Both the Chevrolet Camaro and Ford Mustang have been subject to a number of tweaks as Supercars’ historic wind tunnel testing programme continues.

A race car from homologation teams Triple Eight Race Engineering (Chevrolet) and Dick Johnson Racing (Ford) have been sent to Windshear’s rolling road in North Carolina in a bid to finally settle the aerodynamic parity debate.

After the first of at least three days of activity in the Windshear tunnel was largely used to understand the traits of the cars as they were, the work teams in the United States began rolling through changes on the second 12-hour day.

UPDATE: Day 3 report: Supercars completes wind tunnel test

While tweaks to the Mustang were always expected, it was thought that the Camaro would be used as the benchmark, with its Blue Oval rival adjusted to suit.

However, a Supercars social media clip shows that the Camaro has also been going through several changes.

Vision shows a decklid boot spoiler being added, something which the Mustang had (in either of two specs) but the Camaro did not, as well as a rear wing position change.

DJR Chief Engineer/Ford Gen3 Chief Designer Perry Kapper was seen observing of said decklid piece, “It’s more like an extension,” with a voice off-camera responding, “Yeah, it is, yeah.”

There is also an expansion of the splitter edge which Jeromy Moore, Technical Director at Triple Eight, explained in said video as a means of addressing a pitch sensitivity issue.

“Just trying to improve the radius under the car,” he said.

“We found a big gain… Or, the Mustang found a big gain, going to our centreline profile on the front edge.

“Now we’re just trying to continue that, so we made a template to squeegee that all the way out.

“Our radius, our profile, dropped down towards the outside of the bumper, so we’re just trying to replicate.

“Trying to make the cars the same as possible. They found a gain so we’re just trying to improve that.

“It has an effect on pitch sensitivity, so proximity to the ground to make sure that the air can get under the car and not have a sharp edge where it stalls and chokes and you lose downforce.”

Pitch sensitivity was identified as an issue with the first aero package with which the Mustang raced, leading to a suite of changes effective the NTI Townsville 500.

Said changes were largely reversed when another new package was introduced for the Gold Coast 500 and Adelaide 500, across which Ford teams collectively swept the final four, 250km races of the year.

At Windshear, the Mustang was seen sporting new cheeks on its front bar – notable because the fog light bezel was reduced in depth by the second new aero package – and a different decklid spoiler.

From the Ford camp, Kapper said in the aforementioned social media video, “Essentially, [we are] just shifting the efficiency window of the vehicle so, basically, we power up the wheel band, and that allows us to essentially change the front downforce.

“Now we’re going to couple that with a change at the rear of the car.”

Downforce balance, front versus rear, had been raised as an issue for the Mustang during pre-season and again after racing began, with a stated reason for the second new aero package being to shift downforce towards the rear of the Ford.

Supercars General Manager of Motorsport Tim Edwards said that the cars were “very close” based on data observed from Day 1 in the wind tunnel.

The third day of activity continues now.