Why F1 slammed the brakes on a return to V10s

“Every age has its peculiar folly – some scheme, project, or phantasy into which it plunges, spurred on either by the love of gain, the necessity of excitement, or the mere force of imitation.”

Those words were first committed to paper almost 200 years ago by the Scottish author Charles Mackay in his seminal tome Extraordinary Popular Delusions And The Madness Of Crowds and they resonate with truth to this day. Mackay chronicled subjects as diverse as the South Sea Bubble, Dutch tulip mania, the Crusades, Witch mania, alchemy – and, perhaps most intriguing of all, ‘the influence of politics and religion on the hair and beard’.

Were Mackay writing today, he would no doubt have raised an eyebrow, followed by his quill, at recent political developments in Formula 1. As the first five rounds of the 2025 season played out, F1 was gripped by a mania.

The idea of returning to naturally aspirated V10 engines, floated in private by former ‘ringmaster’ Bernie Ecclestone and then in public by FIA president Mohammed Ben Sulayem, first gained traction, then acquired seemingly unstoppable momentum.

By round two, in China, even usually sensible paddock insiders were whispering that the forthcoming 2026 hybrid-turbo power unit regulations could be junked in favour of a clean-sheet naturally aspirated concept.

As the German philosopher Friedrich Schiller memorably said: “Anyone taken as an individual is tolerably sensible and reasonable – as a member of a crowd he at once becomes a blockhead.”

The final all-V10 grand prix was China 2005, won by Renault

Photo by: Sutton Images

As the hysteria mounted, even some of those who had set it in motion began to grasp the enormity of their actions and engaged reverse gear. In a crunch meeting ahead of the Bahrain Grand Prix, attended in person by the likes of Honda Racing Corporation president Koji Watanabe, and virtually by such as Mercedes-Benz chairman Ola Kallenius, sense prevailed and the notion of a return to natural aspiration was pushed forward to an unspecified point in the future.

But where had the notion come from in the first place, and why did it so quickly gain momentum? It’s understood that one of the long-standing team principals produced his phone during the F1 Commission meeting on the morning of the F175 launch at London’s O2, and announced that Bernie Ecclestone was on the other end of the line. Even on speakerphone, that unmistakeable almost-whisper conveyed clarity and authority: “Bring back V10s.”

Later that evening the arrival of the FIA logo on the giant screens prompted thunderous booing in the arena, causing the governing body’s famously sensitive president to chafe.

“Any new regulation always comes with a degree of fear and a degree of uncertainty. And there’s always a risk with a new regulation” Nikolas Tombazis

Within hours Ben Sulayem had donned his rose-tinted spectacles and was thinking out loud, via Instagram, about a return to V10s powered by sustainable fuels – populist dynamite given the widespread dissatisfaction with the current hybrid-turbo powertrain’s lack of noise and visceral appeal.

There is a reason the ground was tinder-dry, ready for this bushfire to let rip. Fear has been spreading through the teams and drivers that the 2026 regulations would be a bust, for two key reasons: the first is that, while the removal of the complex and expensive-to-perfect MGU-H element of the hybrid system, along with the proposed 50/50 split of power between electrical deployment and the internal combustion engine, has attracted new manufacturers, early simulations suggested that the electrical power would run out on long straights.

Secondly, and more prosaically, word has been circulating that Mercedes is well ahead of its rivals on power and reliability. Memories of 2014, when the current hybrid rules were introduced and Mercedes ran away with the championship, remain terrifyingly fresh.

Tombazis believes that all will be well with the new ruleset

Photo by: Formula Motorsport Ltd

“Any new regulation always comes with a degree of fear and a degree of uncertainty,” says FIA head of single-seaters Nikolas Tombazis. “I don’t think one can ever claim completely that there’s none of that, and there’s always a risk with a new regulation. Somebody messes up initially and does something less well than others or whatever.

“That’s part of the game, both for the strategy and for the technical. When the new 2022 regulations started, we had a huge number of doubters saying, ‘Well, they will never work, they will all be bad and disastrous’ and so on.

“And I think that was quite disproven, and equally we were reasonably lucky early on in those regulation cycles that Ferrari and Red Bull were quite evenly matched, so it created a nice momentum initially because they were fighting.

“Red Bull pulled ahead and then obviously lost the advantage. The same can happen on any new regulation. It’s also important to remember that if we didn’t have those regulations we’d be looking into a situation where we’d have only two PU manufacturers in F1 at the moment. So we’d have half the teams on Ferrari engines and half the teams on Mercedes engines. And we don’t think that’s conducive for good sport.

“So we’ve made quite a level of simplification in the engine regulations. Not as much as we would like – the FIA would have liked to go a step further. We try to find consensus. But we’ve made nonetheless a lot of simplification compared with the current engines.”

While the FIA has been evaluating active aerodynamics and reduced downforce to counterbalance possible power issues – and enable the cars to run closer to one another on track – drivers expressed great dissatisfaction after those early simulator runs.

Few want a return to the kind of domination enjoyed by Mercedes in 2014

Photo by: Steven Tee / Getty Images

Tombazis argues that this was always likely to be the case, given those simulations took place so early in the development cycle. “We’ve been carrying out a huge number of simulations on scenarios of how people deploy their energy,” he says. “We’ve been refining and we have a bit more refinement to do. So I don’t think the cars will feel unnatural as some people suggest.

“Drivers naturally evaluate preliminary versions of cars when things are being developed and they get maybe a snapshot of something they’re not used to – and they can jump to conclusions a bit early. Generally speaking, a driver will never step out of a car of a certain regulation cycle and into a new car with, say, less downforce, and say, ‘Well, I like it’.

