Toto Wolff has never been shy about turning the paddock’s volume knob up, but even by his standards the 2026 power-unit row has become unusually political, unusually fast.
Speaking during pre-season running in Bahrain, the Mercedes team principal claimed rival engine manufacturers have been escalating their campaign against a suspected compression-ratio loophole not just through the usual back-channel conversations, but via “secret meetings” and “secret letters to the FIA”. Wolff’s point wasn’t simply that competitors are complaining — it was that the temperature of the lobbying has spiked as homologation nears, and that the motivations are as much reputational as regulatory.
“I think that the lobbying from the other engine manufacturers has massively ramped up over the last few months,” Wolff said. “Secret meetings, secret letters to the FIA – obviously, there’s no such thing as secret in this sport – and that has brought it to this situation.”
At the centre of it is a technical dispute that’s already drifting into a broader argument about how, exactly, F1 intends to police its new engine rules once the real competitive pressure hits. Widespread reports in the paddock have named Mercedes as the manufacturer believed to be exploiting a gap in how compression ratio is defined and verified under the 2026 regulations.
The allegation, in essence, is that Mercedes has found a way for its power unit to effectively run at a higher compression ratio when the car is on track and heat-soaked — as high as 18.0 — while still meeting the stated 16.0 maximum when measured at ambient temperature. Rival manufacturers, unsurprisingly, have taken a dim view of that interpretation, and the push now is for the FIA to change the measurement approach in time for the opening round in Australia.
The timing is what makes this more than just the usual winter noise. The 2026 engines are set to be homologated by the FIA on March 1, a week before the first race in Melbourne. That puts the governing body in a familiar squeeze: act quickly and risk accusations of moving the goalposts, or move slowly and risk locking in an advantage that others believe was never meant to exist.
Wolff, for his part, insists Mercedes hasn’t been operating in the shadows. He’s repeatedly maintained the team kept the FIA informed during development and that the dialogue was constructive. “Communication with the FIA was very positive all along,” he said recently.
But his sharpest barbs in Bahrain were reserved for the motives he believes are driving the campaign. Rumours have circulated for more than a year that Mercedes’ 2026 preparation was ahead of the curve; the compression-ratio story broke into the open in December, and since then it’s evolved into a tug-of-war over definitions, procedures, and — crucially — what becomes precedent.
In Wolff’s telling, some of the urgency from rivals is rooted in the fear of being made to look silly once the lights go out.
“I think everybody was a little bit too excited about the performance of the Mercedes engine powered teams,” he said. “I think that our colleagues from the other brands have been carried away a little bit [with the fear] that this could be embarrassing, which I don’t think it is at all.”
There’s a familiar rhythm here. Every big regulation change produces at least one flashpoint where “innovation” and “circumvention” end up being separated by little more than a sentence in the rulebook and an FIA technical directive. What’s different this time is the squeeze created by homologation: once those specs are signed off, reversing course gets messy — politically and practically.
That’s why the “secret letters” line matters. It’s Wolff framing the story as a coordinated pressure campaign, not a good-faith technical clarification. And it’s also a reminder that in modern F1, the most consequential lap of the winter can be written on letterhead rather than driven on track.
A resolution is expected within weeks, and the paddock mood is that the FIA will have to land on something that can be defended both legally and competitively. If it sides with the push to change measurement conditions, Mercedes will almost certainly argue it has been penalised for reading the rules correctly — and for doing its homework early. If the FIA holds firm, rivals will feel they’re being asked to race against a loophole that’s been blessed by inertia.
Either way, this isn’t going to end with everyone smiling and going racing. It’s 2026. The new era hasn’t even started properly, and already the first real championship battle is being fought in the margins of the regulations.
As Wolff put it: “But it’s OK. Let’s see how the test pans out and then God knows what next black swan event is going to come to us.”
