March 2nd 2026

FIA to revise compression ratio tests from June

The FIA has confirmed it will change the way it tests the compression ratios of new Formula 1 power units starting June 1, following claims Mercedes had found a way to exploit the previous inspections.

This year the compression ratio limit of the fuel/air mixture in a power unit cylinder has been reduced to 16:1 from the previous 18:1, and was only previously tested at ambient temperatures. With that test written into regulations, Mercedes was believed to have found a way of potentially exceeding the limit when the car was running at higher temperatures, leading to a push from rivals for a change in the policing approach.

The FIA opened up the possibility for such a change via e-vote, and says the power unit manufacturers all unanimously agreed to testing at both temperatures from the middle of this year, and only at a representative running temperature from next season onwards.

“A significant effort has been invested in finding a solution to the topic of the compression ratio,” said an FIA statement. “This parameter, which was one of the key fundamental targets of these regulations in order to attract newcomers to the sport, is limited in the regulations to 16:1, measured in cold conditions.

“The FIA has worked to find a compromise solution which determines that the compression ratio will be controlled in both hot and cold conditions from 1 June 2026, and subsequently only in the operating conditions (130deg C) from 2027 onwards.”

As power unit manufactures had to homologate their designs before the start of the season, they effectively will need to be able to comply from now, even if the test doesn’t come into effect for another three months.

The FIA added that “further evaluation and technical checks on energy management matters are ongoing”, as the governing body and teams analyze whether changes to the amount of energy that can be harvested during a lap should be implemented.

The governing body has already stated it wants to see a bigger sample set of track running – beyond Barcelona and Bahrain used so far – to understand the impact of the new regulations on racing.

For more information: www.racer.com

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