Toyota’s six GR Supras largely languished towards the bottom of the timesheets on Saturday, with the notable exception of the #36 TOM’S car that was third-fastest in the hands of Sho Tsuboi.
Honda locked out the top two positions, led by the #16 ARTA car of Nirei Fukuzumi, while all four Nissan Zs finished inside the top eight, with Hiramine heading the manufacturer’s charge in fifth place aboard the #1 Team Impul car he shares with Bertrand Baguette.
This weekend’s Okayama test marks the first in which all cars are required to run the new carbon-neutral fuel (CNF) SUPER GT has adopted for the 2023 season.
All three GT500 manufacturers have struggled with a loss of power using the new fuel, with some estimates putting the straight line speed loss at 5-6km/h, but paddock speculation has pointed to Nissan being the least affected so far.
However, reigning champion Hiramine told Motorsport.com he thinks that, come the opening round at Okayama next month, Toyota will be right back in the mix.
Asked if he felt Nissan had the early advantage with the CNF, Hiramine replied: “This is not true. Honda are looking quite strong. And I think Toyota could be hiding something.
“I heard that Toyota is hiding some power. Every time in the results the Toyotas are quite low down, but I don’t believe they are really that slow.
“I believe at Round 1, Toyota will be fastest. Every year at Okayama, the #14 [Rookie Racing car of Kazuya Oshima and Kenta Yamashita] is fast. I am sure they are hiding something!
“I don’t know if it’s power, weight, but I think they could be hiding a lot.”
Hiramine’s best laptime of 1m18.276s was a little under half-a-second shy of the best effort posted by Fukuzumi in the two-hour morning session at Okayama.
While acknowledging the strength of Honda, especially the two-car ARTA team that has topped five of a possible seven test days so far this year, Hiramine believes Nissan should be able to close the gap as the weather gets warmer.
“Last year we struggled so much in the official Okayama test, the balance was so bad, but this time it looks like we can fight with Honda,” he said.
“Honda looks quite strong, especially in the first sector with the downforce corners. Especially in the cold season, they are so fast and I don’t think we can catch them. But now it’s getting warmer, it’s better for us.
“I don't think we have an advantage. Honda has improved a lot on the mechanical grip side compared to last year. But at the moment we’re looking good.”
