If you have to keep warming the motor to keep the temperature up, do it. If you want to go for the lower 16.27 E.T., be prepared to push the car around and sweat soaring engine temperatures. The situation is more complicated then this table because we are looking at only one variable-engine temperature. There are other things than variables to consider. The tactics, psychology, the need to make instant decisions under high pressure are part of the lure and a lot of the fun of bracket racing.
Lets go to the track.
Saturday night Your car sits for two hours in the staging lanes waiting to race. Engine temperature has dropped below 160 degrees. As darkness falls, the temperature drops to 81 degrees. It means that air density has increased so your engine will pull in more oxygen and make more power. You will go faster because you will make more horsepower.