Kobayashi, who now looks set to stay on in the Japanese series next year after hinting at an exit previously, posted a time of 1m36.296s in his Toyota-powered KCMG SF23 on Thursday afternoon to end the three-day test on top.
The Le Mans 24 Hours lap record holder had an inauspicious start to the day when he crashed at the final corner and brought out an early red flag, but was able to return to the track later and set a time that was seven tenths quicker than the lap with which TOM'S driver Sho Tsuboi had topped the opening day's running.
