Rival Formula 1 manufacturers are intensifying efforts to alter the 2026 power unit regulations on compression ratio testing, targeting implementation before the Australian Grand Prix. Mercedes maintains its engine complies with current rules, while competitors suspect a loophole allows higher performance when engines are hot. Discussions in recent meetings have yet to yield a decision, requiring broad consensus for any change.
The controversy centers on Formula 1's new 2026 power unit rules, which cap the compression ratio at 16:1, down from 18:1 in prior regulations to aid newcomers. Measurements currently occur during static tests at ambient temperature. Rivals suspect Mercedes exploits thermal expansion to meet the limit in tests but exceed it under operating conditions, potentially gaining up to three tenths of a second per lap.
Audi, Ferrari, and Honda sent a joint letter to the FIA seeking clarification. Following an initial technical experts' meeting on January 22, further discussions included a Power Unit Advisory Committee session on Thursday. No final decision emerged, though proposals include testing engines after warming up or using sensors during track runs to capture hot conditions more accurately.
Red Bull's position has shifted, with reports indicating support for a change, aligning four of five manufacturers. However, any immediate modification requires a supermajority: backing from four manufacturers, the FIA, and Formula One Management. The FIA has so far endorsed Mercedes' interpretation, as confirmed by team principal Toto Wolff, who referenced FIA president Mohammed Ben Sulayem's view.
Wolff dismissed rivals' concerns ahead of Mercedes' season launch: "I just don't understand that some teams concentrate more on the others and keep arguing a case that is very clear and transparent... Get your shit together." He emphasized the power unit's legality under existing checks, standard even outside F1.
Red Bull team principal Christian Horner defended boundary-pushing as inherent to the sport: "Formula 1 is about pushing the boundaries. It’s about how you interpret regulations... you’ve got to be pushing the envelope."
With power unit homologation set for March 1, time is short for preseason changes, potentially delaying impacts to 2027. The FIA stated the matter remains under internal discussion, with updates forthcoming. This saga risks protests at the Australian Grand Prix if unresolved, underscoring tensions in the new era's technical landscape.
