The FIA has confirmed important changes to the compression ratio regulations in Formula 1 engines, which are expected to significantly affect cars with Mercedes engines. The change was announced after months of intense discussions and lobbying from competing teams, being one of the main points of debate during pre-season testing in Bahrain.
Read more F1: FIA changes engine compression rule and hits Mercedes
This new regulation establishes that the engine temperature will be measured at 130°C, in addition to the original specification that required testing at ambient temperature. The change, which was previously scheduled to be implemented in August, will now take place in June 2026, marking a major shift in the F1 Commission’s initial plans.
Article C5.4.3 of the technical regulations now specifies: “No cylinder, as described by C5.1.3, of the engine may have a geometric compression ratio higher than 16,0, measured under the following conditions: until 31 May 2026, when the engine is at ambient temperature, and from 1º June to 31 December 2026, both at ambient temperature and at 130°C. Any components, assemblies or mechanisms designed to operate with a compression ratio higher than 16,0 are prohibited,” says the new text of the technical regulation.
This change puts Mercedes under pressure, as the team will need to modify its power units to meet the new regulation, affecting not only its own team but also its customer teams, McLaren, Alpine and Williams, with the deadline approaching rapidly in June.
