The first laps in the 2026 race cars have yet to be driven, but a controversy is already brewing. With only six weeks between the Abu Dhabi Grand Prix and the start of the preseason, all teams and engine manufacturers are working hard to get both the cars and engines ready in time. However, an initial conflict over engine regulations is reportedly already raging between the teams. Both Mercedes and Red Bull Powertrains have allegedly applied a ‘trick’ to the compression ratio.
According to Motorsport Magazine, engine manufacturers Ferrari, Honda, and Audi are not pleased with this ‘trick’ by Mercedes and Red Bull Powertrains. The issue revolves around the compression ratio of the power unit. In 2026, this ratio may be 16:1, as opposed to the 18:1 that was still applicable in 2025. The compression ratio of an engine is the ratio between the largest volume and the smallest volume in the cylinder. According to multiple sources in the paddock, Mercedes has found a way to get the compression ratio back to 18:1. The team would not be violating the technical regulations in doing so. Reportedly, this gives the Silver Arrows a three-tenths time advantage.
Mercedes’ approach reportedly involves the fact that the compression ratio is only measured when the engine is not at full temperature. It is suggested that complex components in the engines are deliberately designed to expand as the engine heats up. This pushes the piston closer to the top of the cylinder during its cycle than when it is cold. This helps to increase the compression ratio – thus delivering extra performance and improved fuel efficiency – when the engine is running on the track. While thermal expansion of engine parts is a natural phenomenon, the new regulations do not specify what is considered an acceptable level for this.
Protests
Ferrari, Audi, and Honda have reportedly urged the FIA to implement regulatory changes prior to the Australian GP in March 2026. The FIA itself has stated that it is dealing with the issue. “The subject is still being discussed in technical forums with the engine suppliers,” said the governing body. “The FIA continuously monitors these kinds of issues to ensure fairness and clarity. Adjustments to the rules or measurement methods may be considered for the future.”
