FIA Rules on Mercedes Engine Controversy
Formula 1's governing body has issued a final ruling on the Mercedes engine controversy, revising regulations to close a loophole related to engine compression ratios. The FIA reached a compromise with all F1 manufacturers to ensure parity and competitive fairness ahead of the 2026 season. F1 has also scrapped the mandatory two-stop rule for the Monaco Grand Prix after last year's controversy.
The controversy centered on the new 2026 engine regulations, which lowered the maximum compression ratio from 18.0:1 to 16.0:1. However, the rules initially only required this to be measured when the engine was at ambient temperature. Rival manufacturers, including Ferrari, Honda, and Audi, suspected that Mercedes (and potentially Red Bull-Ford) had designed components that expanded with heat. This would allow their engines to comply with the 16.0:1 ratio during cold inspections but operate at a higher, more powerful ratio of up to 18:1 when at full race temperature. This loophole was estimated to be worth an extra 15-20bhp, translating to a significant advantage of up to three-tenths of a second per lap. To close this loophole, the FIA will implement new checks starting June 1, 2026. From that date until the end of the season, compression ratios will be measured both at ambient temperatures and when the engine is hot (130°C). Starting in 2027, measurements will only be taken at the hot operating temperature. This compromise was unanimously approved by all five power unit manufacturers. The now-abandoned mandatory two-stop rule for the Monaco Grand Prix was an experiment for the 2025 race aimed at increasing strategic variety and excitement. The rule required every driver to use three sets of tires, forcing at least two pit stops. The rule backfired, leading to farcical scenes where teams used one car to deliberately slow down and back up the field. This created an artificial pit-stop window for their leading car, neutralizing the intended strategic challenge and leading to widespread criticism from fans and teams for creating a distorted and contrived spectacle.
