GTA announced requirements (Balance of Performance (BoP), etc.,) for each car to be applied for the OKAYAMA GT 300km RACE, Round 1 of the 2025 AUTOBACS SUPER GT series. These requirements will be announced in a bulletin before each round of the series and competitors will have to prepare their cars accordingly. Please note that the contents from the bulletin below are excerpts selected for ease of understanding and they should not be taken as the actual contents in the officially released bulletin. In case of a need for a precise interpretation, be sure to check the original bulletin.
（Blue underlines: Changes from the 2025 Official Test at Fuji）
■GT500 Class
A fuel flow restrictor with a capacity of 95.0kg/h must be fitted to each car in accordance with the Success Ballast System, Art.23 of the SpR, and a re-fueling device flow restrictor (internal diameter: 25.0 mm) is also applied. Refer to the end of the section for the mounting positions etc.
■GT300 Class
The BoP regulations for the GT300 class FIA-GT3 cars have been decide based on consultations between GTA and SRO (organizers of IGTC, GTWC, etc.).
○GT300
*1 The shape of the refueling restrictor must maintain the shape of the “flow restrictor” in accordance with the 2025 JAF National Competition Vehicle Technical Regulations Chapter 3, Art. 10 10.3.2, figure 3-2. *2 For HYBRID cars, data separately specified by the GTA must be submitted. *3 Minimum ground clearance: A spacer with the thickness mentioned above shall be fitted between the reference plane and the skid block having a thickness of 10 mm (± 2 mm).
○GT300 Mother Chassis
*1 The shape of the refueling restrictor must maintain the shape of the “flow restrictor” in accordance with the 2025 JAF National Competition Vehicle Technical Regulations Chapter 3, Art. 10 10.3.2, figure 3-2. *2 Minimum ground clearance: a 10 mm spacer shall be fitted between the reference plane and the skid block with a thickness of 10 mm (±2 mm). *3 The fuel capacity carried on-board is limited to 110 liters.
○FIA-GT3
*1 FIA-GT3 cars must be fitted with an air restrictor with a shape that complies with the dimensions specified by the FIA. *2 The shape of the refueling restrictor must maintain the shape of the “flow restrictor” in accordance with the 2025 JAF National Competition Vehicle Technical Regulations Chapter 3, Art. 10 10.3.2, figure 3-2. *3 Any additional ballast must be mounted in accordance with the 2025 International Sporting Code, Appendix J, Article 257A, Article 204. *4 The above table shows the required specifications when using the Krontec 88K SL. When using other Krontec rigs parts, the specification should be 27.4mm.
○Maximum boost pressure
The maximum boost pressure level is calculated by applying the above boost pressure ratio to the standard air pressure announced by GTA. At each race event, the teams must adjust the maximum boost pressure in accordance with the local air pressure announced by GTA.
