The Federação Internacional of
The suspicions involve the geometric compression ratio in the cylinders of internal combustion engines. The 2026 regulation limits this value to 16:1, a reduction from the 18:1 allowed until 2025.
The controversy arose before the start of pre-season testing, scheduled for Circuito of Barcelona-Catalunya.
Details of the alleged technical breach
The compression ratio defines the efficiency in compressing the air-fuel mixture.
Higher values increase power, but increase temperatures and mechanical loads.
The FIA lowered the limit to balance performance with the triple increase in electrical power in the new power units.
- Current measurements take place in static conditions, at room temperature and with the engine switched off.
- Projects from Mercedes and Red Bull supposedly respect the limit under these conditions.
- During operation, thermal expansion of components could increase the effective ratio to close to 18:1.
This difference could generate an estimated gain of 15 horsepower, equivalent to 0.3 seconds per lap on circuits like Melbourne.
Official FIA position
The entity confirmed that the measurement method remains unchanged from previous regulations.
A spokesperson stated that the rules clearly define the upper limit and procedure based on static conditions at room temperature.
Thermal expansion influences dimensions in operation, but measurements at high temperatures are not currently required.
Discussions on technical forums
The topic is continually debated with power unit manufacturers.
New boundaries raise natural questions of interpretation and compliance.
The FIA monitors the situation to ensure fairness and clarity.
Adjustments to measurement regulations or procedures may occur in the future if necessary.
Recent changes to the regulation
Updates published in December require FIA Departamento Técnico approval for measurement methods.
Each manufacturer must include the procedure in the power unit approval dossier.
This change indicates close monitoring of the issue by the entity.
Implications for manufacturers
The allegations remain officially unconfirmed.
Ferrari, Honda and Audi invoke an article that requires total compliance at all times of competition.
If the interpretation is considered valid, rivals would face difficulty compensating for the advantage in the short term.
If the FIA judges a violation, Mercedes and Red Bull would need to quickly redesign components.
Manufacturers involved in the 2026 era
Mercedes supplies units to its own team, McLaren, Williams and Alpine.
Red Bull Powertrains meets Red Bull Racing and Racing Bulls.
Ferrari equips its team, Haas and Cadillac.
Honda exclusive partnership with Aston Martin.
Audi develops its own project for Sauber.
Cadillac will enter as a new supplier in the near future.
Compliance Procedures
Specific article regulates maximum geometric compression ratio at 16:1.
October clarification specified room temperature runs.
Recent document transfers details of methods to manufacturers, with mandatory approval.
Controls aim to prevent imbalances at the beginning of the new regulatory era.
The 2026 season introduces an almost equal split between combustion and electrical power, with sustainable fuels.
