SUPER GT: Subaru outlines improvements on updated 2023 BRZ

The Japanese marque conducted a season launch and shakedown 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 through its paces as they aim to regain the title following their narrow defeat by the Kondo Racing Nissan squad last year.

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

Team boss Masahiro Ozawa explained that, while the new rules are set to make the BRZ more draggy by stipulating an upper surface more similar to the car's road-going counterpart, the rear diffuser can now be made larger.

That's because the underfloor of the car now only has to be flat as far as the front-most point of the rear wheels, rather than until the centre line of the rear wheels, as had been the case previously.

This means the rear diffuser can start from further forwards to increase rear downforce - in turn allowing the rear wing to be made more flat in a bid to combat the increase drag created elsewhere.

In addition, Subaru is planning to introduce a revised front fascia for the start of the new season in April, although Tuesday's shakedown was undertaken with the existing bodywork configuration.

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

#61 SUBARU BRZ R&D SPORT

Photo by: Motorsport.com / Japan

"What determines the contact patch of the tyre is deformation," he said. "However, if the wheel deforms, this also has an impact on the contact patch.

"By increasing the rigidity of the wheels, the way the tyre touches the ground changes, as well as the heat distribution of the tyres.

"Since there are different rigidity characteristics in different directions, horizontal and vertical, we asked [the suppliers] for everything to fit together on that side.

Additionally, a new ECU that had been trialled ahead of last season but was ultimately shelved has now been properly introduced to coincide with SUPER GT's switch to carbon-neutral fuel for this year.

"The new fuel we will be using this year has a slight tendency to not evaporate fully," said Ozawa. "Residual fuel in the cylinder will mix with the [engine] oil, and this can cause the oil to become diluted.

"In order to prevent this from happening as much as possible, it's necessary to accurately control the injection timing."

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