“We expect the new regulations to have maybe a CL [coefficient of lift] of between half and one less than the current CL. So approximately, say, 20% less downforce, give or take – we don’t know exactly. If you give that to a driver the initial reaction is always going to be potentially negative. And that was the case also for the 2022 regulations.

Influential figures within the paddock who are paranoid about the prospect of a new era of Mercedes dominance have been frantically stirring the pot

“So I don’t think that should be the main point of focus. We believe 2026 is the right package to bring more participants to the sport. We believe it by the virtue that it has increased electrification.”

The debate has taken on a significant political dimension with the FIA insisting it is acting for the commercial and sporting health of F1, while influential figures within the paddock who are paranoid about the prospect of a new era of Mercedes dominance have been frantically stirring the pot – and mobilising a fanbase still misty-eyed about the halcyon days of screaming engines.

Mercedes, naturally, stood its ground at the Bahrain meeting – with support from Honda, Audi, Ford and Cadillac representatives. Ferrari could afford to remain agnostic since its presence in F1 is not contingent on the specific mix of hybrid power.

Honda’s RA109E allowed McLaren to dominate the 1989 title race

Photo by: Paul-Henri Cahier / Getty Images

What all the other parties apart from Mercedes were looking for was a mechanism by which they could be allowed to catch up if they start next season with a power deficit – there is no appetite for a repeat of Honda’s well-publicised struggles in the early stages of its hybrid project.

Once this principle was agreed, a consensus was also reached on the question of a return to natural aspiration – it was to be kicked down the road. A press release followed, emphasising the commitment of all the stakeholders to the 2026 regulations, with a noncommittal addendum to the effect that naturally aspirated engines with some form of electrical boost could be considered in future.

That might be as late as 2031, when the next set of regulations is planned to come into force, or it could be earlier depending on which way the competitive and economic winds blow. The 2026 rules have been in development since Jean Todt was FIA president, a time when governments all over the world were pushing car manufacturers to drop internal combustion engines entirely.

Since then – even since the likes of Audi and Cadillac were enticed to join, and Honda decided to stay – the move towards wholesale electrification has lost momentum in the face of widespread consumer resistance. Politically the issue of ‘net zero’ has become divisive, not to say incendiary in some quarters.

So the sensible path is to maintain a public consensus on supporting the 2026 package and making it work, while waiting to see whether sustainable fuels grant the internal combustion engine a stay of execution in the wider world.

To a large extent this depends on resolving production scale issues, since the demand for aviation fuel – rather more necessary for global trade and business – is expected to account for the majority of supply for the foreseeable future.

Current rules in 2022 featured early battles between Ferrari and Red Bull

Photo by: Zak Mauger / Getty Images

But despite the fresh agreement over making the 2026 package work, there are still potential shortcomings to iron out. As many critics of the base concept pointed out – prior to being shushed – many elements of the car package, including the active aerodynamics, are in place to mitigate potential shortcomings in the PU’s electrical deployment.

What those early simulations revealed was that at some tracks – Monza, for instance – there are insufficient opportunities to charge the battery over the course of a lap.

This risks power units experiencing a ‘de-rate’ on long straights – running out of electrical charge. One of the FIA’s proposed solutions has been to introduce rules governing the battery’s ‘ramp rate’, the speed at which it deploys energy, to reduce the possibility of drivers using too much electrical energy at corner exits. Again, though, this is mitigation.

The 2026 regulations have been pulled in so many directions, by so many parties with conflicting interests, that the result was bound to be open to criticism

Another proposal evaluated at the most recent F1 Commission meeting, after the Saudi Arabian Grand Prix, was to keep the 50/50 power split for qualifying but shift to 64/36 in the internal combustion engine’s favour for races. This would amount to reducing battery deployment from 350kW to 200kW, a more sustainable figure.

Currently the ratio is 85/15 and the electrical input is capped at 120kW. Mercedes team principal Toto Wolff thundered that even considering this proposal was “a joke” – but then, given the supposedly advanced state of his 2026 power unit, he would say that, wouldn’t he?

In effect, the 2026 regulations have been pulled in so many directions, by so many parties with conflicting interests, that the result was bound to be open to criticism, despite the FIA’s efforts to reconcile all the inputs into a raceable package.

Wolff has not concealed his anger at talks over engines

Photo by: Peter Fox / Getty Images

Tombazis insists that the racing will be competitive even if the weight saving of the new cars over the previous generation is a modest 30kg: “In the 2021 regulations, cars following closely behind another would be maybe at 60% downforce [owing to effects of wake turbulence]. When we started the 2022 regulations, we were probably at 80% or so. That gradually got eroded to what is now 70 or 65% or something like that.

“We believe the new regulations takes us back to around 90%, so much better than the start of 2022. In addition, we believe we’ve made them more resilient to loopholes. The reason there’s been this erosion now is because we were a bit too permissive in some areas and we left some space, which we believe we’ve learned from and we’re trying to avoid for 2026.”

Provided the spectacle is sound next season, the criticisms may fade, but the nostalgia for naturally aspirated temps perdu will continue to bubble away in the background. One of the prime causes of F1 cars bloating over the past decade or so has been the hybrid power units and the proliferation of cooling systems they require, all of which have to be aerodynamically optimised.

Naturally aspirated engines would likely be lighter, and cheaper to develop, even if a hybrid element is included. That would improve agility and you would see the cars more eager to turn. But would they be as loud as before? Most likely not. Modern health and safety considerations militate against the high-frequency shriek of a V8 running at 18,000rpm, as does the requirement for engines to last more than two or three race weekends.

Whatever happens in the coming months, there will be no going back.

This article is one of many in the new monthly issue of Autosport magazine. For more premium content, take a look at the June 2025 issue and subscribe today.

Renault-powered Benetton, driven in 1995 to glory by Michael Schumacher

Photo by: Sutton Images