Formula 1 is facing a major technical dispute ahead of the 2026 season after several manufacturers challenged how the sport measures engine compression ratios under the new power unit rules.
The FIA has called an emergency technical meeting for January 22, 2026, after Audi, Ferrari, and Honda raised concerns about a design interpretation reportedly used by Mercedes and adopted by Red Bull-Ford.
At the center of the dispute is Article C5.4.3, which sets a maximum compression ratio of 16:1 for the new engines. The rule was introduced to level the playing field and help new entrants like Audi compete.
Rival teams argue the issue lies in how the rule is tested. Compression ratios are currently checked under static, room-temperature conditions. Engineers claim some engines are designed to expand once hot, shrinking the combustion chamber during racing conditions.
According to the allegations, thermal expansion of pistons and connecting rods at operating temperatures above 100°C could push the effective compression ratio as high as 18:1, despite passing FIA checks when cold.
Teams estimate this could deliver a 10–15 horsepower gain and improve lap times by up to 0.4 seconds per lap, a huge advantage under the tightly controlled 2026 regulations. Higher compression also improves efficiency, a key factor with 100% sustainable fuels.
Audi, Ferrari, and Honda argue that cars must comply with the rules “at all times,” including during races. Mercedes maintains it followed FIA guidance and that its engine fully meets the current testing requirements. Red Bull-Ford is believed to be quietly supporting Mercedes’ position.
With the first pre-season test in Barcelona just days away, the stakes are high. The 2026 engines are already homologated, meaning any forced redesign could severely damage competitiveness.
FIA insiders expect a technical directive rather than a ban, possibly allowing current engines for 2026 while enforcing high-temperature compliance from 2027, in an effort to protect both fairness and stability.
