During the fallow day between qualifying and the races at Oulton Park, the series organisers have released a revised balance of performance for a number of on the British GT Championship grid. This is in response to the exceptional pace shown by some of the entries during free practice and qualifying.

In the GT3 the BMW M4 GT3, Lamborghini Huracan GT3 EVOII and Mercedes-AMG GT3 all have changes to make. Note that the changes are to the pre-weekend BOP issued by the series and not the homologated figures for each car.

In GT4 the McLaren Artura is the car most affected by changes, which was almost inevitable given the blistering pace shown by the newest GT4 car in the class. The BMW M4 GT4 (G82) is also subject to an adjustment as is the Ford Mustang.

BOP, or Balance of Performance, uses combinations of weight, ride height, air restrictors and ECU software changes to level the playing field where quick sports coupes like the BMW M4 are racing against downtuned hybrid supercars like the McLaren Artura. The idea is that if the cars were driven by the same driver at the same time in the same race, they should cross the line at the same time.

Tweaks to BOP are not unheard of but are rare during while the race weekend is underway.

BOP Changes – What’s Been Done?

The BMW M4 GT3 has been increased in weight by 10 kilos compared to Saturday. Lamborghini’s Huracan GT3 EVOII on the other hand has been given a 10 kilo diet. For the Mercedes-AMG GT3, both the EVOs of 2 Seas Motorsport, RAM Racing and Greystone and the non-EVO car of Team ABBA, an additional 15kg of ballast has been added.

In GT4 it’s more complex. The BMW M4 has been given a change here, but its to one of the software throttle maps and we don’t know how it will change the performance of the car. In the Academy Motorsport garage the changes are a bit more manual, 15kg of ballast has been added while the minimum ride height at the front of the car has been reduced by 5mm. This will increase the rake angle of the car and improve the effectiveness of the rear wing.

In the 6 McLaren Artura GT4 garages the work is even more demanding. Weight is up by 10kg while ride height is up by 5mm at the front and 10mm at the rear. The air restrictors on the naturally aspirated V6 engine have also been changed.

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Nicholas Smith

Nick Smith is a time served motorsport journalist and photographer specialising in the British GT Championship. The originator of the idea behind the British GT Fans Show, which became the British Sportscar Podcast, Nick works as the shows resident expert. Away from the track Nick earns his way as a driving instructor and instructor trainer.

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