Why Ferrari doesn't believe new FIA engine tests will close Mercedes’ loophole

From 1 June, new FIA engine tests will close the compression ratio loophole that Mercedes has been exploiting under Formula 1’s 2026 power unit regulations. Yet despite the rule tightening, Ferrari is not convinced it will fundamentally shift the competitive order.

The compression ratio debate

Mercedes team principal Toto Wolff downplayed the advantage, suggesting it was worth only “2-3hp”. Red Bull’s Max Verstappen strongly disagreed, responding that “you definitely have to add a zero to that, and maybe even more.”

“I'm not convinced that the new compression ratio rule will be a huge game changer,” said Ferrari team boss Fred Vasseur. “It's more that you will have the ADUO at one stage – the introduction of the ADUO will be an opportunity for us to close the gap.”

ADUO: Ferrari’s strategic opportunity

The Additional Development and Upgrade Opportunities (ADUO) mechanism allows performance-based development adjustments during the season. Power units will be evaluated after the sixth, 12th and 18th grands prix.

At each checkpoint, manufacturers between 2% and 4% down on the best engine will receive one additional upgrade opportunity. Those more than 4% behind will be granted two.

Originally scheduled for evaluation after Miami in May, Spa-Francorchamps in July and Singapore in October, the cancellation of April’s Middle Eastern rounds has shifted the timeline. The reviews are now expected to take place after Monaco in June, Zandvoort in August and Mexico City on 1 November.

For Ferrari, this mechanism — rather than the compression ratio clarification — represents the more meaningful chance to close the gap.

More than just engine power

Vasseur was clear that Ferrari’s deficit cannot be reduced to a single technical parameter.

“But once again, it's not just about pure ICE performance,” he insisted. “I think you have a lot in the energy management, a lot in the chassis, and it would be a mistake from our side to be just focused on one parameter.”

The numbers underline the challenge. In qualifying so far, the leading Mercedes has been six tenths of a second faster on average. Ferrari has been closer in race trim, though Vasseur attributes part of that to Overtake Mode.

“At the beginning [of the Shanghai race] we were fighting with the Merc,” he explained. “As long as we are in the one-second [window], we can have the extra boost, and we are able to keep the pace, but as soon as they are making the one-second gap, it's much more difficult.”

He added that Ferrari tends to push harder in the opening laps of a stint before the underlying pace difference re-emerges.

“We are pushing perhaps a bit more than them on the opening laps, and then after the first 10 laps of each stint, we are coming back to the four, five tenths a lap that they have.”

A clear performance deficit

Ferrari’s weakness is most visible in straight-line performance.

“We know that we have a deficit of performance, mainly in the straight line, that we have to work on it,” said Vasseur. He pointed to incremental gains across recent sessions: “We were eight tenths off in Melbourne, six tenths on Friday, four tenths on Saturday. Step by step we are understanding a bit more the situation and closing the gap, but they are still far away.”

The team’s response is comprehensive rather than narrow.

“It's not just about the engine. It means that we have to work everywhere, we have to improve on the chassis, on the tyres, like always. Racing didn't change, all the components of the performance are still on the table and we don't have to be focused only on one parameter, but it's a challenge.”

Ferrari acknowledges the need to improve the internal combustion engine, but that will come after the ADUO evaluation.

“We know that we have to improve on the ICE – but this will be after the ADUO [evaluation] – on energy, on chassis, on aero. We are pushing like hell, on every single area to close the gap.”

The championship picture

The early-season standings reflect the scale of the task. Ferrari trails Mercedes by 31 points in the constructors’ championship, although it holds a 49-point advantage over third-placed McLaren. Ferrari customer Haas sits a further point behind.

The compression ratio loophole may soon be closed, but the numbers suggest Ferrari’s fight is broader and more structural. For Maranello, the real battleground lies in development execution — and in maximising the opportunities the ADUO system provides.