Link to free air density tuning info for drag racing at NHRA drag racing:
NTK NHRA Carolina Nationals, Oct 11-13, Concord, NC, 800-455-3267
Map location, air density, density altitude, grains, forecast, historic, & metric data "for good spark plug readings":
https://airdensityonline.com/track-r...otor_Speedway/
forecast:
https://airdensityonline.com/track-f...otor_Speedway/
historic (you can go back several years):
https://airdensityonline.com/track-h...ay/2019-10-09/