Controversy erupts over 2026 F1 regulations as Red Bull and Mercedes have reportedly exploited an engine loophole leading to protests from rivals

Reports of Red Bull and Mercedes finding a loophole in the technical regulations for the 2026 season came out a few days ago. The same had led to a controversy, with the rival team protesting and the FIA having to step in and investigate the same.

F1 introduced major technical changes for the 2026 season, including chassis, aerodynamics, and the power units. This is arguably going to be the biggest change since the 2014 season, when the V8s were replaced by the V6 Turbo Hybrid power unit.

With teams comprehensively developing the new power units and an all-new technical rule book for every manufacturer, any little advantage could make the difference. Amid this, Red Bull and Mercedes have reportedly found a loophole where the compression ratio of the internal combustion engine (ICE) increases as the unit heats up.

The 2026 regulations state that the compression ratio needs to be 16:1 or under. The FIA test for the compression ratio is conducted at ambient temperatures, where the Red Bull and Mercedes ICE will pass the test. However, as per the reports, Red Bull and Mercedes might be using materials that expand as the ICE heats up, and will increase the compression ratio.

F1 Grand Prix of Las Vegas - Source: Getty

The reports have led to the rival manufacturers, including Ferrari, Audi, and Honda, to request FIA’s involvement regarding the same. FIA responded to the controversy around the ICE compression ratio regulations, as the statement read,

“The topic has been and continues to be discussed in the technical forums with the PUMs (power unit manufacturers), as the new limit naturally raises questions about interpretation and compliance. The FIA continuously reviews such matters to ensure fairness and clarity and, if necessary, may consider changes to the regulations or measurement procedures in the future.”

The 2025 iteration of the 1.6L V6 Turbo Hybrid engines allowed for a compression ratio of 18:1, which was reduced for the 2026 season.

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“This procedure has remained unchanged”: FIA on the potential of changing the compression test procedure following the Red Bull and Mercedes controversy

The 2026 F1 car launches will begin as early as January 15 with Red Bull and Racing Bull, and the first pre-season testing will take place from January 26 to 30. Making it just a little over five weeks until the F1 test. The same timeline makes it difficult for FIA to make any changes to the technical regulations, and for the teams to comply with and make those changes.

As far as changing the procedure of testing the compression ratio, FIA’s statement read,

“The regulations clearly define the maximum compression ratio as well as the method for measuring it, based on static conditions at ambient temperature. This procedure has remained unchanged despite the reduction in the permitted ratio for the 2026 season. It is true that thermal expansion can influence dimensions, but the current rules do not provide for measurements to be carried out at elevated temperatures.”

Some reports suggested that the increase in compression leads to a possible advantage of 15 horsepower to Red Bull and Mercedes, worth around three tenths of a second a lap.

Edited by Pranay Bhagi