Ferrari, Audi, and Honda invoke article C1.5: Mercedes and Red Bull under close watch. Ferrari, Audi, and Honda raise concerns over Mercedes and Red Bull power units.

The 2026 Formula 1 season has not yet begun, but already rumors are circulating about alleged technical regulation violations by some teams. The upcoming championship will bring a major regulatory overhaul: revised power units, active aerodynamics, and many other innovations that will be detailed throughout the winter break.

Compression ratio under scrutiny

Even before the cars have been officially revealed, paddock insiders say there is already a hot topic making waves at FIA discussions: the compression ratio within the combustion chamber of the new internal combustion engine (ICE) component of the power unit.

Mercedes raises eyebrows, possibly not alone

According to the 2025 regulations, the compression ratio could not exceed 18:1 (the ratio between the total volume of substances in the chamber before compression and the volume after compression). For 2026, this limit has been reduced to 16:1.

However, according to reports by Christian Menath on Motorsport-Magazine.com, Mercedes—and probably Red Bull—may have found a loophole (though the exact method is not yet clear) to use a compression ratio very close to the 2025 limit of 18:1, potentially gaining around 15 horsepower.

Manufacturers appeal to Article C1.5

As soon as Ferrari, Honda, and Audi became aware of this, they requested clarification from the FIA, invoking Article C1.5 introduced in the 2026 regulations, which states: “Formula 1 cars must fully comply with the present regulations at all times during the competition.”

While monitoring aerodynamic components can already be complex—as seen with the flexible front and rear wings between 2024 and 2025—controlling what happens inside a power unit is even more challenging. According to Motorsport-Magazine.com, the FIA has launched an investigation focusing on the thermal expansion of certain internal components.

At this stage, checks are ongoing, and nothing has been confirmed. Further updates will follow.

Ultimately, this early technical standoff highlights the immense pressure and high stakes surrounding the 2026 engine regulations, as manufacturers scramble to ensure a level playing field before the first wheels turn. It remains to be seen if the FIA’s investigation will lead to a stricter enforcement of the compression limits or if the alleged advantage will stand.