Mercedes' 2026 Powerplant Performance Leaves Williams Impressed and Slightly Astonished

Any PU Manufacturer intending to supply a Power Unit to an F1 Team during a Championship (year N) must: a. Declare to the FIA, before 1 August of year N-1, that they provided to their customer F1 Teams: i. An initial full external space model of the Power Unit including details and locations of all physical interfaces required by the team to install the Power Unit. ii. Preliminary estimates of important operating parameters such as heat rejection, fuel mass and density, clutch shaft stiffness and engine stiffness. b. Declare to the FIA, before 1 November of year N-1, that they provided to their customer F1 Teams: i. A final full external space model of the Power Unit including details and locations of all physical interfaces required by the team to install the Power Unit. ii. Firm predictions of important operating parameters such as heat rejection, fuel mass and density, clutch shaft stiffness and engine stiffness. iii. Initial details of any other parts, procedures, operating conditions and limits or any other information required by the team to install and operate the Power Unit as intended. After the 1 August of year N-1, any significant change compared to previous communication, must be notified to the customer F1 Teams in due time. Should a Customer Team consider that the change has an unreasonable impact on the Power Unit installation in the car, they may contact the FIA within 7 days of the notification. The FIA will then contact the relevant PU Manufacturer and its customer F1 Teams in order to conduct its investigation. If the FIA is satisfied, in its absolute discretion, that these changes are acceptable, the FIA will confirm to the PU Manufacturer and the customer F1 Teams within 14 days that they may be carried out.

Components supplied as TRC or FSC must be identical to those used by Supplying Team in same or previous Championship. Bespoke TRC/FSC for specific Customer Team not permitted. Customer Team may modify sub-components with required R&D.

The following additional constraints apply to the permitted modifications discussed in this Article 3: a. To carry out modifications under the provisions of Articles 3.5, 3.6 and 3.7 of this Appendix, PU Manufacturers must apply in writing to the FIA Technical Department and must provide all necessary supporting information including, where appropriate, clear evidence of failures. The FIA will circulate the correspondence to all Power Unit Manufacturers for comment. If the FIA is satisfied, in its absolute discretion, that these changes are acceptable, they will confirm to the Power Unit Manufacturer concerned that they may be carried out. Wherever practical, such requests must be submitted at least 14 days before the requested date of homologation. The procedure and associated document templates that must be used by the Power Unit Manufacturers for their requests are available in the document FIA-F1-DOC-C047. b. Any permitted modifications concerning parts that are inside the sealed perimeter (i.e. parts described as "INC" in the "Sealed Perimeter" column of Appendix C4) can only be applied to new Power Unit elements. c. With reference to the FIA F1 Regulations - Section B [Sporting], if a Power Unit Element is subsequently replaced by another of a different specification between the Sprint Qualifying Session and the Sprint Session or between the Qualifying Session and the Race, the replacement Power Unit part will be considered the same in design and similar in mass, inertia and function if any differences it contains are limited to components modified under the provisions of Articles 3.6, 3.7 and 3.8 of this Appendix. d. A Customer Team may refuse or request a delay of a Power Unit modified under the provisions of Articles 3.3, 3.6 and 3.7 of this Appendix if such modifications cause installation issues in their car. In such cases, the Customer Team must apply in writing to the FIA Technical Department and must provide all necessary supporting information. If the FIA is satisfied, in its absolute discretion, that the installation issues are genuine, they will confirm approval to the Customer Team and to the PU Manufacturer. In this case, the provisions of (e) below won't apply. e. The first time one or more Power Units comprising modified parts, as permitted by Articles 3.3 and Article 3.6 of this Appendix, are used in any of the cars powered by the Power Unit Manufacturer, a minimum of 1 Power Unit with the exact same specification must be available for each F1 Team. Each F1 Team will have priority use of one of these Power Units until the end of the first day of the Competition. In the case of a Manufacturer supplying Power Units to more than 2 F1 Teams, one exception per Championship season can be granted by the FIA, in its absolute discretion, in the event of genuine supply issues. The request must be made in writing to the FIA Technical Department and must provide all necessary information and evidence of the supply issue. If the FIA is satisfied, the minimum required number of Power Units available for all F1 Teams may be reduced to 2 for the Event where the modified part is used for the first time. f. Any new Power Unit element used for the first time in a Competition must always include all modifications included in any Power Unit element already used by any of the cars powered by the PU Manufacturer. g. The requirements of e. and f. don't apply to minor modifications as defined in 3.7. h. A Power Unit element will be deemed to have been used once the car's timing transponder has shown that it has left the pit lane.