FIA launches e-vote on F1 2026 power unit compression ratio change

Thomas Maher 18 Feb 2026 1:51 PM

Mercedes' George Russell at Bahrain testing, 2026.

The FIA has launched an e-vote with the power unit manufacturers, aimed at introducing a new compression ratio methodology from August 1.

The governing body has confirmed the nature of the proposed changes to the power unit compression ratio measurement methodology that has been put to the power unit manufacturers.

FIA confirms e-vote on compression ratio rule changes

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Following several meetings of the power unit advisory committee [PUAC] recently, a vote has been submitted by the FIA to the power unit manufacturers to evaluate an amendment to the regulations.

However, this vote will be carried out via e-vote, rather than a specific meeting of the PUAC.

The vote is set to centre on the nature of the compression ratio methodology used to measure the geometric ratio of the cylinders.

The regulations state that this ratio cannot exceed 16:0, with the measurement being taken at ambient temperature.

Speculation has suggested that Mercedes‘ power unit, of the five power unit manufacturers [PUMs] could have exploited a grey area of wording in the regulations pertaining to this ratio measurement protocol, perhaps exceeding this compression ratio whilst still meeting the terms of the measurement.

The four non-Mercedes PUMs have sought to gain further clarity on this, and are understood to have presented a methodology to allow for measurement at hotter temperatures, ie. while on track.

This was not a stipulation under the regulations as originally written, with the FIA outlining that the testing protocol would take place at ambient temperatures.

With the four PUMs needing to form a supermajority to get such a methodology change introduced into the regulations, the FIA has now confirmed that an e-vote will be held on the topic, with an eye to introducing such a test from August 1.

“The FIA has recently launched an e-vote primarily centred on a proposed change to the assessment of the power unit compression ratio in running condition,” read a statement from the FIA issued to PlanetF1.com.

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“Over recent weeks and months, the FIA and the Power Unit Manufacturers have collaboratively developed a methodology to quantify how the compression ratio changes from ambient to operating conditions.

“Following validation of this approach, a proposal has been submitted whereby, from 1 August 2026, compliance with the compression ratio limit must be demonstrated not only at ambient conditions, but also at a representative operating temperature of 130°C.

“The vote has been submitted to the Power Unit Manufacturers, and its outcome is expected within the next 10 days and will be communicated in due course.

“As with all Formula 1 regulatory changes, any amendment remains subject to final approval by the FIA World Motor Sport Council [WMSC].”

Logic would dictate that the four PUMs will thus vote in favour of the change in regulation, with Mercedes likely to vote in the opposite direction.

To form a supermajority, it’s understood the four PUMs will thus need to secure the FIA and FOM’s agreement to vote in the same direction – six of the seven parties on the PUAC must agree in order to progress the rule change.

Should this supermajority be formed, the matter will then go before the World Motor Sport Council for formal ratification into the regulations.

On Wednesday, Williams’ James Vowles, whose team is powered by Mercedes engines, was likely referring to this e-Vote when asked by PlanetF1.com about the significance of the situation and the extent of the furore.

“There will be a resolution, I’m sure,” he said.

“For me, it’s just noise. Frankly, it will go away probably over the next 48 hours, is my guess, but I understand why everyone was focused on it.

“But that isn’t the big ticket item, I would say, in this championship race.”

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