The fresh 2026 power units for Formula 1 are set to be introduced at the Circuit de Catalunya in slightly more than a month, yet uncertainties concerning an ambiguous aspect of the upcoming rules have already surfaced.
According to the German publication Motorsport Magazin, certain engine constructors have approached the FIA seeking further explanation concerning the compression ratio, a specification altered within the 2026 rulebook. This particular figure has been decreased from 18.0:1, as stipulated by earlier rules, to 16.0:1 for the forthcoming season.
Reports suggest that Mercedes, and possibly Red Bull Powertrains, have discovered a method to bypass the technical guidelines, which mandate that the compression ratio must adhere to the defined measurement when assessed at standard room temperature.
Concerns that the compression ratio could be altered with fluctuating temperatures have prompted Ferrari, Audi, and Honda to seek intervention from the FIA.
Scrutiny has centered on materials that might expand under increased operational heat, potentially boosting the compression ratio. Such a practice would contravene the technical rules, which explicitly state that vehicles must remain compliant throughout an entire race event.
Mercedes W16, technical detail
Photo by: Erik Junius
The FIA commented: “This subject has been and remains a point of discussion within technical groups involving the PUMs (power unit manufacturers), given that the updated limit inherently provokes inquiries regarding its interpretation and adherence. The FIA consistently examines these issues to guarantee equity and precision, and should it become necessary, might contemplate modifications to the rules or testing protocols moving forward.”
It is intriguing that concerns regarding Mercedes and Red Bull have emerged even before their engines have covered any distance on the circuit. This mirrors past instances in F1, where a mere personnel transfer can be sufficient to disclose a team’s or engine builder’s operations to competing entities.
The responsibility now rests with the FIA. The governing body affirmed: “The rulebook explicitly details the highest permissible compression ratio and the corresponding measurement technique, grounded in static conditions at room temperature.”
“This method has stayed consistent, irrespective of the decreased allowable ratio for the 2026 season. While it is accurate that thermal expansion can affect physical dimensions, the present regulations do not permit measurements to be conducted at higher temperatures.”
