Yea the second day was rough on the ol body. And yes it's dirt track.
They water the track before the races. Alot of stuff can vary to cause the track to change over the course of the night starting with the the amount of water they put on it. The Wind an sun will also draw moisture out of the track. The amount of cars also. Everytime car goes around the track it will lay rubberdown from the tires. Normally during hot laps an qualifying the track is tacky l, which means u can hammer down and the big motors normally show out. trough out the night it will slick off an turn dry slick and motor don't matter as much, it's more in the driver throttle control and handling, and lap times can be a second or 2 slower depending on track, so this past Saturday it was like driving on ice, very dry slick and each week track is different never know what you may get, that's my best explanation