Christian Horner responds to Red Bull and Mercedes power unit loophole rumours

Christian Horner faced questions about the rumours that Red Bull and Mercedes have found an engine trick ahead of the 2026 Formula 1 season.

While Horner was replaced in the role of Red Bull Racing CEO and team principal in July 2025, he was quizzed on the rumours during an interview with TODAY. Heading into a new set of regulations, reports emerged that both the Milton Keynes outfit and Mercedes had found a loophole in the regulations to increase the compression ratios.

For 2026, the engine's compression ratio is limited to 16:1. Generally, a higher compression ratio offers increased thermal efficiency. Mercedes and Red Bull are thought to have made use of the fact that it will only be measured when the car is static at ambient temperature, allowing the compression ratio to rise to 18:1 when the engine is in motion and up to operating temperatures, although it is worth noting that this has not been confirmed.

"Formula 1 is about pushing the boundaries. It's about how you interpret regulations. Always has been, always will be," Horner said as he danced around the question.

"Teams that are the most conservative are the teams that are never at the front of the grid. You've got to be pushing the envelope. And of course, it's all about how you interpret regulations, and engineers, some of the brightest engineers on the planet, will be looking at those regulations and thinking, 'OK, how can I maximise performance?'"

Mercedes team chief Toto Wolff responded to complaints from other power unit manufacturers at the official launch of the W17. "I just don't understand that some teams concentrate more on the others and keep arguing a case that is very clear and transparent," he said.

"Communication with the FIA was very positive all along and it's not only on compression ratio, but on other things too. Specifically in that area, it's very clear what the regulations say. It's very clear what the standard procedures are on any motors, even outside of Formula 1. So just get your shit together."

He added: "The power unit is legal. The power unit corresponds to how the regulations are written. The power unit corresponds to how the checks are being done."