Newey admits bias as Mercedes engine row intensifies ahead of 2026 season

summary: Aston Martin’s Adrian Newey concedes a conflict of interest in the debate over Mercedes’s alleged compression‑ratio loophole. Rivals demand a rule change before the 2026 season, and a super‑majority vote could strip Mercedes and its customer teams of a performance edge.

content:

Mercedes’s new power unit may be exploiting a grey area in the 2026 engine rules, prompting a united front from rival manufacturers. Aston Martin’s technical chief Adrian Newey, who runs a Honda power unit, openly calls out his own bias as the dispute moves toward a vote in Melbourne.

Why it matters:

The 16:1 compression‑ratio cap is a key cost‑control measure for the 2026 formula. An effective 18:1 ratio would give Mercedes a measurable lap‑time advantage, potentially reshaping the championship fight.

The details:

• Article C5.4.3 limits the geometric compression ratio to 16.0, measured at ambient temperature.
• Mercedes’s design reaches about 18:1 when the engine is hot, using the temperature‑based loophole.
• Ferrari, Honda, Audi and Red Bull Powertrains want hot‑condition measurements, via on‑track sensors or garage thermometers.
• A super‑majority of the five PU makers, the FIA and FOM must agree to amend the rule; teams themselves do not vote.

What’s next:

The Power‑Unit Advisory Committee will vote at the 2026 homologation meeting in Melbourne. If the rule changes, Mercedes will need to redesign its power unit and lose the current advantage. If the vote fails, the status quo stays, keeping Mercedes and its customer teams ahead for the opening races.