F1’s 2026 Engine Rules Face First Test as Teams Exploit Thermal Loophole
Mercedes and Red Bull Ford are reportedly leveraging advanced materials to gain a performance edge, sparking a new technical battle before the regulations even take effect.
The 2026 Formula 1 regulations have sparked their first major technical dispute, years before the new cars hit the track. A long period of regulatory stability in the sport is over, as engineers once again push the boundaries of the rulebook to find a competitive edge.
Formula 1 has always been defined by the ingenuity of its engineers to challenge limits and find clever ways around regulations for extra performance. This has been seen for decades in aerodynamics, engines, and fuels, but also in more intricate areas like tire heating, mirror placement, and the use of advanced materials with special properties.
A formal protest at the first race of the season is not out of the question.
Mercedes and Red Bull Ford Under the Spotlight
Mercedes and Red Bull Ford are at the center of the controversy, according to a report from The Race. The two power unit manufacturers have reportedly found a way to bypass the new 16:1 cylinder compression ratio limit. This revives a long-dormant battle over advanced materials, an area where exotic substances like beryllium were banned decades ago.
The new regulations for 2026 reduce the compression ratio from the current 18:1 to 16:1. This change was intended to slightly decrease the power from the internal combustion engine to compensate for the increased electrical power.
These two manufacturers, however, are not settling for that limit. They have found a way to increase the compression ratio without violating the rules by adhering to the FIA’s measurement criteria, but not during the engine’s actual operation on track.
The Key is Temperature
The method relies on thermal expansion. FIA regulations mandate that the compression ratio be measured “in static conditions and at room temperature.” Mercedes and Red Bull Ford are allegedly using specialized materials that expand as the engine heats up to its operating temperature. This expansion causes the pistons to rise slightly higher in the cylinders, effectively increasing the compression ratio while the car is running.
This engineering solution yields a significant performance gain of approximately 15 horsepower. It also improves fuel efficiency, placing rivals like Ferrari, Honda, and Audi at a potential disadvantage heading into the new era.
The FIA has acknowledged the situation, stating that “it is true that thermal expansion can influence dimensions at operating temperature, but the current rules do not require the measurement in conditions of heat.”
Future changes to the rules are now under consideration. The FIA stated it is “continuously reviewing these matters to ensure fairness and clarity and, if necessary, adjustments to the regulations or measurement procedures for the future may be considered.”
A major complication, however, is that the 2026 power units have already been homologated. Any rule change requiring modifications to core engine block components would create significant challenges for manufacturers at this stage.
If the FIA does not intervene, Mercedes and Red Bull Ford could secure a major early advantage. Their competitors would have little time to react and develop a similar solution.
A formal protest at the season’s first race, scheduled for March 6-8 in Australia, is also a possibility. Such a move would force the FIA to issue a definitive ruling, though the current regulations appear to offer little basis for a verdict against the two teams.
