F1 2027 engine regulations: how and why the power unit rules are changing

The 2026 Formula 1 season is far from over but officials have already admitted that the all-new engine rules, introduced this year, have some serious flaws.

Designed to use more electric power and less fuel, Formula 1’s new power unit regulations have attracted new manufacturers. They’ve also attracted plenty of criticism too, and there are a raft of changes planned for 2027.

Technical adjustments will reduce reliance on electrical energy, but will also result in shorter races — a move that has just been approved by racing’s governing body.

Here’s how the powertrain rules are changing in 2027 and why it’s phase one of a longer fix.

What’s actually gone wrong?

The 2026 rules required F1 engine manufacturers to develop brand new hybrid power units, which produce roughly half their power from an internal combustion engine (ICE) and the other half from electrical power. Although F1 has used hybrid engines since 2014 (a year Mercedes also dominated), this is a huge change from last season, when only 20% of power was supplied by electric motors.

This year, at most circuits, F1 car batteries can’t store enough power for a full lap at race speed, so drivers are managing battery levels by going slower than they normally would; braking earlier for corners to generate electricity; or even sacrificing performance to generate electricity from the engine. Much of the hybrid system is computer-managed, so drivers don’t full control on where to use the power.

Worse still, on Saturdays, the new rules have moved qualifying away from the all-out driver challenge it used to be.

The new-for-2026 power units have an ICE producing 400kW and an electrical system, providing 350kW. Over the course of a typical lap, around 53% of the energy comes from the ICE, around 47% from the electric motor.

Last season’s cars produced around 120kW from their electrical components, so the ICE was doing around 80% of the work.

Despite the boost in electrical power, the maximum battery size hasn’t increased: F1 batteries only store up to 4MJ of energy, which is a fraction of what’s needed each lap.

Although batteries can be recharged multiple times, using braking energy or ICE power — up to a maximum of 9MJ per lap —this is still not enough to drive flat-out on many circuits, particularly during qualifying.

It means that electrical power is sometimes rationed to sections of the circuit where it’s most effective — such as at the start of long straights. On shorter high-speed sections, cars may only be driving on 50% of their power (using the ICE only), or even less if they are using their ICE as a generator — a process known as super-clipping.

This can be dangerous where teams have different deployment models: one car could be trundling on half-power, while the other is at maximum attack. This scenario has already seen Ollie Bearman crash at 191mph during the Japanese Grand Prix, when he drove up behind Franco Colapinto who was going 30mph slower.

Even when it’s not dangerous, it’s created what fans and teams are calling ‘yo-yo racing.’: one driver uses power in one part of the lap to overtake, while the other deploys it elsewhere to retake the place. It might produce more passing, but the result is confusing and artificial.

Once fans saw the result in the opening races of 2026, there was an outcry (although many were in favour of the increased overtaking) and F1 introduced a mid-season ‘patch’ ahead of the Miami Grand Prix weekend in May, which addressed some of the issues.

Officials were given the ability to reduce the maximum recharge limit by 1MJ per lap in qualifying. At the same time, the recharge rate was raised from 250kW to 350kW in qualifying. That meant harvesting – and that awkward slowing down it caused – formed a lower percentage of the lap.

In races, MGU-K power stayed at 350kW in key overtaking zones but was limited to 250kW elsewhere, to reduce the performance discrepancy between cars on full charge and those without any battery energy.

Those changes had a moderate effect, but the 2027 ones will go further.

What’s actually changing for 2027?

The new rules in 2027 will adjust the ICE/electric power split, so that the ICE contributes 58% of the power, and the electric motor provides 42%, reducing recharging demand and the performance impact when batteries are empty.

That will shift again in 2028, when the split becomes 60/40 in favour of the ICE. That still leaves the electric motor doing around twice as much as it did pre-2026.

The rules achieve this new split by increasing the maximum ICE output from 400kW to 420kW next year and up to 450kW in 2028.

Engines won’t need to be redesigned because the extra power is gained by increasing the fuel flow by 5% in 2027 and 13% (compared with 2026) in 2028.

Maximum electrical deployment drops from 350kW to 300kW and stays capped at that through both seasons. However, overtake mode, the electrical replacement for DRS, remains at 350kW so drivers have something more to play with tactically.

Harvesting power moves from 350kW to 375kW in 2027 and 400kW the year after, which will further reduce the time spent charging batteries.

There’s one further change: the increased fuel flow means that cars will now use more fuel per race than before. Instead of forcing teams to develop slightly larger fuel tanks to account for this – not ideal during the cost-cap era – Formula 1 is shaving distance off each race. The standard race distance will reduce from 305km (190 miles) to 290km (180 miles), cutting two or three laps off most grands prix.

The timescale

The new rules come into force in 2027. The season’s 24-race calendar features a record ten sprint races, and will open with a pre-season test that could be four days instead of three.

The current power unit architecture is scheduled to run until 2030, and the FIA wants agreement on what comes after locked in before the end of this year. The most public and obvious choice appears to be sustainably-fuelled V8 engines, but between now and then, Formula 1 will try to fix its new hybrid regulations.

What it means for the championship fight

The power balance between the powertrains is shifting all the time, but if the 2027 rules were to arrive tomorrow, they would be likely to favour teams with strongest ICE unit.

Red Bull‘s combustion engine was ranked the most powerful by the FIA earlier this year — as part of its ADUO process to prevent one power unit manufacturer from dominating the series, while Mercedes is undoubtedly strong too. The others, including Ferrari, Honda and Audi, will need to spend their engine upgrade tokens (awarded by the ADUO process) wisely if they want to mount a title challenge.

Will it work?

The theory is sound: increasing the fuel flow rate and reducing the reliance on electrical energy is the approach that many experts, including Motor Sport F1 editor Mark Hughes, had urged.

While energy management will still be needed, the 2027 F1 rule changes look to be a step in the right direction, even if it does come at the cost of a few laps of racing.”