Matt Plumb set the pace during the first day of Continental Tire SportsCar Challenge action at Road Atlanta on Thursday in his C360R McLaren 570S GT4.
A lap time of 1:28.879 set by Plumb in the first session was unbeaten in Thursday afternoon’s second session, during which Jack Roush Jr. was quickest.
The KohR Motorsports driver posted a time of 1:29.283 in his No. 59 Ford Mustang GT4 while Plumb’s co-driver Paul Holton was second by two-tenths.
The second-fastest driver of the day was Roush’s teammate Scott Maxwell who was second in Practice 1 in the No. 59 Ford.
Guy Cosmo was third in the morning session in the No. 4 Team TGM Porsche Cayman GT4 Clubsport MR.
In Street Tuner, the CRG-I Do Borrow Nissan Altima was fastest in both sessions, with Owen Trinkler setting the pace both times.
His best time of the day was a 1:35.416 in the morning session, before going eight-tenths slower in the afternoon.
Mat Pombo was second in the morning driving his No. 73 MINI JCW while Christopher Stone was second later in the day in his Murillo Racing Mazda MX-5.
The No. 65 Murillo Porsche Cayman with Tim Probert at the wheel went off track late in the afternoon session, causing the red flag to be brought out for three minutes although the Texan was able to drive back to the pits.
A short 20-minute practice session kicks off Friday’s action at 8 a.m. ahead of qualifying at 8:30 a.m.