Competing in a time attack event at the Ipswich circuit on Thursday, Heimgartner clocked a 1:04.0378s lap behind the wheel of the 1000 horsepower plus MCA Suspension Nissan S13 Hammerhead world time attack car.
Click here to have your say on the state of Australian motorsport and go into the draw to win a Kincrome Tool Armour Workshop valued at $11,999.
The time was 0.03s faster than the benchmark set by Wills, although it is thought the time will not be classed as an official new outright lap record.
Heimgartner was testing the car for the first time ahead of a possible appearance at the World Time Attack Challenge event at Sydney in October.
“We knew the car was capable of doing some pretty fast lap times and I had it in the back of my mind that we could do it (go under the lap record),” Heimgartner told Speedcafe.com.
“I have had some lap records in class before but for the whole team and me to go under the lap record is something very special.
“It was awesome to drive something different, it has a lot of aero and 1150 horsepower, so it was definitely something different.”
The outing at Queensland Raceway followed a Supercars test day at Winton with Kelly Racing on Tuesday, where the team evaluated a new aero update ahead of next week's OTR SuperSprint at The Bend Motorsport Park.