Mercedes rivals handed 'skin in the game' ultimatum over F1 engine protest

Alpine managing director Steve Nielsen has challenged Mercedes' rivals to protest its power unit, arguing they ought to "put some skin in the game" over the controversial compression ratio issue.

Team Enstone is now a customer of Mercedes High Performance Powertrains (HPP) for 2026, having relinquished its works status at the end of last year in pursuit of being more competitive in the new era of F1.

The power unit and chassis regulations have been overhauled over the winter, and Alpine joins McLaren and Williams in taking a supply of power units and gearboxes from Mercedes HPP, which operates out of its Brixworth campus.

The contentiousness between Mercedes HPP and the other power unit providers — Red Bull, Ferrari, Audi and Honda — arises from a change in the rewritten power unit rules, which stipulate that compression ratios must now be set at 16:1, not the 18:1 they were previously.

In short, Mercedes has developed a clever way, or 'trick', to increase the amount of fuel that can be squeezed into the cylinder of its engine when running. This increased compression ratio subsequently increases power and could be worth up to a few tenths of a second per lap.

HPP has used materials in its power unit that expand when hot, meaning that when the engine is running, it increases the compression ratio from 16:1 to 18:1.

However, the rules also state that the compression ratio is to be measured at ambient temperature, by which point the engine cylinders have returned to the original specifications and therefore pass scrutineering.

"It very clearly says [it will be measured at] ambient temperature," Nielsen said of the rulebook when speaking to media, including RacingNews365, during the first pre-season test at the Bahrain International Circuit.

Putting their money where their mouth is

Despite the noise surrounding the issue and the pressure being applied by the other power unit manufacturers to have the FIA change the rules, the British engineer is not worried by the situation.

"It's a big regulations change," he said. "Some people have gone down one route, other teams have gone down another."

"My personal view is I'm not concerned about it, because I think the regulations are crystal clear on when the compression ratio is measured.

"Some other people are trying to introduce different parameters to that, and that's for reasons best known to themselves.

"But we've got full confidence in Mercedes. They've built a PU in good faith with a very clear set of regulations, and we're happy with it. And we trust the governing body to do the right thing."

There is an F1 Commission meeting next week in Bahrain, between the two official pre-season tests, and with it looking like Red Bull, Ferrari, Audi and Honda will propose a rule change so that the compression ratios are tested when the power units are at operating temperature, Nielsen feels the FIA risks setting a dangerous precedent.

Instead, the Alpine boss wants to see the correct avenues being used, challenging the other teams to mount a protest.

"I guess they've got their right to protest, I suppose," he added. "When we go to Melbourne, and if they really feel that strongly, then put some skin in the game and do something about it.

"I don't know whether the FIA will express a view on this before Melbourne. I kind of hope they do because I kind of hope the story of Melbourne isn't about compression ratios..."

Dangerous precedent

Nonetheless, a unified front by rival manufacturers at the F1 Commission meeting could result in a super majority vote in favour of a regulation change. However, any such amendment would need backing by the FIA and FOM, as well.

"The more fundamental thing for me is the way we're going about it," Nielsen said, raising a broader point about the long-term risks associated with a late alteration to the rulebook in such a manner.

"If we're saying that a very clearly-written set of regulations can be challenged in this way, then what else is off limits? Everything's up for discussion then.

"If a certain set of teams don't like something that's very clearly written, if suddenly you can have a lobby group and change it, then you're in a whole different world.

"People invest an awful lot of time and money — and particularly money — into this, in good faith.

"And if suddenly everything can be challenged — even though it's clearly written — for any reasons other than safety reasons, then I think that's a whole new world which we've not been in before...

"You could say I'm biased because we've got a Mercedes engine in our car, but I think the more fundamental question is: Do we really want a sport where clearly-written stuff can just be challenged because people fancy doing it? That's for the FIA to answer."

For a more detailed explanation of the issue, watch the video below!