Mercedes boss Toto Wolff says he is 'philosophically' opposed to FIA's proposed mid-season rule change for F1 engines
The FIA has submitted a proposal for F1's engine rules to be changed during the 2026 season after lobbying from Mercedes' rival power unit manufacturers; watch the last day of the final week of testing on Friday from 6.50am, live on Sky Sports F1 and Sky Sports Mix
Thursday 19 February 2026 14:02, UK
Mercedes boss Toto Wolff says he is "philosophically" opposed to the FIA's proposal of a mid-season rule change over a contentious engine element, but says his team are willing to be "good citizens" by accepting it despite it potentially harming their performance.
A dispute over the compression ratio limit of Formula 1's all-new power units for 2026 had seen Mercedes' rival engine manufacturers lobby the sport's governing body to prevent the Silver Arrows from taking a perceived advantage of a loophole in the rules.
The FIA announced on Wednesday it had submitted a proposal for the loophole to be officially closed during the sport's summer break in August, which is set to be voted on before the season-opening Australian Grand Prix on March 8.
- When to watch final Bahrain pre-season test live on Sky Sports
- F1 2026: Testing, calendar, line-ups, new regulations, how to watch on Sky Sports
- Not got Sky? Get Sky Sports or stream with no contract on NOW📺
For the rule change to be passed, all four of the other engine manufacturers - Ferrari, Red Bull, Honda and Audi - must vote for the alteration along with the FIA and Formula 1.
As he addressed the announcement on Thursday at the penultimate day of pre-season testing in Bahrain, Wolff reiterated his position that Mercedes' rivals were exaggerating the importance of the issue but softened the stance he had previously taken of aggressively pushing back against a possible rule change.
Wolff said: "We said it all along that this looks like a storm in a teacup, the whole thing, and numbers were coming up that were… if these numbers would have been true, I absolutely understand why somebody would fight it, but eventually, it's not worth the fight.
"It doesn't change anything for us, whether we stay like this or whether we change to the new regulations, and that's been a process.
"But we also want to be good citizens in the sport because it doesn't make a big difference we then changed opinion.
"Philosophically, you can disagree with it because I believe regulations are there to be made and you keep the FIA close to you and that's how it should be.
"But if you have four other PU [manufacturers] that are putting immense pressure on the FIA, at a certain stage, what choice do we have than not to play?
"We were pretty comfortable in even having a protest going on Friday in Melbourne, but is this what we want?"
The compression ratio limit has been lowered from 18.0 under the previous ruleset to 16.0, but measurements are currently only taken when the engine is not running at full temperature, with Mercedes' rivals suggesting they are exploiting this by going above the limit when the engine is hot.
Pressed on whether the rule change could harm the performance of the Mercedes power unit, Wolff replied: "I think the way it's being done now [under the proposed change], that it needs to be compliant to the regulations when it's cold and when it's hot, doesn't give anybody an advantage.
"I think the attempt was from the other guys to have it only measured hot so they could actually have it cold outside of the regulations. So, now it's a fair game for everyone."
Wolff fumes at suggestion of 'illegal fuel'
Wolff also expressed frustration at reports this week that Mercedes' fuel supplier, Petronas, are facing a race against time to have its fuel approved for the opening race in Melbourne.
A report earlier this week on motorsport.com claimed Petronas, who will also supply fuel for the three others teams using Mercedes power units - McLaren, Williams and Alpine, have yet to obtain certification and homologation for their product.
The new sustainable fuels that are being introduced for the 2026 are subject to rigorous checks, and the report claimed a rejection of the Petronas product would see Mercedes and their customer teams forced to use a "provisional" fuel.
Asked about the reports, Wolff said: "This is another of these stories. We were told compression ratio is something that we were illegal, which is total bull***t, utter bull***t.
"And now the next story comes up that our fuel is illegal. I don't know, where that comes from and it starts spinning again.
"Maybe tomorrow we're inventing something else… god knows what?
"Another nonsense. This [the fuel] is a complicated topic and a process and all of this, but there's just not... I can't even comment."
Sky Sports F1's Bahrain Testing schedule
Friday February 20
Watch every race of the 2026 F1 season live on Sky Sports, starting with the Australian Grand Prix from March 6-8. Stream Sky Sports with NOW - no contract, cancel anytime
- 6.50am-11.05am: Morning session Live
- 11.55am-4.10pm: Afternoon session Live
- 8pm: Testing Wrap
