A tense week for Mercedes. This week the Power Unit Advisory Committee (PUAC) will decide whether to change the regulations to end the controversy over the Silver Arrows’ alleged “engine trick.” The five engine manufacturers will vote on introducing a second measurement for the compression ratio. If approved, the change would only take effect midway through the 2026 season.
The FIA now confirms that an e-vote — a digital ballot — has been sent to all five engine manufacturers to vote on a regulation change. A second measurement — taken when the car is at the same higher temperature it reaches on track — would be introduced from August. The static measurements would remain in force. Manufacturers have ten days to cast their vote.
“Over recent weeks and months the FIA and the power unit manufacturers have jointly developed a method to quantify how the compression ratio changes from ambient to operating conditions,” the FIA said in a statement. “Following validation of this approach, a proposal has been submitted that from 1 August 2026 it must be demonstrated that the compression ratio limit is met not only at ambient conditions but also at a representative operating temperature of 130 °C (when the car is on track, editor).”
The extra measurement will only be introduced if a majority of the five engine manufacturers agree. Earlier sources reported that Ferrari, Audi, Honda and Red Bull are keen to push the change through.
