19 April 2018SGT

SUPER GT Official Test Fuji Speedway
8-hour Official SGT test was completed mainly focusing on longer runs

Further to the test held at Okayama International Circuit the previous week, Fuji Speedway hosted an official SUPER GT test on Saturday 24 and Sunday 25 March, with 42 GT500 and GT300 cars participating to the test. SUBARU BRZ GT300 also attended the 8-hour test which attracted a big crowd, to improve their car settings.

The first day of the test, on the 24th, saw a cloudy weather with an air temperature of 15 degrees C and a track temperature of 25 degrees C, which is an average condition for this time of the year. Although Fuji Speedway is the home circuit for R&D SPORT in charge of the team operation, it will be the first time they will run this year’s BRZ GT300 after the Shakedown test on 22 February. On that day, snow interrupted the Shakedown session in the afternoon so another test run was scheduled for the following day, but lower temperature meant that it did not reflect the actual race season conditions. So this time the drivers were able to go flat out at Fuji.

As represented by its 1.5km straight, Fuji Speedway is one of the fastest tracks in Japan. The development theme for this year’s SUBARU BRZ GT300 car is lower drag (to reduce air resistance) - design work was done on the rear end of the front fender, the angle of the canard and the new shape of the read end of the rear fender to contribute to decrease the drag. The test will validate how those changes will affect the handling and the lap times. On the first session of the first day, the team will look for the ideal aerodynamic balance of the car for instance by adding an attachment to the rear of the front fender.

Toyohiko Mouri, Director of body engineering at STI in charge of bodywork and aerodynamic performance, said: “This year’s bodywork focuses on reducing the air drag in order to increase the speed. However, we have to find the balance with the downforce so that we can get the right level of tyre grip. We shouldn’t have a car that is fast at the straight but slow everywhere else. We have to take into account various factors such as suspension, tyres and track conditions so that we can find the optimal combination of all those aspects. Drivers will also give their opinion and suggestions. We are steadily working on improving the current condition to the next level, step-by-step. As a result, maybe we will get more downforce but it is important to be able to select a lower drag option. Due to the characteristics of the circuit, it is possible to regulate the flow of air through adjusting the wings and canard.” The test for the BRZ GT300 went smoothly until a problem happened towards the end of the afternoon session, which was interrupted with half an hour of running time remaining.

The second day was sunny and crisp as we saw a beautiful Mt. Fuji covered with snow from the circuit. The problem was solved the previous day so the SUBARU BRZ GT300 started its session as scheduled from 9:00am. There were rookie drivers from other teams participating in the session so this SUPER GT official test involved a 15-minute Safety Car practice with all the cars running, at the beginning of the morning test. When free practice started, the R&D SPORT team started its long stint runs. Driver Yamauchi started, followed by Iguchi, and fully used the 2 hours allotted time to keep on running. The lap times were steady and the previous day’s issue did not seem to influence the performance. Driver Hideki Yamauchi said: “Too bad we experienced an issue yesterday but today, it was good we managed to do long runs from the morning. I am getting used to the low drag aerodynamic setting so I would like to attack more on the crucial third sector (the section in the second half of the track with a succession of corners).” Driver Iguchi commented: “We did long stints with my teammate Yamauchi to try to test new tyres and the ones we used so far. The new tyres worked best so we have retained a lot of positives from the session. As the track temperature rose it was easier to drive, and the lap times became more stable. As the handling was a bit peaky, I had the dampers adjusted a bit to prepare for the afternoon session.”

R&D SPORT continued long runs during the afternoon session. Once all the cars participated to the start practice, Iguchi started the run on the BRZ GT300. Because of issues with GT500 cars, the session was stopped twice with a red flag and the long stints had to be interrupted each time. Still, Iguchi managed to run 30 laps in total then changed to Yamauchi. After the interruptions he only had half an hour left to drive but he managed to check his settings and concluded two days of meaningful test. Iguchi who drove about 60 laps (approximately 265 km) on the second day said with a smiling face: “I now have a better idea about the tyre choice and I was able to drive many laps so it was a positive test. In the afternoon, after having the damping force of the dampers adjusted, the instability of the car behaviour when passing on bumpy areas of the track improved but I felt some more adjustment was still necessary. However, I have driven a lot today so I feel tired but great.”

Makoto Shibuya, the STI project general manager commented: “On the first day, the issue with the power unit shortened the driving time but otherwise we were able to complete the test as planned. We feel we can see the direction where we should head to regarding the aerodynamics setting and handling balance. If we take the top speed at the straight, the car is clearly faster than last year. We have also tested a few types of tyres and collected the data. When we can drive a long distance, we can get many positives from it. We will continue improving the driveability while preparing the car for the first race of the season at Okayama International Circuit.”