St. Petersburg, Fla. – Sixteen-year-old Nate Stacy topped the charts in Thursday’s 50-minute GTS practice at the Pirelli World Challenge Cadillac Grand Prix of St. Petersburg. The session was held under sunny skies and 80-degree temperatures.

Early on GTS Championship Points leader Lawson Aschenbach, in the No. 10 Blackdog Speedshop Chevrolet Camaro Z28, topped the charts with a 1:20.570, followed by Jack Roush Jr., in the No. 60 Roush Performance Ford Mustang Boss 302, with a 1:21.235. Five-time Pirelli World Challenge Driver’s Champion Pierre Kleinubing, making his first appearance since 2010, slotted in to third on the charts with a 1:22.529 – Kleinbuing is piloting the No. 73 Compass360 Racing Audi TT RS.

At the 15-minute mark, Stacy, driving the No. 14 Roush Performance Ford Mustang Boss 302, slotted into third with a time of 1:22.193. Stacy’s teammate Roush Jr. then closed the gap on Aschenbach by posting a 1:20.888.

Aschenbach then improved on his fastest time by posting a 1:20.459.

Race Control then issued a red flag to remove a disabled car that was stopped on course.

The session went green again with 28 minutes remaining and Aschenbach reeled off a 1:20.407.

Roush then went to the top of the charts with a 1:20.262. PWC veteran Charles Espenlaub, making his first series appearance since 2010, then posted the third fastest time with a 1:21.742 – Espenlaub is piloting the No. 93 AK&J Sealants Maserati GranTurismo MC Trofeo. Brett Sandberg, driving the No. 13 ANSA Motorsports KTM X-Bow GT4, then slotted into third with a 1:20.942.

With 12 minutes left in the session, Aschenbach regained the top spot on the charts with a 1:20.100 only to have Roush Jr. post a 1:20.056. Stacy then topped the charts with five minutes remaining posting a 1:19.915.

When the checkered flew to end the session, Stacy’s fastest time held for top spot, with Roush Jr. second on the charts (1:20.056), Aschenbach third (1:20.100), Espenlaub fourth (1:20.471), and Sandberg fifth (1:20.609).

GTS drivers next take to the track for Round 3 qualifying this afternoon at 5:10 pm EST. Follow live timing and scoring at