As revealed by Speedcafe last December, Supercars is reintroducing a formalised parity ‘trigger’ system this year as it welcomes Toyota to the mix alongside Ford and GM.

The structure of having a calculation based off in-race lap time data to trigger a parity review was abandoned after a politically-charged debut season for the Gen3 cars in 2023.

However, calls for its return followed two years of Supercars “constantly looking under every rug” trying to find individual technical discrepancies between the Mustang and Camaro.

While still a technical parity formula, the trigger system is intended to provide a solid structure to deal with any disparities in-season.

A first draft of the parity document was distributed to teams late last year, with a final distributed for feedback this week ahead of sign-off.

Supercars motorsport boss Tim Edwards told Speedcafe the system will be in place for the February 20-22 opener.

“Fundamentally the trigger system has been outlined and we’ll have a few smaller tweaks that we’ve been working on [following feedback], but they’re not major changes,” he said.

As per 2023, the basic premise of the system is that if discrepancies in the lap time data are sufficiently large to reach a set trigger point, a parity review will be undertaken.

Key to the new system is that adjustments can only be implemented during a season if the discrepancy is identified prior to the first endurance event.

“By the time we get to The Bend we’ve done 28 races,” Edwards said.

“The intention is that in 28 races, if there is any issues, it should have been flushed out by then. It’s a fairly decent sample size.

“We want to restrict making changes in what is the most critical part of the year, with Bathurst and then the Finals.

“It makes sense to everybody to use the 28 races to deal with any triggers, and if any happen in that last period we’ll address that for the new season.”

The provision is particularly pertinent given the introduction of the Finals Series that essentially wipes the points for the title contenders after the Enduro Cup.

Still, the fact the year’s two biggest prizes – the Bathurst 1000 and Grand Final – are stacked in the back end of the year has raised concerns over ‘sandbagging’.

A manufacturer could theoretically refrain from showing its hand in the early rounds in an attempt to time an adjustment ahead of the Enduro Cup.

Edwards, however, is confident the complex trigger system – involving a rolling calculation across multiple races and cars – is robust enough to deal with it.

“The way the system works, we believe it has protection in there for sandbagging, and it’s not based off one race,” he said.

He also pointed out the potential sponsorship pressure teams would face if deliberately tanking races.

“People talk about sandbagging, but there’s a fairly severe price to pay when you’ve got millions of dollars of backing for your car,” he said.

“Despite it being an easy philosophical thing to thrown around, the reality is the commercial implications of doing that can’t be discounted.

“Realistically, with what you’d have to do across multiple rounds and multiple cars, it’s very unlikely to happen.”

In-season parity changes in 2023 (pre-Gold Coast) and 2025 (pre-The Bend) were followed by signifiant swings in results.

Supercars is currently working through the Toyota engine homologation process ahead of the new season, with track testing to take place next week at Queensland Raceway and Bathurst next week.