Feb.9 (GMM) Mercedes’ controversial 2026 engine ‘compression’ concept is facing mounting political resistance, with Red Bull now reported to have switched sides and joined Ferrari, Honda and Audi in urging the FIA to clamp down.
The dispute centres on claims Mercedes has found a way to satisfy the FIA’s static, cold compression checks while achieving a higher effective compression ratio once the power unit is running at operating temperatures – a potential gain rivals privately put at around 10-15 horsepower.
The issue has simmered since December, but escalated after the Power Unit Advisory Committee (PUAC) met again last week, where proposals were discussed for how the FIA might refine the measurement process. One option under consideration is a shift away from cold testing to checks performed with warmed-up components – a move that would effectively end the alleged loophole.
Italian reports suggest the FIA is now weighing alternative procedures, though there is disagreement over how imminent any change might be. Autosprint claims the federation is prepared to move toward hot static testing as early as the Australian GP, pending a vote. Other outlets are more cautious, suggesting multiple proposals remain on the table and that formal approval would still require the usual political process.
What is clear is that Red Bull’s stance may be decisive.
Both Italian media and Sky Deutschland report that Red Bull Powertrains is now leaning toward aligning with Ferrari, Honda and Audi – a shift that would create the ‘supermajority’ needed for any procedural change.
The twist is that Red Bull had previously been linked to the very same concept. But with its first in-house engine program under intense scrutiny, the suspicion in the paddock is that Milton Keynes may prefer to block a Mercedes advantage – especially if it cannot replicate it in time.
Mercedes, for its part, remains defiant. Team principal Toto Wolff has repeatedly insisted the system complies with both the rules and the FIA’s existing test methods.
“The powertrain is legal. It complies with the rules. It complies with the testing procedures,” Wolff said. “That’s how we see the situation today, and that’s what the FIA has stated.
“So let’s wait and see. But we feel confident.”
Wolff had already told rivals to “just do your job”, arguing the regulations and their interpretation were “perfectly clear”.
Power units are due to be officially homologated on March 1, amid talk of a possible protest before the season-opening race in Melbourne a week later.