Tweaks have been made to the mapping of both engines following a Supercars study into the influence of inlet air temperature on performance.

That study, in part instigated by driver feedback, involved extensive testing on Supercars’ category dyno in Brisbane and revealed performances discrepancies.

Potential engine parity changes were the talk of the paddock on Thursday at Symmons Plains, with lingering uncertainty as to whether they would be enacted for the weekend.

A Supercars spokesperson confirmed to Speedcafe that they have now been signed off by the category and both homologation teams.

The outcome will be welcomed by the Ford teams and drivers who have continued to report being at a power disadvantage, especially when in traffic.

“As part of Supercars’ ongoing technical program, and through regular engagement with driver feedback, a detailed study was conducted into the influence of inlet air temperature on engine performance,” said the Supercars spokesperson.

“This investigation identified a variance in how inlet air temperature affects Ford and GM engines, specifically moving the power curves between the engines.

“It was found that temperatures below the nominal test temperature of 25°C slightly favoured the Ford engine, while temperatures above this temperature provided a minor advantage to the GM engine.

“In response to these findings, Supercars engaged MoTeC to develop an ECU software update, enabling engine calibrations to vary based on inlet air temperature.

“This software update has now been validated on the Supercars dynamometer and will be implemented for this weekend’s Tasmania round, with revised calibrations introduced to account for inlet air temperature variances.

“Both Homologation Teams have reviewed the test results and proposed calibration changes and have endorsed the rollout of the update.”

The changes effectively unlock one element of the double-overhead camshaft Ford engine’s Variable Cam Timing, which is strictly controlled by Supercars’ MoTeC software.

Supercars attempted to draw a line through the engine parity debate with testing on a transient dyno in the United States midway through 2024.

That followed wind tunnel testing in the US during the 2023/24 off-season intended to equalise the aerodynamics on the Mustang and Camaro body shapes.

However, performance has appeared to swing track to track; a situation that Supercars has repeatedly suggested is down to team performance rather than a parity issue.

Mustang drivers have won six of the nine races held so far this season, sweeping the weekends in Sydney and Taupo, while all three of Chevrolet’s wins came at Albert Park.

A trend of Mustangs qualifying well and falling back in races at some circuits could also potentially be explained by losing power with temperature.

Last year’s Symmons Plains event marked a relatively rare occurrence during the Gen3 era of both a Ford and a Chevrolet winning a race on the same weekend.

The engine temperature study is just one part of Supercars’ ongoing engine parity assessment, which includes a separate analysis on the impact of barometric pressure.