SONOMA, Calif. — Mark Wilkins, of Toronto, Ont. posted the fastest time in Friday’s second 30-minute GTS practice at Sonoma Raceway, at the Pirelli World Challenge Grand Prix of Sonoma presented by Kia.

Weather conditions were 79 degrees under partly cloudy conditions.

Early on, Jack Baldwin, of Marietta, Ga., in the No. 73 GTSport Racing/Umphrey’s McGee Porsche Cayman S topped the charts with a 1:42.353, followed by Michael Cooper, of Syosset, N.Y. in the No. 10 Blackdog Speed Shop/Chevrolet Z28 with a 1:42.527, and Andy Lee, of Colorado Springs, Colo., in the No. 20 BestIT Racing/Chevrolet Camaro with a 1:43.445.

Cooper then went to the top of the charts witha 1:42.248. Then Wilkins, in the No. 38 PutOnTheBrakes.Org/KIA Optima posted the fastest time of the session with a 1:41.874.

Race Control issued a red flag 20 minutes into session as the No. 35 Calvert Dynamics/Phoenix Performance/Ford Mustang Boss 302S of Preston Calvert, of Potomac, Md., suffered a mechanical issue and sat wounded in turn 5. Safety crews removed the No. 35 car and the practice session resumed with just over two minutes remaining.

Wilkins’ time stood when the checkered flew to end the session. Cooper’s time held for second fastest on the charts. Ben Clucas, of Northampton, England, in the No. 36 DonorsChoose.org/Kia Optima posted the third quickest time with a 1:42.335

GTS drivers now get set for Round 16 qualifying scheduled for Saturday at 9:55 a.m. Pacific. Follow live timing and scoring at http://worldchallenge.growsites.net/