Cadillac Whelen’s Jack Aitken set the fastest time in Friday morning’s first practice session for the Chevrolet Sports Car Classic in Detroit.
The red #31 Cadillac V-Series.R led Practice 1 with a best time of 1:07.254, set in the closing minutes of the 90-minute session. Renger van der Zande, in the 93 Acura Meyer Shank Racing ARX-06 was second-fastest with a 1:07.605.
Despite a recent Balance of Performance nerf, the #7 Porsche Penske Motorsport 963 still had enough one-lap pace in it to go third-quickest in the hands of GTP championship leader Nick Tandy. Tandy set a 1:07.651, within four-tenths of Aitken’s best.
Ricky Taylor in the #10 Wayne Taylor Racing Cadillac was fourth-quickest, followed by the two BMW M Team RLL Hybrid V8s of Sheldon van der Linde and Marco Wittmann.
As teams and drivers looked to approach the limit on the rough streets of downtown Detroit, 11 out of the 22 cars in the field slipped down into the runoff areas at least once.
Two of those cars were the #40 WTR Cadillac and the #9 Pfaff Motorsports Lamborghini Huracan GT3, which brought out a red flag after Louis Deletraz and Andrea Caldarelli went off simultaneously into the escape road at the end of Franklin Street.
Both cars were eventually able to continue with the rest of their session, but both cars will also lose their fastest lap in Qualifying later today for causing a red flag in practice.
The two Pratt Miller Motorsports Chevrolet Corvette Z06 GT3.Rs led the GTD PRO class. A string of fastest laps from the #3 Corvette of Alexander Sims put him at the top of the table with a 1:10.818.
He went two-tenths ahead of the sister #4 Corvette of Nicky Catsburg, who turned in a best lap of 1:11.009.
Marco Mapelli was third-fastest in the aforementioned #9 Pfaff Lamborghini, just a few thousandths up on championship leader Laurin Heinrich in the #77 AO Racing Porsche 911 GT3 R in fourth; Sebastian Priaulx in the #64 Ford Multimatic Motorsports Mustang GT3 rounded out the top five in GTD PRO.
Practice 2 begins at 11:30 AM ET (local time).
Feature image © Perry Farmer / IMSA
