Ahead of the start of the 2026 AUTOBACS SUPER GT series (opening round Okayama: April 11–12), changes have been made to the number of engines allowed for GT500 class and to the Success Weight system in the SUPER GT Sporting Regulations. This article highlights the main points of those changes.
*Text in red in the regulation excerpts indicates items newly introduced or modified for the 2026 season. The English translation is provisional. *The photos used with this article are for illustrative purposes only and are not directly related to the content.
2026 SUPER GT Sporting Regulations Art. 22 Vehicles and Engines 1. Reserve and/or spare cars are not accepted. 2. Changing cylinder blocks (crankshaft case and cylinders) or the chassis during the race will result in disqualification. 3. Chassis regulations for the GT500 – duty of continuous use throughout the season 1) All the new chassis introduced in the SUPER GT Series in 2025 must be used until the end of the 2027 SUPER GT season. Exceptional cases accepted by GTA shall conform to a separate rule.
＜omitted＞
4. Engine limitations usage for the GT500 vehicles 1) All vehicles that participate in the GT500 Class must use no more than 1 (one) engine for the entire season. The number of engines will be counted by the number of times it is sealed.
When a car has exceeded the officially allowed number of 1 (one) engine, this car will be penalized with a Penalty Stop after the start of the race for each occasion of engine replacement. The length of time of the Penalty Stop will be 5 seconds.
・In the GT500 Class, in order to promote engine development that balances cost reduction and durability, the three participating manufacturers have gradually reduced the number of engines permitted in a year (1 season) by mutual agreement. Up to last season, each car was allowed to use up to two engines over one season. Typically, teams would introduce a fresh engine in the latter half of the season to gain performance for the decisive stages of the title fight. ・From this season, as a further challenge to improve durability, the allocation has been reduced to one engine per car for the entire season. As a result, all hardware development effectively needs to be completed before the opening round, and engines are now required to achieve an even higher level of durability.
2026 SUPER GT Sporting Regulations Art. 23 Success Ballast (Additional Weight) System According to each race’s result, each racing car’s performance will be balanced (demoted accordingly) for the following race. 1． The drivers’ series points accumulated by the drivers registered with one respective car (car registration number) until the present event will determine the quantity of loading of the success ballast. The following applies to both the GT500 and the GT300 Class. 1）Until the 6th Round (time) of participation in the event in the same season:＜Success ballast = Drivers’ Series points × 2 kg (same as in 2025)＞ 2）Participation in the event for the 7th Round (time) in the same season:＜Success ballast = Drivers’ Series points × 1 kg (same as in 2025)＞ 3）Participation in the event for the 8th Round (time) in the same season:＜No success ballast will be loaded (same as in 2025)＞
2. The upper limit of the success ballast as mentioned above 1) is of max. 100 kg. Any excessive success ballast after this shall be exempt from loading, but shall still be accumulated to the total when exceeding this limit. 1）For GT500 cars, the imposed Success Weight is applied through a combination of adjustments to the diameters of fuel‑flow restrictor and refueling‑flow restrictor (hereinafter referred to as the ‘Success Refueling Restrictor’), in accordance with the amount of Nominal ballast weight. The specific adjustment settings for these Success Weight measures will be announced in the SUPER GT Race Bulletins.
*Detail of Setting will be announced in the SUPER GT Race Bulletins
2）For GT300 cars, when the imposed Success Weight exceeds 50 kg, additional Success Weight is applied through adjustments to the Success Refueling Restrictor diameter. The Success Refueling Restrictor is installed in the refueling system in addition to the flow restrictor specified by the BoP. The diameter of the Success Refueling Restrictor corresponding to the imposed Success Weight is defined according to the fuel flow restrictor diameter specified by each car’s BoP, and will be announced in the SUPER GT Race Bulletins.
3. The Success Refueling Restrictor must be installed directly below the automatic shutoff valve of the refueling system in accordance with Article 28, and must be sealed by the GTA. The Success Refueling Restrictor is supplied by the GTA as an integrated unit together with the coupler, and any modification or alteration is strictly prohibited. The Success Refueling Restrictor is not included in the minimum hose length specified in Article 28.
・To implement the move to a single-engine rule in the GT500 class, it became necessary to further restrict the fuel‑flow rate in order to secure sufficient engine‑durability margins. However, reducing the fuel‑flow rate below a certain threshold narrowed the speed gap between GT500 and GT300 cars, raising concerns over safety in multi‑class racing. ・Given these circumstances, when the Success Weight (SW) exceeds 68 kg—equivalent to a fuel‑flow restrictor setting of 88.0 kg/h or lower—the series has adopted a new approach for GT500, whereby refueling time in the race is adjusted using a Success Refueling Restrictor, in addition to the conventional onboard ballast and fuel‑flow restrictor. ・The introduction of the Success Refueling Restrictor to the GT500 class aims to ensure safety while further enhancing competitive balance under the Success Weight system. ・In the GT300 class, the Success Refueling Restrictor was already introduced last season, and it has now been formally defined in the regulations. ・When the imposed SW exceeds a certain level, the Success Refueling Restrictor limits the fuel‑flow rate during refueling in the race, increasing refueling time and consequently extending the duration of the pit stop. *For details on how the Success Refueling Restrictor works, please refer to “What is the new GT300 Success Weight rule, Success refueling restrictor?”, an article published when the system was introduced to the GT300 class last season.
