Brother Kurt Busch takes second in first of two sessions at Charlotte Motor Speedway
The Furniture Row Racing driver, one of 13 drivers competing for this year's Chase for the NASCAR Sprint Cup, posted a top speed of 190.759 mph. He had been second fastest in Saturday's opening practice.
Fellow Chase driver Kevin Harvick (Richard Childress Racing) was second in the nightcap, followed by NASCAR Sprint Cup Series champion Brad Keselowski (Penske Racing), and Chase drivers Clint Bowyer (Michael Waltrip Racing) and Kyle Busch (Joe Gibbs Racing).
Chase drivers dominated the opening practice, with seven of the top 10 speeds turned in by this year's title hopefuls.
Kyle Busch was quickest in the opening 55-minute session, posting a fast lap of 189.447 mph. Fifth in points, he will start Saturday night's Bank of America 500 from the No. 9 position.
Chase contender and Coors Light Pole winner Jeff Gordon (Hendrick Motorsports), was 10th in the final session after a top-five speed in the opener.
Keselowski and Juan Pablo Montoya (Earnhardt Ganassi Racing), neither among those in the Chase field, completed the top five.
Kevin Harvick, the No. 2 qualifier and last week's race winner at Kansas, had been 12th fastest earlier in the day.