Why FIA has given power unit manufacturers August deadline in compression ratio saga

FIA single-seater director Nikolas Tombazis has explained why the F1 2026 power unit manufacturers have been given until August to make changes, should an e-vote result in an amendment to the regulations.

On Wednesday, the FIA confirmed it has launched an e-vote amongst the members of the power unit advisory committee [PUAC] to evaluate  regulatory change to introduce a new compression ratio measurement protocol.

Nikolas Tombazis: Why the FIA has introduced the e-vote

The e-vote is intended to draw a line under an ongoing situation regarding the geometric compression ratio measurement protocols of the power units.

As has been extensively documented recently, the situation focuses on a grey area of the regulations pertaining to measurements being carried out at ambient temperatures.

The five power unit manufacturers [PUMs], as well as the FIA and FOM, make up the PUAC, and the FIA confirmed a 10-day window to cast an e-vote on whether to introduce a regulatory change, introducing a hot operational temperature measurement protocol, should be formalised as a regulation.

The proposal is to introduce this measure into the regulations from August 1st, after the Hungarian Grand Prix, and can only be added if a supermajority, ie. six of the seven members of the PUAC, is formed. If that happens, the matter will be passed to the World Motorsport Council [WMSC] for ratification.

Senior paddock sources have indicated that all five of the PUMs are believed to be able to pass the compression ratio tests, whether carried out at ambient or operational temperatures, but the focus of the speculation has centred on Mercedes High-Performance Powertrains [HPP].

With a decision, one way or the other, set to emerge before the power unit homologation date of March 1, the FIA’s single-seater director spoke to media on Thursday in Bahrain, in which he shed light on how the behind-the-scenes discussions amongst the PUMs with the governing body have played out.

“There are a lot of nuances when discussing such a matter, because there’s what the regulations intend to be,” he said.

“To keep the compression ratio at 16:1 was one of the core objectives, when the regulations were discussed with the PU manufacturers back in 2022 and when they were finalised.

“There’s also a topic of exactly what’s written in the regulation and it became obvious that, what was written in the regulations, there could be ways that one could have a higher ratio.

“So, in terms of whether there’s any discussion of somebody cheating or somebody breaking the rules, that’s never been the topic of the discussion.

“There’s been a lot of emotion on the topic, but there’s never been any position from the FIA that somebody is doing something illegal.

“Do the rules as written achieve fully the objective and general approach when the rules need improving?

“Because, if they don’t achieve fully the objective, we try to make amendments because we want to keep the rules focused on what is the objective and not to be evolving gradually when interpretations maybe stretch them a bit in one or the other direction.”

With the furore kicking off over a winter in which revolutionary new regulations have been introduced, Tombazis said it was inevitable that some grey areas were likely to appear.

“There’s maybe 15 or 20 people dealing with the regulations in the FIA. We have meetings with teams and PU manufacturers and technical directors and so on, very frequently,” he said.

“Each team has 200 or 300 people focused on performance, on design bits, trying to find downforce or performance or whatever. And the same happens for the PU manufacturers.

“It’s unavoidable that, with new regulations, there’s going to be some areas where solutions are found that are beyond what the rules intended.

“So what we’re trying to do with the e-vote is close this topic and hopefully achieve a solution. That is not a unilateral position from the FIA – an e-vote needs people to vote, in this case, the PU manufacturers. And we see what will come out of that.”

Nikolas Tombazis: Compression ratio issue never needed this level of attention

Depending on who discusses the topic, the benefits of being able to run at a higher compression ratio while on track varies – Mercedes’ Toto Wolff has suggested it’s negligible to the point of being two to three horsepower, while Red Bull’s Max Verstappen scoffed this figure and suggested it as being 10 times higher than those.

A feisty appearance from Wolff in the press conference on Thursday indicated the Austrian’s unhappiness with how the matter has played out at the PUAC, saying he “philosophically disagreed” with how the governance structure has essentially isolated Mercedes into a position in which it appears it is set to lose out in the vote.

On Wednesday, Red Bull’s Laurent Mekies clarified that the matter has been more important than “just noise” to his organisation, and stressed how clarity is reached on the issue to ensure all the PUMs know what is and isn’t permitted in the regulations.

For Tombazis, the matter has been overblown out of proportion.

