Formula 1: What changes has the FIA ​​made to engines since June 1st?

It all began on February 27th. At the request of the teams, the FIA, FOM, and the engine manufacturers of the Formula 1, voted on a series of amendments to the 2026 regulations, including one on the measurement of engine compression ratio, resulting in a slight modification of the regulations during the season.

Until May 31st, engine compression ratio checks were performed with the engine cold, at ambient temperature. This was insufficient in the eyes of several racing teams. Because it's once the engine is running that suspicions arise, particularly concerning the engine itself. Mercedes Benz.

What does the new regulation stipulate?

The 2026 regulations set a clear limit of 16:1 compression ratio. However, several teams believe that the Mercedes engine achieves a much higher ratio once it reaches full operating temperature, thanks to material deformation under the effect of heat. This would allow the Silver Arrows to reach a value close to 18:1, gaining up to 10 to 15 additional horsepower. Beyond simply circumventing the regulations, Mercedes would hold a considerable advantage of around three-tenths of a second per lap. No real proof has been provided. Toto wolffThe Mercedes F1 boss vigorously denied the figures put forward, but the discussions within the paddock were heated enough for the FIA ​​to react.

Therefore, from June 1st to December 31st, 2026, Article C5.4.3 of the regulation is amended: the compression ratio must be measured under two conditions, cold and at 130°C, corresponding to the engine oil temperature. A further clarification is added to this article: no internal device may allow this ratio to be increased beyond 16:1 during operation.

This change to the regulations will be effective from the Monaco Grand Prix on June 7th until December 31st, 2026, before the control is focused exclusively on hot operating conditions from 2027.

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