Teams have just two test days this year, down from three, and both are to take place with the full field on track, rather than in private.

The field will test at Sydney Motorsport Park today ahead of the weekend’s season-opener, while a second test will take place directly after the Queensland Raceway round in August.

Among the revised testing regulations is a new rule stating: “The Primary Driver is not permitted to drive a Car outside of their nominated Team or Group.”

There was previously a provision for a primary driver to run a maximum of 10 laps with another team.

This was utilised by Triple Eight and its customer PremiAir Racing last season when Will Brown jumped into a Nulon Camaro at Queensland Raceway in May to provide setup feedback.

Other examples in recent years have also involved Triple Eight, which currently counts PremiAir, Matt Stone Racing, Brad Jones Racing and Team 18 among its data customers.

“I don’t understand what’s trying to be achieved there,” Triple Eight boss Jamie Whincup told Speedcafe when asked of the rule change.

“It was fine the way it was. If PremiAir wants Will Brown to do 10 laps in his car, then so be it.”

Everything you need to know about Supercars Sydney test

Teams are permitted to run nominated co-drivers during the two test days, as well as any additional drivers pre-approved by Supercars.

A host of squads are set to run co-drivers today alongside their primaries, with the majority having already locked down their line-ups.

The main focus for teams throughout the day, though, will be learning the new-for-2025 Dunlop control tyre, which teams have only had limited experience on during dedicated tyre tests last year.

Track running begins at 8:30am and concludes at 5pm. A 30-minute lunchbreak will take place from 12:30pm, after which teams can practice refuelling using the new fuel churns.

Stay tuned to Speedcafe for live updates throughout the day and the latest news reports from the circuit.