Audi Sport Team WRT led the way in the first official practice for Saturday’s California 8 Hours.
The No. 10 Audi R8 LMS Evo of Dries Vanthoor laid down a 1:23.971 lap time in the 90-minute session, outpacing the No. 34 Walkenhorst BMW M6 GT3 by 0.271 seconds.
The Audi’s time was quickest of the weekend, besting Kelvin van der Linde’s pace-setting 1:23.982 set in the third and final test session on Thursday morning.
The pair of GruppeM-run Mercedes-AMG GT3s were third and fourth quickest, followed by the best of the Strakka Racing Mercedes, which completed the top-five overall.
All eight GT3 manufacturers were in the top-10, which was separated by less than eight-tenths.
The session saw two red flags, the first for an accident from the No. 35 KCMG Nissan GT-R NISMO GT3 of Josh Burdon, who drove the car back to the pits.
The lone GT Cup class entrant, the No. 88 ARC Bratislava Lamborghini Huracan Super Trofeo, stopped on track to bring out another red with less than ten minutes remaining in the session.
GT4, meanwhile, continued to be led by the No. 41 PF Racing Ford Mustang GT4.
Pre Qualifying is set for 3:05 p.m. PST.
RESULTS: Free Practice