The direction of travel regarding the highly disputed Mercedes engine is becoming clearer. The other four manufacturers are pushing for the FIA to implement a correction to address the German team’s compression ratio solution.
Ferrari, Honda, Audi and now Red Bull have spoken extensively with the FIA on this issue. With the Australian GP only a month away, a combination of short and long-term responses are available.
In terms of more permanent solutions, the measurement technique for compression ratios could be altered. However, there is no defined timeline on when the necessary vote to approve this rule change would take place.
Because of this, another more immediate fix is under the microscope.
Multiple proposals under consideration
It takes little investigation to see how important the power units are for these regulations. Even before the Mercedes engine took centre stage, most discussions heading into 2026 were centred around the manufacturers.
When Bahrain testing begins next week, the engine suppliers will again be under immense scrutiny.
However, the development battle goes beyond the confines of a race circuit. Over recent months, lengthy discussions have taken place specifically regarding the Mercedes power unit.
Most recently, the FIA is considering altering the methodology for measuring compression ratios.
Rather than the existing tests, which take place at room temperature, the new suggestion is for technical delegates to conduct their tests when the engine is turned on – and therefore at a higher temperature.
Mercedes are understood to increase their compression ratio above the 16:1 ratio via clever use of thermal expansion. Therefore, carrying out tests with the engine at operating temperature would prevent Mercedes from exceeding the 16:1 limit.
Although Mercedes are opposed to this, the other four manufacturers are in favour. Red Bull were the latest and final engine supplier to put themselves at odds with the German outfit’s power unit.
This means there is now a sufficient majority for a vote to successfully change the compression ratio measurement. Critically though, it could take some time – and overcoming certain obstacles – for this process to reach completion.
Until this more definitive correction is implemented, there is another compromise being evaluated.
As previously analysed on LWOS, the new sustainable fuels will be game-changers in 2026. Some engineers believe the synergy between the 2026 fuels and power units could be worth more in performance than the engine design itself.
The fact many teams didn’t use the 2026 sustainable fuels in last week’s Barcelona Shakedown (due to fears of reliability) is evidence of how important this area is.
Returning to the Mercedes engine, there is an option for the German constructor to lower the caloric output of their fuel mix to start the season. As revealed by it.motorsport, this could take away the horsepower advantage gained from the compression ratio solution.