McLaren: Engine compression ratio saga "typical politics of F1"

McLaren CEO Zak Brown thinks the ongoing saga around Mercedes and the compression ratio of its power unit is "typical politics of Formula 1".

The compression ratio of the V6 combustion engines, which measures how much the air-fuel mixture inside a cylinder can be compressed, has been reduced to 16:1 for this generation of power units - partly to help make building engines more accessible to newcomers like Audi.

But Audi, Honda and Ferrari all believe Mercedes has found a clever way to comply with the 16:1 compression ratio in cold and static conditions, which is how it is measured by the FIA, while expanding it under hot, running conditions and gaining a significant advantage. Mercedes is adamant its power units are fully legal.

Brown, whose outfit is one of four Mercedes runners alongside the works team, Williams and Alpine, has dismissed complaints about the Mercedes power unit as political gamesmanship.

"It's typical politics of Formula 1. The engine has been designed and totally compliant within the rules," he said at the launch of McLaren's 2026 challenger the MCL40. "That's what the sport is about. No different than things like double diffusers that we've seen in the past where they're compliant within the rules.

"I don't believe there's a significant advantage as being represented by the competition, but of course their job is any perceived advantage, they'll make a story out of it. But the reality is the engine is completely compliant [and] passed all its tests. And I think [Mercedes] HPP has done a good job."

McLaren MCL40 livery

Photo by: McLaren

The matter has been discussed at length by the FIA and by F1's Power Unit Advisory Committee, with some of the ideas being floated to clamp down including tests after the engine has first been warmed up, or for the FIA to use additional sensors to measure the phenomenon while running.

Any changes to the FIA's testing procedures or any other power unit tweaks would have to clear the usual governance processes and gain a supermajority, which means backing by four out of five manufacturers, the FIA and commercial rightsholder FOM. Red Bull-Ford Powertrains, which was initially believed to benefit from the same interpretation of the regulations, would also have to vote for such change.

The FIA is keen to draw a line under the controversy, so it doesn't spill over into the 2026 season. But the short-term changes Mercedes' rivals are pushing for ahead off March's Melbourne season opener still seem unlikely, as they could force the manufacturer to make changes that may not be feasible before the season opener.

Despite this, Brown doesn't subscribe to fearmongering that Mercedes teams will end up being unable to run in Australia.

"I can't imagine that you wouldn't have Mercedes teams on the grid in Australia," he said. "We're not privy to those conversations, so I wouldn't even know from a power unit point of view what would be required to change the regulations. But we'll have all the Mercedes teams on the grid in Australia, I'm sure."