© Richard Pardon for Mercedes-Benz Grand Prix Ltd.
Toto Wolff says “lobbying from the other engine manufacturers has massively ramped up” regarding the legality of Mercedes’ power unit.
The biggest controversy that emerged at the beginning of 2026, has centred around the legality of Mercedes’ new power unit.
More specifically, rival F1 teams have accused Mercedes and Red Bull of having found a way of getting around ‘compression ratio limits’, as described in the new regulations.
This has to do with how much the air-fuel mix in an engine is compressed prior to ignition. In the new regulations, the limit has been dropped from 18:1 to 16:1, to improve sustainability, and this ratio is measured when the engine is off at ambient temperature.
Since a higher ratio equals more power, it is implied that Mercedes and Red Bull have found a way to increase the ratio by using materials that expand at higher temperatures (temperatures achieved while the car is racing on the track). As already explained, the FIA’s current measuring methods do not measure the ratio in these conditions.
Rival teams believe this ‘trick’ should be made illegal by amending the regulations. Surprisingly, even Red Bull has now joined those who are calling for the regulations to be changed.
If this was to happen ahead of the first race of the season, Mercedes’ power unit could not be used in Melbourne.
When asked about this ahead of the first pre-season test in Bahrain, Mercedes team boss Toto Wolff reiterated that the team has complied with existing regulations while designing their engine.
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“You know, in this sport, the sport is full of surprises, so there is never a situation where you can say you’re sure about anything,” the Austrian said.
“All along the process, obviously, when you design an engine, you’re keeping the FIA very close to the decisions you make, and that’s what we did.
“And we have had all the assurances that it was, what we did was according to the rule, and it’s not even like we’re talking about some massive performance gain, and that’s what it was.
“But, I think all of our competitors got a little bit aggrieved and lobbied the FIA for a long time.
“And so far we trust in the governance of the body, that is the power unit advisory committee. We’ll see what that gives.”
When asked if Mercedes would consider legal action, if their engine was deemed illegal, Wolff said:
“There is no such scenario as we would sue anyone. In Formula 1 it is more essential than ever that you know what the rules are, but engineering ingenuity is always respected, and that’s why we always got to respect the governance of the sport.
“And if the governance of the sport decides to change the rules, be it against our position or for our position, we just have to get along with it, go along with it.
“Of course, you develop an engine over a long time, and you have lead times, and if you were to be told you can’t operate the engine in the way you have developed it, that could be quite damaging for the performance.
“I think that the kind of lobbying from the other engine manufacturers has massively ramped up over the last few months.
“I mean, secret meetings, secret letters to the FIA, which obviously there’s no such thing as secret in the sport, and that has brought it to the situation.
“As I said, there is a governance process, and if that governance were to vote for an engine regulation change, you just have to take it on the chin.
“It is what it is, and obviously in that case it would be detrimental for all of the Mercedes-Benz power teams.”
Toto added that if the FIA was to change the regulations, a different solution would have to be found, one that allows Mercedes powered cars to race.
“Well, if it becomes a regulation, you need to adhere to the regulation, and if you can’t adhere to the regulation, then the FIA needs to come out with some kind of invention, how to adjust for that, and that’s unclear to us.
“I’m a little bit more confused in the recent weeks about how it came to the point now that it suddenly became a topic, because until last Friday, I was given the impression that things wouldn’t change,” he concluded.
