At the wheel of the factory #3 Corvette C7.R, Antonio Garcia set the quickest time overall,1:42.623.
As was the case in the opening practice session, Ford Chip Ganassi Racing's Joey Hand and Dirk Mueller were second fastest with the #66 Ford GT, just 0.077 seconds behind the Corvette best time.
Their team-mates Richard Westbrook and Ryan Briscoe completed the top-three sharing the #67 Ford GT.
Risi Competizione was fourth fastest with the #62 Ferrari 488 GTE of Giancarlo Fisichella and Toni Vilander. The car had a crash halfway through the session with Toni Vilander behind the wheel.
The BMW Team RLL #100 BMW M6 GTLM was fifth. The Corvette Racing #4 Corvette C7.R was sixth. The Porsche North America #912 Porsche 911 RSR was seventh. The BMW Team RLL #25 BMW M6 GTLM was eighth. The Porsche North America #911 Porsche 911 RSR was ninth.
IMSA GT Le Mans and GT Daytona teams will be back on track on Saturday for a third and final practice session followed by the qualifying one.