Lowndes fastest in V8 Supercar USA debut
The Holden Commodore driver stopped the clocks at 1 minute, 32.904 seconds in the final session of the day to become the first driver to get down into the "32s" for the Circuit of The Americas short course.
Ford's Will Davison was second fastest ahead of Holden Racing Team's Garth Tander. Techno Autosport driver Jonathan Webb bounced back from an spectacular engine failure earlier in the day to set the fourth fastest time in the final session of the day.
Earlier sessions today were led by Fabian Coulthard (Lockwood Racing), Scott McLaughlin (Fujitsu Racing GRM) and Shane van Gisbergen (TEKNO Team VIP).
"We spent three sessions redesigning the car a little, going up and down in spring rates but we ended up with a pretty happy balance," Lowndes said.
"In session four we were debating whether to run a second set of tires but we tried it and the car was really hooked up. I made a couple of little mistakes but we're still learning the track.
"The car was sensational on that second set. The way the tire hooks up here to the track is very different to what we've had in the past."
The 28 V8 Supercar teams will have two qualifying sessions and two races on both Saturday and Sunday – providing with plenty of action throughout the inaugural Austin 400 weekend.