What is the new GT300 Success Weight rule, Success refueling restrictor?

In SUPER GT’s unique Success Weight (SW) rule, the GT300 class had the Success refueling restrictor introduced from the 2025-season which will be applied to a car that has Success weight exceeding 50kg while, in return, the car will be waived of loading the ballast for the exceeding part of the weight. The new rule is intended to lengthen the duration of pit stop longer than usual so to add handicap to the car in the upper positions in the point standing but at the same time avoid having the maneuverability of the car to degrade to a level that would impact the safety to keep the excitement created by SUPER GT’s iconic intense battles on the track, which will also make it difficult for a same car to continuously finish the race in an upper position, the main objective of SW.

With an emergence of a car that has the accumulated weight of SW exceeding 50kg at the Round 3 Sepang in the GT300 class (No.65 LEON PYRAMID AMG / Accumulated weight: 72kg), this article describes how the Success refueling restrictor works once again.

The refueling device used in SUPER GT has a structure like in the below diagram. Refueling restrictor defined for each car model in the Requirements indicated in the bulletin issued for every event is attached directly under the refueling tank (green part). Newly introduced Success refueling restrictor will be attached below it (red part). It is instructed to attach to the connector extending downward from the tank of the refueling device, the large rectangle in the upper part of the diagram.

Below pictures show the actual connector (refueling restrictor embedded). “Orifice” indicated in the diagram is Success refueling restrictor. GTA provides Success refueling restrictor to the respective entrant (team) which then will be sealed.

Composing parts of Success refueling restrictor.

Orifice embedded in the parts.

Assembled Success refueling restrictor.

Installation to refueling device.

Sealed Success refueling restrictor.

The actual Success refueling restrictor used in Round 3 is in the photo below (equivalent to 68 – 84kg of No.65 car for Round 3).

Diameter of Success refueling restrictor is defined for each car model and has 3 levels which is reduced accordingly to the success weight of a car. Numerical values of the diameter were extensively researched and verified over a long period of time by considering various combinations of refueling device and car, conditions of event venue, and all car models and issued through a bulletin before Round 2. Below are abstracts of the car model and respective numerical value from the bulletin. It would be a good reference for the next race and beyond.

■Abstract from the bulletin: GT300 class refueling restrictor under Success weight rule.

◎Race car
・Mercedes AMG GT3
・Ferrari 296 GT3
・Nissan GT-R NISMO GT3
・SUBARU BRZ