Engine Manufacturers and FIA Agree on Compression Ratio Measurement Overhaul
Formula 1's regulatory body and all power unit manufacturers have reached consensus on revised procedures for measuring engine compression ratios, with the new protocols set to take effect from 1 June. The adjustment applies to the current generation of V6 combustion engines, which currently operate at a 16:1 compression ratio.
In a unanimous decision that signals strong alignment between the sport's technical stakeholders, the FIA has confirmed that all of Formula 1's engine manufacturers have endorsed modifications to the compression ratio testing methodology. These procedural changes will be implemented starting 1 June, marking a significant shift in how the sport monitors this critical engine parameter.
The compression ratio—a fundamental measurement indicating the degree to which an air-fuel mixture can be compressed within a cylinder—sits at the heart of the current power unit specifications. For the ongoing generation of V6 combustion engines competing in Formula 1, manufacturers have standardized this specification at 16:1.
The agreement represents a collaborative effort between the FIA and the manufacturers' contingent, reflecting the governing body's commitment to maintaining consistent technical standards while accommodating input from the teams responsible for power unit development. By securing unanimous backing before implementation, the FIA has ensured that the revised measurement protocols will be accepted across the grid without controversy.
The timing of the 1 June rollout allows teams and manufacturers adequate preparation time to adapt their testing procedures and equipment to align with the new requirements, ensuring a smooth transition as the 2026 season progresses.
Original source
Autosport
Related Regulations
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Full Regulation Text
Article C5.4.3
Geometric compression ratio limit
Chapter: C5
In Simple Terms
F1 engines have a limit on how much they can compress the air-fuel mixture inside each cylinder. No cylinder is allowed to have a compression ratio higher than 16.0, which means the mixture can be squeezed to no more than 16 times its original volume. Manufacturers measure this themselves following FIA guidelines.
- Maximum compression ratio of 16.0 applies to every cylinder in the engine
- Compression ratio measures how much the air-fuel mixture is squeezed before ignition
- Each engine manufacturer is responsible for measuring and verifying their own compression ratio
- Measurements must follow FIA-provided guidance to ensure standardization
Official FIA Text
No cylinder of the engine may have a geometric compression ratio higher than 16.0. The procedure to measure this value will be detailed by each PU Manufacturer according to FIA guidance.
Article 2.2
2026 Power Unit Regulations
Chapter: Chapter II - Power Unit Changes
In Simple Terms
2026 brings major engine rule changes. The complex MGU-H is removed to cut costs and attract new manufacturers. To compensate, the MGU-K becomes much more powerful and the battery is bigger. The goal is simpler, more sustainable power units that are still cutting-edge.
- MGU-H removed from power units
- MGU-K power increased significantly
- Larger energy store capacity
- Aims to attract new manufacturers
Official FIA Text
For 2026, the power unit will comprise a 1.6 litre V6 turbocharged internal combustion engine with a significantly enhanced electrical component. The MGU-H will be removed. The electrical power output will increase substantially with a more powerful MGU-K and larger energy store.
Article 5
Conformity with the power unit homologation dossier
Chapter: APPENDIX C5: HOMOLOGATION AND DEVELOPMENT OF POWER UNITS, FUEL AND OIL FOR 2026-2030
In Simple Terms
F1 engines must be built in a way that allows the FIA to put official seals on them for inspection. The engine manufacturer and teams using that engine must prove to the FIA at any time that their engine matches the original approved design specification.
- Power units must be designed to allow FIA seals to be fitted for verification purposes
- Both engine manufacturers and teams must cooperate fully with FIA technical inspections
- Teams must demonstrate engine conformity with the homologation dossier whenever the FIA requests it
- The FIA has absolute discretion to demand compliance checks at any competition
Official FIA Text
All Power Units must be delivered such that the seals required under Article B8.2.9 can be fitted. Both the Power Unit Manufacturer and users of a homologated Power Unit must take whatever steps are required at any time by the FIA Technical Department, in its absolute discretion, to demonstrate that a Power Unit used at a Competition is in conformity with the corresponding Power Unit homologation dossier.
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