F1 2026 pre-season testing: F1 moves to close engine loophole Mercedes are accused of exploiting

Mercedes team principal Toto Wolff insists their engine is legal and that its design has been approved by the FIA.

The compression ratio is a measurement of the cylinder displacement between the two extremes of the piston stroke. Rivals believe increasing this beyond 16:1 could give a gain of as much of 0.3 seconds per lap.

Williams team principal James Vowles, whose team use Mercedes engines, dismissed the debate as “just noise that will probably go away, probably in the next 48 hours”.

Red Bull’s position on the compression ratio argument has not been clear until now, following their entry as a power-unit manufacturer this season.

Red Bull team principal Laurent Mekies said on Wednesday: “We don’t think it’s noise. We think we must have the clarity on what we can and cannot do.”

The new engine proposal came on the same day as the F1 Commission discussed a variety of issues that have arisen from the first running of the cars under the new rules introduced this year.

These included the increased difficulty of the start process and the way energy deployment and recovery are controlled by the rules.