DECEMBER 23, 2025

F1 engine row deepens, FIA weighing one-year compromise

The 2026 power unit controversy has intensified amid claims that Mercedes is not alone in exploiting a potential loophole, but may still emerge as the biggest beneficiary.

According to Italy's Corriere dello Sport, Red Bull Powertrains has also been attempting to reproduce the same system that allegedly allows Mercedes engines to reach an effective compression ratio close to 18:1 under running conditions, despite the regulatory limit of 16:1.

Seven months ago, a Mercedes engineer hired by Red Bull Powertrains shared this secret. Red Bull has since tried to reproduce this system, the newspaper reports.

However, it adds that the task has proven far from straightforward. Mercedes is said to have been working on the concept for more than a year and has built up a significant lead, while Red Bull has so far failed to replicate the same effect in the real world.

Red Bull have not yet managed to get close to an 18:1 compression ratio while driving. Mercedes has achieved this, Corriere dello Sport claims.

If the interpretation is upheld, the advantage would extend beyond Mercedes works cars to all customer teams using the German manufacturer's power unit in 2026, including McLaren, Williams and new customer Alpine.

A central problem, according to the Italian daily, is enforcement. The regulations specify that compression ratio checks are carried out at room temperature, creating a grey area once engines reach operating temperatures.

The manufacturers who ask the FIA for clarification indicate that the cars must always comply with the rules. However, it is difficult to prove this, even after a protest, the report states.

Corriere dello Sport says the regulations themselves leave space for this trick.

It is specifically stated in the regulations that the check is carried out at room temperature. This indirectly leaves room for free interpretations, and this was not the case with the old regulations.

With eight Mercedes-powered cars potentially enjoying a power advantage, concern among rival manufacturers is growing.

The teams try to solve these kinds of problems through weekly meetings. The concern now is that the eight cars with Mercedes engines will have more power, the report adds.

The FIA is now described as facing a major dilemma. Outlawing the system could severely handicap Mercedes, which is believed to have designed its 2026 power unit around the concept. Allowing it, however, risks triggering protests and political fallout once the season begins.

According to Corriere dello Sport, a compromise is being discussed - permitting Mercedes to use the system in 2026 only, provided it formally commits to abandoning it for 2027. Such a solution would likely allow Mercedes-powered teams to benefit for one season, a prospect that has already drawn strong opposition from rivals.

(GMM)