Insports car racing,balance of performance (BoP) is a regulation and mechanism that maintainsparity between competing vehicles by adjusting the limits and parameters of a vehicle such as horsepower, weight, engine management, and aerodynamics to prevent a single manufacturer from becoming dominant in a racing class or series.
The origin of the term "balance of performance" dates back to the creation ofGroup GT3 in 2005 for the 2006 racing season, using experience learned from thehomologation special phenomenon in previous GT classes.[1] The JapaneseSuper GT Racing series use of a different regulation calledsuccess ballast, which only affects the weight of a competing car. The aim of this system is to allow the development of various racing models within a class, without leading to an expensive development arms race between manufacturers.[1] The system was later adopted for other production-based racing categories such asGroup GT4,LM GTE andTCR Touring Cars. Since 2025, theBritish Touring Car Championship usesTTB (TOCA Turbo Boost) regulation, which only affects the turbo boost (power output) of a competing cars to achieve a similar outcome.[2] Althoughone-make,open-wheel andprototype car racing typically do not use a balance of performance regulation, a similar system was devised for theLMP1 class in theFIA World Endurance Championship calledequivalence of technology (abbreviatedEoT), that allows for parity betweenhybrid and non-hybrid cars in the class.[3]DPi cars in theIMSAWeatherTech SportsCar Championship are also subject to balance of performance regulations.[4]
Balance of performance is assigned by testing and analysis of a certain model's performance through previous races, and in some cases between sessions in the same race weekend. Alternate methods may be used if the competing vehicle is new. For example, for GT3 cars,SRO holds two balance of performance tests every year atCircuit Paul Ricard, with cars driven by racing drivers who already compete in them, in order to assess the performance of each car, and balance the performance of the vehicles accordingly.[1] These cars are equipped with an organizer-suppliedtelemetry device so that the organizer can gather data to allow the balancing of the cars, with new-to-class cars also subject towind tunnel anddynometer testing. Once the results are obtained, various aspects of the car that can affect the car's performance such as engine power, vehicle weight, and aerodynamics are adjusted.[4][5] By analyzing performance patterns of each car, organizers can change the balance of performance of a car at any point during the season.[6] Different series or organizers may calculate BoP differently depending on the conditions, with IMSA andACO applying different BoP calculations for LM GTE cars in their respective series.[7][6] The BoP for GT3 cars participating in Super GT's GT300 class are optimized to allow competition against cars built exclusively for the series.[8] TCR has a unique feature called compensation weight, as a further mechanism to balance the cars.[9]
Some manufacturers have been accused ofsandbagging, where a car would purposely underperform during a test, or during certain races, to receive favorable results later; for example, rival teams accused theFord GT (run byChip Ganassi Racing) of sandbagging during the2016 FIA World Endurance Championship season, even after performance adjustments for the qualifying session for the2016 24 Hours of Le Mans race.[10][6] Various rules have been made to deter this; IMSA mandated any car that is found to be sandbagging during the Roar Before the 24 (a testing session leading to the24 Hours of Daytona race) will serve a five-minute stop-and-go penalty during the race.[11]
Several racing games, such asGran Turismo Sport,[12]Gran Turismo 7,[13]RaceRoom[14] andAssetto Corsa Competizione,[15] also feature a simulated balance of performance for each playable car as part of the games'game balance mechanism.