Formula 1's car design revolution for 2026 is the biggest in a generation. Not only are the chassis designs and aerodynamic shapes changing, but for the first time since 2014, the engines — the beating heart of each car — have also been overhauled. It is rare for F1 to change both the car aero designs and the engines at the same time. The sport went through big aero rule changes in 2017 and 2022, but the engines went untouched — until now.

The engines remain hybrid units, combining combustion with electrical power, but there have been considerable changes in how they function. Electrical power has increased, and fully sustainable fuels have been introduced. While engine performance across manufacturers has largely been balanced in recent years, the 2026 changes could deliver significant, potentially decisive gains. In 2014, when F1 first introduced hybrid engines, Mercedes emerged with by far the best, setting it on course for eight consecutive world championship wins through to 2021. That is why F1's engine manufacturers — Mercedes, Ferrari, Red Bull/Ford, Honda and Audi — have spent years preparing for this change. Getting it right now could take years to overcome.

What's changed on F1's 2026 engines

The 2026 engines are not too dissimilar to their predecessors in their core make-up. They are still 1.6-liter V6 hybrids, combining the internal combustion engine and a battery. But there has been a significant increase in the amount of electrical power available through the hybrid system, which has also been simplified and will become a substantial area of focus for drivers and teams this year.

The previous engines used two energy sources to recharge the battery: the MGU-K (K stands for kinetic energy) and the MGU-H (heat). Together, these provided around 20 percent of the car's power, with a maximum electrical output of 120kW. For 2026, the MGU-H has been discontinued, as it was very costly and not relevant for most road cars, while the MGU-K has become much more powerful. The electrical output has almost tripled to 350kW, and the power split will now be nearly 50-50 between the internal combustion engine and the hybrid system.

Why drivers will need to be smarter

Moving to a near 50-50 split between internal combustion and battery power in 2026 will significantly affect how the new cars are driven and how everyone races. The drivers have an extra tool available to them this year to make use of the additional electrical energy. Overtake Mode replaces DRS as the main overtaking assist, providing extra power from the battery when a car is within one second of another ahead. There is also Boost Mode, which drivers can use at any time around a lap to engage maximum battery power, either to attack or defend.

But the increased power and reliance on the hybrid system mean the drivers will now need to work harder than before to harvest energy and recharge the battery. They can do this by lifting off the throttle and braking to engage the MGU-K, and much of the regeneration will be automated by the engine's control unit. There may be new tactics that could help, such as running at maximum revs through a corner or even dropping to first gear — a rarity on an F1 track — in a bid to harvest more energy by maximizing engine braking when slowing the car. It also means the quickest way around a lap will not be to use maximum power at all times, as that would drain the battery.

Mark Temple, McLaren's technical director for performance, told reporters that drivers would "need to use energy more intelligently, more strategically, around the lap. (There is) a need to harvest energy more consciously and then choose where you use it."

Although the cars will be slower overall than the previous generation due to reduced downforce under the new aero rules, which slows cornering, the extra battery boost will make them quicker exiting corners and reaching top speeds on the straights. "It's potent on traction and exits, it's potent on recovery at the same time, and there will be games to be played that are a lot more strategic," Williams team principal James Vowles told The Athletic in an interview.

F1's new fuel for 2026

After taking the first step in 2022 to introduce a 10 percent renewable ethanol blend, F1 has now increased to 100 percent sustainable fuel. It is a step toward the sport's goal to reach net zero carbon by 2030, but it has also posed challenges to the engine manufacturers and their fuel suppliers.

Hywel Thomas, the managing director of Mercedes High Performance Powertrains, worked with team supplier Petronas to develop the new fuel. While it may not make much of a difference for fans, Thomas called it a "truly breathtaking" product. "What the regulations (effectively) did was say, 'we don't know how you're going to do this, guys, this doesn't exist in the world. Good luck, but it's going to be 100 percent sustainable. Off you go!'" Thomas told The Athletic. "This is inventing whole new ways of creating these chemicals. So it's a phenomenal task. But also, what a great advert for F1 to say, 'these are the fastest cars in the world, just pour in this fully-sustainable fuel (as well).' We invented that in the last three years!"

