AZ does not change their clocks for DST. I believe clocks change on Nov. 4th this year for most places. According to the Manzy website racing begins on Thurs. at 6:30 PM, Friday at 6:30 PM, and Sat at 7:30 PM - all local AZ time.
The easiest way to determine what your location time of broadcast will be is to utilize
http://www.timeanddate.com . From this site you can determine your local GMT time zone and also that of where the event is being held.
Phoenix is GMT -7 and stays there since they do not change clocks. Just take the difference between your GMT time and that of Phoenix and you can determine your local start time. For instance NY is currently GMT -4 (3 hour difference to Phx), but after the clocks change, it goes to GMT -5 in NY and then there will only be a 2 hour difference to Phx.
Hope this helps.