Ferrari insider explains Mercedes’ 2026 engine trick and its legality. Mercedes' 2026 engine "trick" explained: A Ferrari engineer weighs in on its legality.

A Ferrari engineer reveals whether Mercedes’ 2026 engine trick is legal and if Maranello will adopt it

A Ferrari insider has provided insights into Mercedes’ 2026 engine solution, revealing whether it is legal and whether Maranello might adopt a similar approach.

As reported by Leo Turrini on his blog Profondo Rosso, a Ferrari engineer shared details about the method Mercedes has implemented for their 2026 power unit. The discussion clarifies whether the solution is legal and whether Ferrari might follow suit.

Much has been said about Ferrari, Honda, and Audi trying to pressure the FIA to ban the ‘trick’ developed by Mercedes and Red Bull regarding compression ratios. If legal, this innovation could give the two teams an estimated advantage of around three-tenths of a second and roughly 15 horsepower over rivals. According to the Maranello engineer, here is what was explained to Leo Turrini:

“They have found a clever solution. The Ferrari engine to be homologated…”

“The compression ratio of an internal combustion engine is, simply put, the ratio between the maximum and minimum volume of the combustion chamber. From what I’ve read, Mercedes (and possibly some colleagues now working on Red Bull’s powertrain) have discovered a way for the materials in the combustion chamber to expand at high temperatures, increasing the maximum volume by 18 times compared to the minimum. I believe they have found a way to effectively ‘stretch’ the combustion chamber.”

The Maranello engineer attempted to explain in simple terms the technical innovation Mercedes pursued. Nicknamed ‘Deep Throat’ by the Italian journalist, he also commented on whether Ferrari could adopt a similar solution for their upcoming engine. According to him, there is no regulation breach.

“In my opinion, Mercedes’ solution is legal. Compression ratios can only be measured cold; measuring them hot is impossible. They have devised a smart solution. The Ferrari 067/6 engine, which will be homologated for testing and the first half of the 2026 season, does not use a similar approach. Likewise, the Ferrari 067/7 engine, which will run after the summer break, also does not adopt this method. If it works, it will be a significant advantage for Mercedes throughout 2026. To match it, Ferrari could only succeed by relying on the ADUO.”

For context, the FIA introduced the ADUO (Additional Development and Upgrade Opportunities) for 2026. This program provides extra development time and upgrade opportunities to teams at a disadvantage, allowing them additional hours on test benches to close the gap with faster engine manufacturers. Every six Grands Prix, the FIA evaluates power unit performance. Teams lagging by more than 2% in power may receive ‘development tokens’ or other benefits, including extra funding, more development hours, and budget flexibility. If Mercedes’ solution proves successful, it could have a decisive impact on the championship even before the season fully begins.