FIA adjust F1 regulations after Mercedes engine controversy

The FIA has confirmed an update to its technical regulations that has seemingly brought a resolution to the compression ratio saga.

Mercedes has been subject to intense scrutiny from other power unit manufacturers after it emerged it had found a trick with its engine ahead of the sport's new era.

As the sport's governing body sought a compromise, it confirmed that compression ratios must now be measured at 130 degrees Celsius as well as the traditional ambient-temperature testing that had previously been the sole compliance standard.

These new checks were due to come into effect at the start of August, following an agreement at a recent F1 Commission meeting - but it appears those plans have been scrapped.

Now, the new engine inspection rules will come into effect on June 1.

This has been outlined in Article C5.4.3 of the technical regulations, which states: “No cylinder, as referred to by C5.1.3, of the engine may have a geometric compression ratio higher than 16.0, measured in the following conditions: 

• Until 31 May 2026: when the Engine is at ambient temperature
• From 1 June 2026 to 31 December 2026: when the Engine is at ambient temperature as well as when the Engine is at 130degC. Any component, assembly, mechanism, or integrated arrangement of components that is designed or functions to in ratio in operating conditions beyond 16.0 is prohibited.

From 2027, the measurements will only be taken when the engine is at the previously specified hot temperature.

It means that Mercedes will retain the speculated advantage across the opening seven rounds before the changes are made.

The German manufacturer has played down the significance of the engine trick, but rival teams has suggested it could offer Mercedes-powered teams a major advantage.