The two Corvette Racing drivers set the fastest time in class with 51.383 at the wheel of the factory #4 Corvette C7.R.
Dirk Muller and Joey Hand were second fastest with the #66 Ford GT from Ford Chip Ganassi Racing, their best time was 51.488.
Risi Competizione's Giancarlo Fisichella and Toni Vilander completed the top-three in GTLM with the #62 Ferrari 488 GTE.
Ford Chip Ganassi Racing's Richard Westbrook and Ryan Briscoe were fourth with the #67 Ford GT.
The BMW Team RLL run M6 GTLMs were fifth and sixth in class. Corvette Racing's #3 Corvette C7.R was seventh. Porsche North America pair of 911 RSRs were eighth and ninth.