http://www.mickeythompsontires.com/tech.php?bulletin=s1"BURNOUTS- FOR MOST APPLICATIONS
The length of your burnout will be dictated primarily by the ambient and track conditions. The hotter the temperatures, the shorter the burnout. When the temps get cool, a longer burnout will be necessary. Ideally you want the tire temp to be within 15 degrees of the track temperature on the launch. When the track temps exceed 120 degrees, it is always best to keep your tire temps on the lower side. Here are some additional tips for maximizing the performance of your M/T racing tires.
1. First pass of the day will be your longest. After that follow the guidelines of #2 and #3 stated below.
2. Automatic transmissions and Bias tires with Softer compounds: First pass or two, fairly hard burnout relative to ambient conditions. After that a light burnout should be sufficient.
3. Standard transmission and Radial tires: Typically shorter burnouts are better. A light burnout, enough to haze the tires, then stage immediately.
4. No dry hops. This does nothing to improve traction, and in some cases can have a negative effect."