Ben Hodgkinson, the technical director of Red Bull Ford Powertrains, said the reason the new sustainable fuels are "a bit tricky" is that the various chemical elements have different evaporation points. This means they must ignite at a higher temperature than in the previous engines. "The old fossil fuels used to evaporate at a bit lower temperature in a very clean, very narrow window, which meant you got vaporization very cleanly," Hodgkinson told reporters. "With sustainable fuels, you get some elements that are evaporating later than others, and it can be a bit of a challenge with combustion (to produce power)."

The hope is that the technology used in the 'drop-in' sustainable fuels — so-called because they can be dropped into any internal combustion engine — can transfer to the broader automotive industry.

Why 'integration' between chassis and engine matters

A word that has been used regularly by F1 engineers and team personnel when discussing the new engines is "integration" — how the engine will function in tandem with the car's aero, which will be more critical than before due to the increased emphasis on efficiency during harvesting and subsequent battery use. New features like active aero (flaps that open on the front and rear wings) help forge a much closer relationship between the engine and the chassis around it, reducing the energy needed to reach top speeds by automatically shedding drag in corners and on straights. Battery power will be the key compensator for additional drag (and therefore loss of speed) that teams can eliminate in their car designs.

"(The integration aspect) is going to get ramped up massively," Thomas said. "That's really exciting for us."

This could put the 'works' teams, which produce their own engines rather than buying them from others, at an advantage. These squads (Mercedes, Ferrari, Red Bull, Audi and Aston Martin via Honda) know the exact dimensions of their engine and can integrate it seamlessly into the chassis shapes without compromising the internal packaging that some customer teams may face. Red Bull is one team that hopes to reap the benefits after it opted to embark on its own works program together with Ford, establishing a new engine division at its F1 headquarters in Milton Keynes, UK.

"I've tried to exploit that as best as we possibly can," said Hodgkinson. "There are definitely choices that we've made that are different (compared to a customer team), because the real-time decision that we can make is just different to when your power unit supplier is even only 30 miles away."

A tighter set of engine rules

When F1 last overhauled the engine regulations in 2014, a significant split in approaches led to significant performance differences — the bedrock of Mercedes' streak of championships, as its MGU-H was initially much better than the system used by its rivals. A similar split through the field is unlikely in 2026. Not only is this the first overhaul of the hybrid rules since F1 introduced a cost cap, but the regulations have also been written to limit how much designs can vary.

"There are far more constraints within the combustion engine regulations, max valve sizes and positions," explained Thomas. "We've (also) got standard fuel injectors. There's quite a lot that's gone into trying to reduce the envelope to change."

Although such limitations may frustrate F1 engineers, who would love a blank sheet to work from, this should prevent a big spread in performance and avoid forcing manufacturers to play catch-up by spending heavily, even more difficult under a cost cap, just to regain ground. "It is a lot more restricted," said Vowles. "Do I think there will be visible differences between power units? Probably at the beginning, yes. But with the right mechanisms in place to allow others to catch up, so you have a field that's coming together."

But the tighter rules haven't stopped teams from finding innovative ways to try to maximize performance. Mercedes and Red Bull have reportedly found a loophole in the engine-compression ratio rules that has sparked questions from rival teams, as it's believed that what they are doing could provide an engine power increase.

What it all means for F1

The 2026 season is a big reset for F1. When it comes to defining this new era — 2022-2025 was all about aero, via the ground effect principle — the engines will be critical. So much work has gone into producing them; this again puts their performance in the spotlight after years of relative parity. But the fact that drivers will need to change their approaches as well and become smarter in their use and recovery of battery energy makes this a shift that will be felt all the more sharply in the cockpit. It is an art the drivers must master, but something that should quickly become second nature.

The early feedback from testing in Barcelona has been largely positive. "There was a lot of anticipation for these new power units, and generally, the amount of power that they give is pretty impressive," Mercedes' George Russell told F1TV after the first day of testing. "I think for all the cars I was watching today, with all the different power units, it was probably the quickest I've seen an F1 car pass here in Barcelona. That was pretty exciting to see."