor

tj310 · 06-11-2013, 08:41 AM

http://www.usairnet.com/weather/maps...tric-pressure/ *air pressure map ---Trevor

1320racer · 06-11-2013, 08:42 AM

Joe, I/We have also seen upwards of a tenth difference in less than 1 day, racing Saturday and Sunday at the same track.

06-10-2013, 11:38 AM	#1
Jeff Lee VIP Member Join Date: Jul 2007 Location: Anthem, Arizona Posts: 2,766 Likes: 0 Liked 3 Times in 3 Posts	Re: Weather and performance Having a weather station is crucial. Not only for ET prediction but to tell wether or not changes you make to the vehicle are positive or negative and weather is not skewing your results. It will also help with determining if your having me handicap issues. __________________ Jeff Lee 7494 D/S '70 AMX Last edited by Jeff Lee; 06-10-2013 at 01:44 PM.

06-10-2013, 05:40 PM	#2
Richard Grant Member Join Date: Jan 2002 Location: West Monroe, La. Posts: 301 Likes: 9 Liked 13 Times in 7 Posts	Re: Weather and performance A tenth would not be unusual. a 1500 ft. of air change will move most gas cars a tenth. It's like a 20 degree temp change, a big moisture change or a big pressure change would have a similiar effect. On a race weekend it would be unusual to see a tenth change but from March to June in Louisiana would be a tenth or more of change. Going from 50 degree or so to 80,90, 100 degrees with the resulting moisture and pressure change could move a car 2 or three tenths. Dallas this year was very good air, close to zero or low hundreds. When the temps heat up the air density will rise to 3 or 4 thousand resulting in three tenths of et change. __________________ Richard Grant 4988 STK

06-10-2013, 05:48 PM	#3
joespanova Senior Member Join Date: Jun 2011 Location: Ga. Posts: 521 Likes: 7 Liked 13 Times in 11 Posts	Re: Weather and performance Thanks for the replies!

06-11-2013, 08:35 AM	#4
tj310 Member Join Date: Sep 2009 Location: Dresden On. Canada Posts: 460 Likes: 0 Liked 0 Times in 0 Posts	Re: Weather and performance This is the site I use * http://www.dragtimes.com/da-density-...e=Calculate+DA * I spent some time there and made up a sheet I refer to. ---Trevor

06-11-2013, 08:41 AM	#5
tj310 Member Join Date: Sep 2009 Location: Dresden On. Canada Posts: 460 Likes: 0 Liked 0 Times in 0 Posts	Re: Weather and performance http://www.usairnet.com/weather/maps...tric-pressure/ *air pressure map ---Trevor

06-11-2013, 08:42 AM	#6
1320racer VIP Member Join Date: Nov 2007 Location: New Jersey Posts: 2,628 Likes: 160 Liked 759 Times in 379 Posts	Re: Weather and performance Joe, I/We have also seen upwards of a tenth difference in less than 1 day, racing Saturday and Sunday at the same track.