Cadillac topped the timesheets in final practice for this weekend’s World Endurance Championship event at Austin.
Alex Lynn set a best time of 1m51.571s in the sole Ganassi-entered Cadillac V-Series.R to put the American marque at the front on its home turf, with Ferrari and Toyota finishing close behind in second and third respectively.
It didn’t take long for lap times to drop in the hour-long session at the Circuit of the Americas, as the mercury dropped from over 30C on Friday to 28.6C on Saturday morning.
Less than 10 minutes after the start of proceedings, Toyota driver Kamui Kobayashi had already bested the time set by Antonio Giovinazzi in the #51 Ferrari in FP2, going seventh tenths quicker on a 1m51.533s.
Giovinazzi responded in the #51 Ferrari on his next flying lap, but his 1m51.767s effort fell two more than tenths short of Kobayashi’s time.
Just a minute later, Lynn took to the top in his Cadillac, edging out Kobayashi’s time in the #7 Toyota by just 0.040s. His lap was not beaten in the remaining 45 minutes of the session, as teams switched their focus to longer runs at higher fuel levels.
Kobayashi dropped to third in the final order behind Antonio Fuoco in the best of the two factory Ferraris, the Italian getting down to within 0.040s of Lynn’s time after leaving his fastest lap until the end of first run.
Robert Kubica put the satellite AF Corse-entered #83 Ferrari 499P into fourth place with a mid-session lap of 1m51.534s, edging out the other works Toyota entry whose fastest lap was set by Sebastien Buemi.
The first five cars were separated by just 0.072s in what was an ultra-competitive session, as Cadillac, Ferrari and Toyota all looked almost undistinguishable over a single lap.
The fastest Porsche was the #12 customer Jota 963 in sixth, courtesy of an early effort of 1m51.712s by Norman Nato.
Giovinazzi ended up seventh in the #51 Ferrari, while Mick Schumacher put the #36 Alpine a solid eighth with a time that was just 0.324s down on Lynn’s best.
Julien Andlauer was ninth in the Proton Porsche ahead of 2009 Formula 1 champion Jenson Button in the #38 Jota, both drivers beating the two works 963 LMDh cars of Kevin Estre and Matt Campbell that finished 11th and 12th respectively — both being half a second off the pace.
Peugeot struggled to 14th and 16th respectively, while BMW had an even tougher session en route to 16th and 18th as they sandwiched the sole Lamborghini entry.
In LMGT3, Daniel Juncadella kept the TF Sport squad at the front with a late time of 2m05.178s in the #82 Corvette Z06.R, beating his own benchmark from Friday by four tenths of a second.
Charlie Eastwood made it a 1-2 for Corvette with a time that was 0.173s slower, while Davide Rigon ended up third in the #54 AF Corse Ferrari 296 GT3 on a 2m05.542s.
The late efforts from the trio dropped Gregoire Saucy in the #59 United Autosports McLaren 720S GT3 to fourth, while Alex Riberas finished fifth in the #27 Heart of Racing Aston Martin that had led a major chunk of the session following an early lap from bronze driver and team owner Ian James.
The final practice session of the weekend was completed without any major interruptions, save for a brief full-course yellow period with 20 minutes left on the clock to retrieve debris from the opening sector.