How does air temperature and track temperature effect a Nascars handling on a track?

May be...

The air temp effects how the engine runs and how much tape they
out on the front nose of the car witch effects the areo dinamits of the car .
The track temp effects how well the tires will stick to the track. They will run different tires depending on track temp.

Track temperature affects the tires,
ambient temperature affects the induction, and shock pressure
(just a couple of the basics)

Air Temp.>
It has a big effect on Horsepower (cooler air means that its more dense which means more oxygen that will fit into the cylinder and that allows you to richin the mixture which will result in more horsepower) and all around engine performance, cooler is always better. Heres a free tool that I have used> http://www.anycalculator.com/enginehorse...

Track Temp.>
Knowing the temperature of the track is important, but one cannot rely on this measurement alone. Crewmembers are always seen walking the starting line in order to get a feel for track conditions. I use the ball of my foot to gauge track conditions. Putting most of my body weight on the ball of one foot and trying to pivot gives me a really good indication of what kind of traction I can expect. Here's how to tell what kind of track conditions are present before a run:

Too hot: A hot track tends to be very slippery. As the track gets hotter, the rubber on the track becomes gummy. When checking the groove with the ball of the foot, if the track is too hot (greater than 115 degrees Fahrenheit), the foot will twist easily and leave marks in the rubber on the track. The groove will also be mushy, like bubble gum. Needless to say, this is not good for traction. Hot tracks also tend to have more bald spots, which further hinder traction on the starting line.

Too cold: In some cases, a track that is cool can be good; however, generally speaking, if the track temperature is cold (between 50 and 60 F), the track may not have enough adhesion. Under these conditions, the rubber on the track will be tight, but when trying to pivot the foot, it will turn fairly easily.

Just right: For traction compounds to work properly, the ideal track temperature is between 70-85 F. Under these conditions, the rubber on the track will be tight and have good traction. When checking the groove, the foot will twist slightly and the rubber will be firm and tight. This is the ideal condition and will give maximum traction.

the hotter the slickerkipper stuffed