THE COMPRESSION RATIO CONTROVERSY THAT COULD SHAPE THE SEASON

Anything but a holiday break. In Formula 1, the action never really stops, and even over Christmas the sport continues to deliver drama. This time, however, it’s not about on-track battles, but about technical scenarios that could shape the entire 2026 season. Just a week after the compression ratio controversy surrounding the next-generation power units erupted—placing Mercedes and Red Bull under the spotlight—a new chapter has opened in what is starting to look like a long-running saga. One that could keep fans and insiders alike on edge until at least the season opener, if not throughout the entire championship.

Taking a step back, the technical regulations state—under Article C5.4.3—that from 2026 onward the internal combustion engines must run a compression ratio of 16:1, down from the 18:1 used through the recently concluded season. And yet, according to what has emerged, some manufacturers appear to have identified a gray area in the rules. In simple terms, while the engines are fully compliant during scrutineering checks conducted cold, once in operation they are reportedly able to achieve a higher effective compression ratio thanks to the thermal expansion of the materials involved.

In light of this interpretation, Ferrari, Honda, and Audi formally approached the FIA seeking clarification. As things stand, however, the solution appears to be legal: the declared data match the regulatory requirements, and the measurement procedures will not be changed, continuing to be carried out at ambient temperature. Moreover, Mercedes is understood to have already discussed the matter with the FIA and received approval, with both the engine and its components deemed fully compliant with the regulations.

Estimates suggest this approach could be worth up to 10 kW, roughly 13 horsepower. In lap-time terms, simulations of the 2026 cars indicate a potential advantage of three to four tenths of a second per lap, depending on the circuit. The benefit would not be limited to outright performance, but would also extend to improved fuel efficiency—no small detail, considering that there has already been talk of lift-and-coast techniques returning next year, even on long straights.

That said, there is a significant gap between theory and reality. Only track running will reveal how effective this solution truly is. At present, Mercedes and Red Bull are the only ones with partial answers, derived from simulations and dyno testing. It remains to be seen how close the two manufacturers have actually come, in real-world conditions, to the old 18:1 compression ratio.

What about the other engine suppliers? First, it’s important to note that reaction times in engine development are far longer than in aerodynamics. While a wing or aerodynamic appendage can be designed, produced, and introduced in a matter of weeks, power unit development requires much more time, taking into account production lead times and, above all, reliability. That said, it’s worth noting that the compression ratio issue has reportedly been known within the paddock for quite some time.

Given this context, two main scenarios emerge. The first is that rival manufacturers are already working to replicate what Mercedes and Red Bull have done, taking advantage of the remaining window before final homologation, which will take place ahead of the Melbourne Grand Prix in early March. This path is feasible, but it comes at a cost: additional development would eat into the budget cap margin available for in-season upgrades.

The alternative scenario is to observe the opening phase of the season and wait until the Miami Grand Prix. In 2026, every six races the FIA will conduct a performance review of the internal combustion engines only. If a performance disparity is identified, the ADUO (Additional Development and Upgrade Opportunities) mechanism will be triggered, allowing manufacturers to recover lost ground.

In practical terms, a power deficit of 2% compared to the best engine in the field would grant the disadvantaged manufacturer one development token, increasing to two tokens if the gap exceeds 4%. Before that can happen, however, the FIA must clearly define the intervention procedures. Only then can the engine supplier begin work, inevitably stretching timelines even further.

As a result, there is a very real possibility that any technical disadvantage may only be fully addressed in 2027, forcing some teams to endure a season as midfield players. It would come as no surprise if teams were to seek further clarification from the FIA in the coming weeks. Indeed, this situation could drag on throughout the championship, with protests and disputes potentially arising at every Grand Prix. Even before it begins, the 2026 Formula 1 season is already shaping up to be a hot one—fought not only on the track, but also behind the scenes in the technical offices.

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