Written by Aaron Carroll, Edited by Vyas Ponnuri
BoP (Balance of Performance), commonly known as the equaliser in endurance racing circles, is going to be a big talking point heading into the 2025 season, once again. But, what exactly does it constitute?
Balance of Performance, or BoP as it is more famously known, was first introduced back in 2006 by the FIA (Fédération Internationale de l'Automobile) for the GT3 class of sports cars, the primary aim to allow the development of cars, without the expenses of a development arms race, and create competitive racing on track.
Since then, BoP has been implemented in series across the world, including WEC, IMSA, and GTWC to name a few.
The system works by setting limits on each car's power output, weight or even aspects such as aerodynamics or fuel capacity.
Organisers usually host test sessions with each competing car present before the start of each season, following which they will then pore over the data and formulate the BoP before the opening round.
Let's take an example to explain the phenomenon of BoP. In the recent GTWCE (GT World Challenge Europe) test, the Ford Mustang GT3 was 10 kph faster than its competitors.
The SRO (Stéphane Ratel Organisation), the group in charge of the GTWCE championship, will see this and set a limit on the power produced by the Mustang’s engine.
Usually, there will only be a small change (for example less than 10 horsepower), but each change is carefully calculated to give the closest racing.
Most systems would follow the process — using figures such as weight, power, etc — but some work slightly differently.
WEC hypercars for example, use the parameters of minimum weight, maximum stint energy, max power below 250 kph (155 mph) and power gain after 250 kph.
The top class endurance prototypes have an intricate system of sensors on the car. These sensors are concentrated on the driveshafts of the cars, not only to monitor the maximum power output of each car, but also alter the power output depending on the speed of the car, i.e above or below 250 kph.
They also can regulate the maximum stint length for each car by allowing more or less energy usage per stint.
This energy level is used for timing purposes and can be seen on graphics during broadcasts of the races, giving another level of immersion to fans.
Of course this sort of system presents challenges and certainly has downsides. In particular, sometimes BoP may not work as intended, delivering one car a distinct advantage over another by getting a ‘good BoP’. This can happen through human error or some other mistake or complication.
One such example of this was back in 2023 during the GTWC Europe round at Hockenheim, when Audi locked out seven of the top eight positions in qualifying.
This was especially controversial, with one of said Audis in the thick of a championship battle with a Mercedes.
SRO quickly rectified this issue, with all of the Audis gaining weight before the start of the race later that day, creating a more even playing field.
Even so the damage had already been done, with four of the top seven finishers in race one being from the German marque.
This sort of slip up can lead to all sorts of complaints from drivers and teams in the media about how their car didn’t have a favourable BoP, creating more issues for the organisers of the event.
Usually though the system does work well to create a level playing field, and acts as a catalyst for the close wheel-to-wheel action it’s set out to create.
Overall, despite the flaws, BoP is the system to credit for a lot of the close action in modern sportscar racing and will be sticking around for a long time to come.
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