The topic of engine compression ratios continues to stir debate in Formula 1. For Audi, seasonal exemptions are unacceptable. The team will rely on the FIA’s decisions, but if any system circumvents the spirit of the rules, it must be banned immediately. The upcoming technical meeting on January 22 will also focus on developing more effective monitoring methods, including under operational conditions.
On the technical side, discussions in the past month have centered on a potential solution developed by Mercedes and Red Bull that could exceed the 16:1 compression ratio set by the regulations. This device would offer an advantage in multiple areas, starting with increased thermal engine power.
Essentially, this solution ensures that during inspections at ambient temperature with the engine disassembled, as required by the regulations, the compression ratio appears fully compliant, within the 16:1 limit that all manufacturers aim to meet or approach as closely as possible.
However, once the power unit reaches its operating range, engineers could introduce a mechanism capable of raising the compression ratio to nearly 18:1. In practice, the effective hot compression would exceed the cold measurement, and this discrepancy has triggered a “war” among manufacturers over the legitimacy of the solution.
On one side, some argue that if the cold measurement is within the 16:1 limit, the hot value should not be decisive, similar to how wing flex is measured, where only the static deformation matters.
On the other hand, others insist that the 16:1 limit should apply under all conditions, regardless of whether the measurement is taken cold or hot. The regulations explicitly state that “no cylinder of the engine shall have a compression ratio exceeding 16.0,” a rule listed before measurement procedures, suggesting it is an absolute constraint.
Audi relies on the FIA but demands the right decision
The topic remains “hot,” as Audi technical director James Key discussed on the sidelines of the team’s 2026 presentation. “There’s a significant impact here. As always in these cases, we have to trust the Federation to make the right decisions. These are new regulations. We need a level playing field.”
Mattia Binotto shares the view, noting that if confirmed, such a solution would provide a clear advantage. It would not only increase power but also improve combustion efficiency, allowing teams to carry less fuel on board. “I don’t know if it’s true or not. At the moment, there are only rumors that Mercedes might have designed an engine capable of maintaining an even higher compression ratio under hot conditions.
“But it’s not my job to prove it. It’s not my responsibility to know. Everything is in the hands of the FIA. Rules are important, and their enforcement is important. If it’s true, it would certainly be a significant performance advantage and would make a difference on track,” Binotto added.
It is natural that different interpretations of the regulation arise, and the topic will be at the center of the January 22 meeting. According to Key, the principle is clear: if other manufacturers consider the solution non-compliant, a mechanism should be triggered for its immediate ban, not delayed until the end of the season.
No compromises will be accepted
There was speculation that any team using this solution could receive a sort of “pass” for the entire season, postponing the requirement to revise the project to next year. Key argues this makes no technical or sporting sense, and Audi would never accept it.
“If someone comes up with a clever diffuser and you say it’s not right, it doesn’t make sense that no one else can use it, but you can for the rest of the year. That’s illogical. We would never accept that.”
“So, if any system circumvents the spirit of the regulations, it must be controlled. And we trust the FIA to do so, because no one wants to spend a season watching if there’s an obvious advantage they can’t counter with an approved power unit. From our perspective, we hope the FIA makes the right decisions,” Key added.
January 22 meeting to explore new measurement methods
According to Mattia Binotto, the technical meeting on January 22 will not only address the immediate issue but also serve as a starting point to define a new monitoring methodology that allows compression ratios to be measured under operational conditions, not only cold.
“I don’t expect clarity or a compromise. The January 22 meeting will mostly continue discussions with the FIA on how we can improve or develop a future method to measure compression ratios in operational conditions. Currently, measurement is done cold with the engine disassembled. That’s why it only happens at the end of the season.”
“So you might have to wait until the end of the season to know if you are compliant. We are all trying together to develop a methodology that allows us to measure the compression ratio in real time while the car is on track. My hope for that meeting isn’t to clarify the regulation itself, but rather to define a method for the future.”
As the 2026 regulatory reset approaches, the battle lines are being drawn in the laboratory rather than on the asphalt. Audi’s firm stance, backed by veteran leadership like Binotto and Key, highlights the high stakes of the new Power Unit era. For a newcomer like Audi, ensuring that giants like Mercedes and Red Bull aren’t exploiting technical “grey areas” is vital to their long-term success. The upcoming meeting on January 22 may well determine whether the first year of the new era is defined by fair competition or a season-long technical dispute.
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