Topic: Air Density Online

[Don R]

 There's a free source of air density altitude information especially if you are near a racetrack. I just looked up what it was around 3-4 pm at my nearest track when I was doing jetting test runs. Available in forecast, by the time  and in metric.
https://airdensityonline.com/tracks/?filter=222

[scottly]

Do Not use DA as a guide when jetting!! It is only useful as an ET prediction tool for dial-in at the drags, and then only when historical data of previous runs with different DA's are available. No amount of jetting will replace the lack of oxygen in "bad air".  

[Don R]

Do Not use DA as a guide when jetting!! It is only useful as an ET prediction tool for dial-in at the drags, and then only when historical data of previous runs with different DA's are available. No amount of jetting will replace the lack of oxygen in "bad air".  

You have been correct about everything carb related you have ever told me. My friend that races jr. dragsters picks his dial-in off of this web site. Not recommended but better than no data.  Since racers frequent this page I thought it might be of interest.
 I checked as a reference what to expect power wise when it's not cool and dense.  Today if it was jetted right (wasn't) it made more horsepower than it will most days when I'm riding.  Granted it was only seat of the pants, I'd prefer time slips but I missed that chance yesterday. 

[dragracer]

Do Not use DA as a guide when jetting!! It is only useful as an ET prediction tool for dial-in at the drags, and then only when historical data of previous runs with different DA's are available. No amount of jetting will replace the lack of oxygen in "bad air".  

You have been correct about everything carb related you have ever told me. My friend that races jr. dragsters picks his dial-in off of this web site. Not recommended but better than no data.  Since racers frequent this page I thought it might be of interest.
 I checked as a reference what to expect power wise when it's not cool and dense.  Today if it was jetted right (wasn't) it made more horsepower than it will most days when I'm riding.  Granted it was only seat of the pants, I'd prefer time slips but I missed that chance yesterday. 

I use that site when we're racing. It's helpful in lieu of a weather station/ET predictor. Definitely better than wetting your finger and sticking it up in the air.

[Don R]

  Some of my Super Comp buddies have weather stations running on a laptop that pages them in the lanes if the throttle stop number changes. Cha Ching$$

[dragracer]

  Some of my Super Comp buddies have weather stations running on a laptop that pages them in the lanes if the throttle stop number changes. Cha Ching$$

I have a brand new performaire Weather station that I've never used. I finally put it in the truck to start populating it at the Division 2 bracket finals race but neglected to use it then. Hopefully when I get to the Man Cup race, I can find time to finish setting it up. I really need to make some rounds if I want to finish in the top ten. That weather station could be my saving grace.

[Don R]

 We use crew chief pro on an old laptop to predict with a performaire. It's an older version. Somehow we got lost and while checking the history we accidentally made it update our ratio of air Density to ET according to what we ran and what it predicted. Previously we had to do that manually. By the end of the day it was agreeing with my guesses and the car. 
 As a rule we see .01 et for every 150 feet of density altitude.   A partly cloudy / sunny day makes it a little crazy.  On a day like that we dial quick and drive the stripe.