Joao Barbosa led an Action Express Racing Corvette DP 1-2 in the opening 90-minute TUDOR United SportsCar Championship practice for the Chevrolet Sports Car Classic.
After the team struggled on pace at the most recent round at Mazda Raceway Laguna Seca, the team was back on form in the first session of the day at the newly resurfaced 2.35-mile The Raceway on Belle Isle street circuit.
Barbosa, who will co-drive with Christian Fittipaldi in the No. 5 car, set a best time of 1:24.999.
The No. 31 car, driven by Eric Curran and Dane Cameron, was just behind at 1:25.041.
No other car was within seven tenths of a second. The two remaining Corvette DPs and the No. 01 Chip Ganassi Racing Riley-Ford completed the top five.
Renger van der Zande, who is pulling double duty this weekend between the TUDOR Championship and World Challenge, led Prototype Challenge at 1:27.668 in the No. 8 Starworks Motorsport Oreca FLM09.
Another double duty driver, James Davison, led GT Daytona in his No. 007 TRG-AMR Aston Martin V12 Vantage GT3 at 1:33.117.
The No. 23 Team Seattle/Alex Job Racing Porsche 911 GT America, No. 48 Paul Miller Racing Audi R8 LMS and No. 97 Turner Motorsport BMW Z4 GT3 made it four different manufacturers in the top four.
Two red flags flew, both to retrieve the No. 38 Performance Tech Motorsports Oreca FLM09.
The second 90-minute practice session runs from 1:15 to 2:45 p.m.
RESULTS: Practice 1