Subaru describes improvements to the updated 2023 BRZ

Subaru has revealed the 2023 version of its BRZ SUPER GT challenger, detailing changes made to the car in line with revised GT300 regulations for this season.

The Japanese marque held a launch and season changeover at Fuji Speedway on Tuesday, showing off the second-generation BRZ in a subtly revised livery for the car’s third season.

Drivers Takuto Iguchi and Hideki Yamauchi were on hand to put the car to the test as they aim to regain the title after being beaten by Kondo Racing Nissan last year.

Improving the aerodynamic performance of the BRZ has been a major focus for Subaru in the off-season, particularly as a result of the new GTA-GT300 regulations governing the floor and diffuser.

Team boss Masahiro Ozawa explained that while the new rules are set to make the BRZ more draggy by stipulating a top surface more akin to the car’s road-going counterpart, now the rear diffuser can be made bigger.

This is because the floor of the car now only needs to be flat to the frontmost point of the rear wheels, rather than to the centerline of the rear wheels, as was previously the case.

This means that the rear diffuser can start from further forward to increase rear downforce, in turn allowing the rear wing to be flatter to combat the increased drag created elsewhere.

Subaru also plans to introduce a revised front fascia for the start of the new season in April, although Tuesday’s facelift was carried out with the existing body configuration.

Ozawa also revealed that supplier BBS had developed new wheels for the new season, along with new tires from Dunlop.

“What determines the contact patch of the tire is the deformation,” he said. “However, if the wheel is deformed, this also has an impact on the contact patch.

“By increasing the stiffness of the wheels, it changes the way the tire touches the ground, as well as the distribution of tire heat.

“Since there are different stiffness characteristics in different directions, horizontal and vertical, we asked [the suppliers] so that everything fits on this side.

Also, a new ECU that had been tried before last season but was eventually shelved has now been properly introduced, coinciding with SUPER GT’s switch to carbon neutral fuel for this year.

“The new fuel we’ll be using this year has a slight tendency to not evaporate completely,” Ozawa said. “The residual fuel in the cylinder will mix with the [engine] oil, and this can cause the oil to become diluted.

“To prevent this from happening as much as possible, you need to precisely control the timing of the injection.”

The new ECU, which is mated to the same generation EJ20 turbo boxer four-cylinder engine that Subaru used in its World Rally cars in the 2000s, was in use during Tuesday’s overhaul.