F1 has not used the word "engine" for a decade. The power unit is a system: a combustion engine, a turbocharger, an electric motor-generator, a battery and the electronics that control them. The 2026 rules rebuilt that system around a much bigger electric share.
What changed
- Combustion engine: still a 1.6-litre turbocharged V6, but cut from roughly 550 kW to around 400 kW, mainly through less fuel flow.
- MGU-K: the motor-generator on the rear axle nearly triples, from 120 kW to 350 kW.
- MGU-H removed: the unit that recovered energy from exhaust heat via the turbo is gone. It was complex, expensive and irrelevant to road cars.
- Fuel: 100% advanced sustainable fuel, made from non-food biomass, waste or captured carbon. Fuel is now limited by energy content rather than mass.
Harvesting and deploying
The MGU-K works both ways. Under braking it acts as a generator, turning the car’s speed into stored charge; on the throttle it drives the wheels. It can recover around 8.5 MJ a lap - roughly double the old system - and does so not only under braking but while coasting, on part throttle, and by taking some combustion power at full throttle to charge the battery ("super-clipping").
The battery itself is small, so at 350 kW it empties quickly. A lap is a cycle of recovering energy and choosing where to spend it, and drivers and engineers plan that cycle the way they plan tyre use.
Why the electric power fades at speed
To stop cars running out of charge halfway down every straight, the rules taper electric deployment above about 290 km/h, falling to zero at 355 km/h. Overtake Mode relaxes that taper for a chasing car - which is exactly why it works.
Who makes them
The new rules attracted new manufacturers: Audi entered with its own team, and Ford partnered Red Bull. A manufacturer that falls well behind can be granted extra development under the ADUO scheme, so one bad design does not lock a team out for years.