The FIA is seeking a vote from Formula 1 manufacturers on clarifying the 2026 engine compression ratio rules amid concerns over Mercedes' design. Mercedes team principal Toto Wolff described the controversy as a 'storm in a teacup,' emphasizing that his team kept the governing body informed throughout development. The proposed change would introduce an additional measurement at operating temperature if approved.
The Formula 1 paddock has been discussing the compression ratio for the 2026 power units, which regulations limit to 16:1. Mercedes' engine complies with this limit during static tests at ambient temperature but achieves a higher ratio while running, as permitted by Article C5.4.3 of the rules. This approach, developed in consultation with the FIA, has drawn criticism from the other four power unit manufacturers.
FIA single-seater director Nikolas Tombazis explained that the issue stems from a need to clarify regulations to align with their original intent, established in 2022 discussions with manufacturers. 'There are a lot of nuances when discussing such a matter, because there's what the regulations intend to be, and to keep the compression ratio at 16:1 was one of the core objectives,' Tombazis told Autosport. He stressed that no manufacturer is accused of cheating or breaking rules, but interpretations may have stretched the wording.
To address this, the FIA has proposed a vote requiring a supermajority: agreement from four of the five power unit manufacturers, plus the FIA and Formula One Management. Votes must be submitted online within 10 days. If approved by the FIA World Motor Sport Council, the change would take effect from 1 August, adding a measurement at a representative operating temperature of 130°C alongside the existing ambient check.
Tombazis noted that mid-season implementation balances fairness, as changes before the Australian Grand Prix were not feasible, and delaying until 2027 would allow unintended interpretations to persist. Manufacturers can modify engines to comply without falling under the ADUO homologation system, though such changes count toward the power unit budget cap. He described the required adjustments as minor, involving small millimeters in cylinder dimensions, and not requiring a full redesign.
Mercedes' Toto Wolff, speaking during Bahrain pre-season testing, downplayed the debate. 'We said it all along that this looks like a storm in a teacup, the whole thing,' Wolff said to Motorsport.com. He estimated the performance gain at 2-3bhp, contrasting Red Bull's Max Verstappen's claim of a larger difference, and affirmed Mercedes' willingness to adapt as 'good citizens' despite pressure from rivals.
Tombazis viewed the uproar as exaggerated due to the sport's competitiveness, suggesting the topic does not warrant months of attention.