Teams worked to understand the usual new car idiosyncrasies as they got on top of set-up and handling.
While doing so, extreme heat in the cabin proved a key talking point for drivers.
‘If I wiggle my toes, I'm touching the firewall'
“I'm struggling in the car, it's so, so hot,” van Gisbergen confessed.
“It's the hottest car I've driven in a long time – and they made us take all the heat stuff out last night that we put in, and then apparently it's going back in tonight or something.
“My feet are like, if I wiggle my toes, I'm touching the firewall,” he added.
“Last year they extended that cabin bit, so that cabin bit's further into the engine bay now.
“Yeah, crazy hot. Like, my feet are on fire.
“Hopefully they let us do something to fix it.”
Van Gisbergen not alone
Van Gisbergen wasn't the only one, with both Kostecki and Mostert also experiencing discomfort.
“Probably finding a few dramas getting in and out of the car more so, to be honest,” Kostecki said.
“There's been a few dramas around my feet but I haven't noticed probably as much as Shane.
“It's almost been a little bit better for us this year – so far we haven't done a race yet, following people, but you don't want to go into the race tomorrow with burnt feet because 24, 25 of us out there, we're not going to stop until we can't feel our feet.
“It's pretty obvious what happens after that.”
Calls for change
Mostert was the least affected of the three, though he agrees something needs to change.
“There's things that we should control and there's things that we shouldn't,” he reasoned.
“It definitely feels pretty warm to me out there today but, for me, it's like you sit in the pits the longest and the heat soak get in the car and it just doesn't quite cool, so as the session goes on for me it's getting hotter and hotter.
“There's no reason why we shouldn't be able to use as much heat shield as we can,” he added.
“At the end of the day, it's duty of care and the drivers should be protected the best they can.”
Supercars return to the Newcastle East circuit tomorrow for qualifying from 11:15 AEDT.