As per the opening day of the test, Sho Tsuboi set the best time at the wheel of the au-branded TOM'S GR Supra during the two-hour morning session, marginally improving on his Saturday benchmark with a 1m18.116s.
That was enough to beat the best of the all-new Nissan Zs, the #23 NISMO car of Tsugio Matsuda, by 0.130s.
Matsuda had briefly put the #23 car at the top of the times with his effort of 1m28.246s before it was eclipsed by Tsuboi, improving on his best time from Saturday by almost half a second.
Katsumasa Chiyo made it two NISMO-run Zs inside the top three aboard the #3 NDDP Racing car, albeit fractionally slower than the best time his new teammate Mitsunori Takaboshi did on the opening day.
Chiyo was also involved in a collision with the #88 JLOC Lamborghini of Takashi Kogure at Turn 2 that caused the third and final red flag of an incident-packed morning session, although the #3 car escaped with only minor damage and was able to continue running thereafter.
Fourth-fastest was the #37 TOM'S Toyota of Ritomo Miyata, narrowly ahead of the best of the new-look Honda NSX-GT Type S machines, the #100 Team Kunimitsu car of Tadasuke Makino and Yuichi Nakayama in the SARD Toyota.
Nakayama's new teammate Yuhi Sekiguchi caused the day's second red flag with an off at Turn 1, although the car was able to return to the pits unaided once retrieved from the gravel trap.
The majority of GT500 teams did not improve on their Saturday laptimes on Sunday, but the two Yokohama-shod cars proved an exception, with the Kondo Nissan going eighth ahead of the Racing Project Bandoh Toyota in ninth.
Race simulations were the order of the day in the afternoon session, which began with a practice race start. Nobuharu Matsushita set the pace on a 1m19.361s, making the #17 Real Racing Honda the only car to improve in the afternoon, 0.058s ahead of Impul Nissan driver Bertrand Baguette.
GT300: Saitama Toyopet Supra the car to beat
Saitama Toyopet's Toyota GR Supra was the pacesetter in the GT300 class, with Kohta Kawaai setting the best time of the day in the morning of 1m25.917s.
That was however some seven tenths slower than the benchmark established by Kogure and the JLOC Lamborghini squad on Saturday.
The top four times overall for the day were set in the morning. Behind Kawaai, next up was Kei Cozzolino in the Pacific CarGuy Racing Ferrari 488 GT3, Naoya Gamou in the LEON Racing Mercedes-AMG GT3 and Takashi Kobayashi in the UpGarage Honda NSX GT3.
Fifth overall and setting the pace in the afternoon was Joao Paulo de Oliveira in the Kondo Racing Nissan GT-R NISMO GT3.
De Oliveira's best time was a 1m26.464s, while the #88 Lamborghini was second in the afternoon and 10th for the day in the hands of Yuya Motojima.
Defending class champions Subaru sat out the afternoon session following a crash for the BRZ during the morning while Hideki Yamauchi was at the wheel, which caused the day's first red flag.
The afternoon session was free of interruptions besides a brief Full Course Yellow period to retrieve the stricken UpGarage Honda, which resumed running after nearly an hour in the garage.
SUPER GT pre-season testing continues at Fuji Speedway on March 27-28.
Okayama testing times (GT500 class):
| Pos. | No. | Car/Team | Drivers | Morning | Afternoon |
|---|---|---|---|---|---|
| 1 | 36 | TOM'S Toyota |
| 1'18.116 | 1'20.652 |
| 2 | 23 | NISMO Nissan |
| 1'18.246 | 1'20.518 |
| 3 | 3 | NDDP Nissan |
| 1'18.487 | 1'20.560 |
| 4 | 37 | TOM'S Toyota |
| 1'18.581 | 1'21.126 |
| 5 | 100 | Kunimitsu Honda |
| 1'18.584 | 1'20.893 |
| 6 | 39 | SARD Toyota |
| 1'18.617 | 1'19.525 |
| 7 | 8 | ARTA Honda |
| 1'18.854 | 1'21.421 |
| 8 | 24 | Kondo Nissan |
| 1'18.887 | 1'19.668 |
| 9 | 19 | Bandoh Toyota |
| 1'18.906 | 1'19.733 |
| 10 | 14 | Rookie Toyota |
| 1'19.003 | 1'19.471 |
| 11 | 12 | Impul Nissan |
| 1'19.030 | 1'19.419 |
| 12 | 64 | Nakajima Honda |
| 1'19.219 | 1'20.412 |
| 13 | 16 | Mugen Honda |
| 1'19.273 | 1'20.824 |
| 14 | 17 | Real Honda |
| 1'19.621 | 1'19.361
|
| 15 | 38 | Cerumo Toyota |
| 1'19.522 | 1'19.968 |
Giuliano Alesi
Sho Tsuboi
Ronnie Quintarelli
Bertrand Baguette
