CHARLOTTE, N.C. (AP) – This is the weekend that NASCAR conducts its Sprint All-Star Showdown and All-Star race. Tonight at Charlotte Motor Speedway it’ll be the Showdown, with the All-Star race taking place Saturday night. Both races at 7 p.m. The All-Star format has been tweaked for this year’s race. Drivers will run a pair of 50-lap segments with mandatory green-flag pit stops before a 13-lap run culminating in a $1 million prize. No driver has ever claimed first in a Sprint Showdown and gone on to win the All-Star event. Last year Greg Biffle and Clint Bowyer claimed Sprint Showdown wins while Denny Hamlin held off Kevin Harvick in the All-Star race. Hamlin will seek to join Davey Allison and Jimmie Johnson as the only drivers to win back-to-back All-Star races.