Chaz Mostert was left “quite surprised” by his Practice 2 pace with the second quickest time at The Bend Motorsport Park.
The Mobil 1 Appliances Online Racing driver was 16th fastest in Practice 1 on a race run that saw him complete 20 laps of the West Circuit, the most of any driver.
Mostert ended the session 0.0920s shy of timesheet topper Scott McLaughlin in the leading Shell V-Power Racing Team entry.
Mostert said there is still more time to find heading into Qualifying for Race 28, which will comprise two knockout qualifying elements and a Top 15 Shootout.
The Walkinshaw Andretti United drivers said he was pleased with his practice pace.
“Obviously, last weekend the race car was disappointing for us as a team,” said Mostert, who recorded finishes of 11th, 11th, and 16th in the first weekend at The Bend.
“We’ve worked hard this week to come up with a different philosophy and work on the car.
“It’s taken a little bit to get the most out of it in myself at the moment, but I’m actually quite surprised to see it up there in practice.
“We’ve got some tuning to do. We’re still not quite happy with it, but we’ll keep pushing forward.”
Mostert’s fastest lap was set on his fifth tour of the 3.4 km long circuit.
The 28-year-old lamented a mistake on his final lap that saw him run well wide at the final corner and drop all four wheels into the dirt.
“(There was) just a little bit of frustration in that one,” Mostert explained.
“I didn’t quite have the tyre for the first half of the lap, so I was surprised to see the dash telling me that we were quicker.
“Practice is where you want to lay it all on the line. I had a big dip at the last corner, it had a bit of a snap on exit for me and it went along the grass.
“You’ve got to learn these things in practice.”
Qualifying for Race 28 gets underway at 12:55 local time/13:25 AEST.