“The process is that, for PU matters, the PU manufacturers vote and, of course, the FIA and FOM. And if that is successful, then it goes to the World Council,” he said.

“So we have a process launched at the moment with the PU manufacturers, and hopefully we’re going to close it.

“Having said all of that, I think that… I’ve been on the other side of the fence, working a team, and people get extremely passionate about performance.

“They’re extremely competitive. The stakes are high, so they get very, very excited.

“When people are so excited, they sometimes tend to lose a bit the perspective of the argument, and they tend to see things slightly one way.

“I have that when I play backgammon with my wife. We forget love, and we sometimes argue about something. It’s extremely competitive.

“Formula 1 is that times 1000, so people get a bit too excited, and I don’t think this topic ever needed to get to that level of attention.

“I’m not saying it’s not important, but I think does it matter to all this excitement for many months? Frankly, no.”

With Tombazis’ stressing that there has never been any suggestion of Mercedes attempting to cheat or that there has been any intentional attempt to maliciously break the rules, the opportunity upon which HPP appears to have jumped could be seen as opportunistic engineering.

In a sport intended to be an engineering and technical meritocracy, rewarding those who spot such opportunities, Tombazis said the intent of the regulation itself does play a part in the approach taken to fixing such a grey area.

“That’s where we need to to be even-handed on this topic,” he said.

“We don’t want to stifle innovation. But, when the regulations state that the parameter has to be below 16:1, it’s not a new combustion system we’re talking about. It’s something that specifically could perhaps increase.

“Now, as I state, I don’t think that we are anywhere near the levels of performance that was stated, and certainly there was no cheat or anything like that, or no allegation of anybody being illegal.

“It is just a matter whether that was an intent of the regulation, and, as new regulations currently enforce, there will be this, but there will be other little topics that we will need to resolve going forward, and the approach will try to be even-handed.

“Each time that we follow something, I’m sure there will be people that are unhappy that we’re not acting soon enough, and there will be people who are unhappy that we are not letting things by, and part of our job is to try to keep that on a on a sort of balanced way.

“People tend to usually remember when something isn’t exactly as they would please and forget when something goes in their way, and therefore that creates a degree of high emotion.”

Why any rule change will only be made in August 2026

As for why an additional compression ratio test is proposed for introduction in August, rather than immediately, Tombazis said an attempt to try forcing through changes on a shorter timeframe would have been unfair on the PUMs.

“We felt it was feasible, because we felt there wasn’t any discussion of anything illegal. We think people have spent time designing their engines and solutions,” he said.

“We didn’t feel it was fair to do something for the start of the season.

“We felt it was wrong, but we also didn’t feel it was something as it was beyond what we felt was the intention of the rules.

“We felt it was correct to also not let it go on too much. There’s a degree of subjectivity there. I can’t say that is the only solution that a human can think of, but we felt it was a balanced approach; as I say, ultimately, we haven’t decided anything.

“We’ve decided to, after a lot of discussions, to launch this vote. The result of the vote will determine whether that thing happens or not.

“If the vote gets approved by the PU manufacturers and by the World Council, then the engines that run from August onwards will have to be legal to that parameter.

“If somebody is beyond that level in Melbourne, then they will have to make adjustments. But I don’t want to comment on what people’s technical solutions are in Melbourne, but I do also stress that I think this matter isn’t really something that is anywhere near as important as people make out.”

With the power units set to be homologated on March 1, shutting down any architectural development or modifications outside of tightly prescribed appendices in the technical regulations, as well as similarly controlled additional development opportunities under the ADUO framework, Tombazis said any affected PUMs will be given permission to make the necessary changes.

“They would have to make some modification, and we approve modifications, and there’s a process for necessary modifications, and, in the appendix which defines a PU homologation, you can see the regulations, there’s also a process for adapting to regulatory amendments, for example,” he said.

“If they need to make some modifications, then obviously we would not force them to not make them and then disqualify them, if you know what I mean, we would allow that.”

Such changes will fall under the power unit manufacturers’ newly-introduced budget cap spending for this year, but Tombazis said he expects changes – if any at all are required – will be minor.

“The level of difference of the compression ratio, if you work out the numbers, take the diameter of a cylinder, the stroke, and see how much we’re talking about, in terms of millimetres, it is extremely small numbers.

“It’s very easy to adjust an engine from one setting to a slightly different setting. We’re not throwing everything away.”

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