FIA Resolves Engine Compression Dispute with Phased Regulatory Adjustment
Formula 1's regulatory body has brokered a settlement concerning engine compression ratio specifications, implementing modifications in two phases. The first adjustment takes effect on June 1, with an additional regulatory shift planned for 2027.

The FIA has moved to settle a contentious dispute over engine specifications by announcing a compromise solution that addresses compression ratio regulations through a staggered implementation schedule.
Under the agreement, the first regulatory modification will come into effect on June 1, providing teams with a near-term adjustment to their power unit specifications. A subsequent change to the regulations has been scheduled for 2027, signaling the sport's intention to manage this technical matter across multiple seasons.
The phased approach appears designed to give all competitors adequate time to adapt their engine development programs while resolving the disagreement that has centered on compression ratio parameters within Formula 1's current technical framework.
Original source
ESPN F1
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 1.2
Homologation dossier contents
Chapter: Appendix C5
In Simple Terms
Before a team can use a new power unit in F1, they need to submit a complete package of paperwork to the FIA. This package must list every major power unit component, all the smaller parts, and other required documents following a specific FIA template (FIA-F1-DOC-C047). Think of it as getting your engine approved before you can race.
- Teams must document all Power Unit (PU) Elements - the major components like the engine, turbo, and MGU systems
- A detailed list of Minor Parts must be included - smaller components that make up the power unit
- All submissions must follow the official FIA-F1-DOC-C047 format and template
- This homologation process is the approval system that ensures all power units meet F1 regulations
Official FIA Text
Dossier must include details of all PU Elements, detailed list of Minor Parts, all required documents, submitted per FIA-F1-DOC-C047.
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.
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