Braun’s Acura topped the 90-minute session for the 34-car entry with a quickest time of 1m07.341s, over three quarters of a second clear of all rivals at the fabled sportscar track near Toronto.
Ricky Taylor’s Wayne Taylor Racing with Andretti Autosport Acura ARX-06 set the early benchmark at 1m09.803s. That was soon pipped by Alexander Sims in Action Express Racing’s Cadillac V-Series.R and then Augusto Farfus in the #24 BMW M Hybrid V8 – keen to make amends after his first-corner exit at Watkins Glen last time out.
Sims retook the top spot by 0.085s, as he worked down to 1m09.212s, but was quickly eclipsed by Tom Blomqvist’s Meyer Shank-run Acura, who dipped under the 1m08s barrier with 1m08.889s, 0.073s faster than Nick Yelloly in the #25 BMW.
Taylor then took P1 back with 1m08.568s, before Farfus produced 1m08.423s to go top, and Taylor then got within 0.011s.
With 20 minutes to go, Filipe Albuquerque took over the WTR Acura from Taylor and set 1m08.316s before Braun (in for Blomqvist) bested him in the MSR version by 0.043s with 1m08.273s. As Braun pitted, Albuquerque retook the top spot with 1m08.138s.
Pipo Derani (AXR Caddy) then entered the chat with a 1m08.121s, pipping Albuquerque for P1 by 0.017s before a red flag for an LMP3 car stopping on track.
The session went green with just four minutes remaining, and Braun unleashed 1m07.341s, putting him on top by 0.78s.
Derani was second, ahead of Albuquerque, Renger van der Zande (Chip Ganassi Racing Caddy), Farfus, Mathieu Jaminet (#6 Porsche Penske 963) and the sister 963 of Matt Campbell. Yelloly and Mike Rockenfeller (JDC Miller Porsche) rounded out the nine-car GTP field.
Garett Grist led the LMP3 field for Jr III Racing, ahead of Felipe Fraga (Riley) and Matthew Bell (AWA).
#12: Vasser Sullivan, Lexus RC F GT3, GTD: Aaron Telitz, Frankie Montecalvo
Photo by: Jake Galstad / Motorsport Images
Lexus leads McLaren, Corvette in GTD
In GTD, Alex Riberas led the early going with a lap of 1m16.925s in his Heart of Racing Aston Martin Vantage. Trent Hindman got to within 0.011s of that in his Wright Motorsports Porsche 911 GT3 R before co-driver Alan Brynjolfsson took over a spun at Turn 1.
Antonio Garcia reset the bar with 1m16.894s and then 1m16.724s in his Corvette C8.R to pull two tenths clear of the opposition.
But Frankie Montecalvo outdid the Spaniard, producing 1m16.558s in his #12 Vasser Sullivan Lexus RC F.
Frederik Schandorff was a surprise second in the #70 Inception McLaren 720S, ahead of Garcia and Ben Barnicoat in Lexus’s all-pro entry.
Second practice starts at 8:00am ET on Saturday.