While the outcome of a vote on changing Formula 1’s engine compression tests will not be known until next week, the expectation is that it will get passed.
With Mercedes’ rivals having agreed on a hot test procedure they think should be implemented, and the FIA understood to be in favour of getting a line drawn under the ongoing controversy before the season-opening Australia Grand Prix, the necessary 'super majority' is in play.
Four of the five manufacturers are in alignment so, with the FIA and FOM likely on side too, Mercedes will be powerless to stop the changes going through.
But even now the next steps and outcome seem clear with the FIA having gone public with its e-vote plans, what is less clear is the potential impact on the competitive picture that the new hot test will have.
And there is even a scenario in play where, rather than Mercedes and its customers being the ones that lose out here, they could find themselves in a position where any advantage they have is not cut down at all.
Season of two halves?
An agreement over a new test procedure from August 1 still means nothing is going to change in the short term.
Mercedes, McLaren, Williams and Alpine can all head to the Australian Grand Prix, as well as the first 13 races of the year through to Hungary, safe in the knowledge that their power unit fully complies with the regulations as written for the compression ratio.
Mercedes boss Toto Wolff has said a few times that his squad consulted with the FIA throughout the design phase of the power unit to ensure its interpretation of the rules was in line with what the governing body felt.
And with F1’s technical regulations having changed in October to make it explicit that compliance checks for the 16:1 ratio will be done at "ambient" temperatures, it is clear Mercedes’ approach will not face any FIA headaches with the rules as they stand.
Furthermore, it has become apparent that the potential for a protest over the matter – which emerged as a scenario last December when the story first flared up – has faded away.
This is as a consequence of both the way the situation has developed to implement the new test procedures and Mercedes’ rivals admitting that more important to them is getting an answer on what is and is not allowed.
As Red Bull team boss Laurent Mekies said in Bahrain on Wednesday: “We don't really mind if the regs go left or if the regs go right.
“What we absolutely want is clarity on what we can do and what we cannot do.”
Approval of the new test procedures will give such clarity on a timeline for development now, and stop the compression ratio row overshadowing the start of the season.
Long-term impact
What is more open for debate though is whether the clarity over test procedures for the second half of the year will have any impact on the competitive picture.
It is too simplistic to automatically think that because Mercedes is exploiting compression ratios at high operating temperatures that it will have difficulties passing the hot test.
The FIA has mentioned plans for checks to be conducted at 130°C – but it is not impossible that whatever Mercedes is doing takes place only at temperatures above that.
Should that be the case, then the new hot procedures will not make any difference to Mercedes’ competitiveness, so will have achieved nothing in slowing the it down.
There is also one interesting scenario at play where, rather than the new test helping those trying to catch up, the introduction of an added hot procedure could actually make it more difficult for them to find gains.
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It is unusual for engines to increase compression ratio when running hot – as it is far more typical for it to decrease when running hot.
So the task for anyone wanting to follow what Mercedes has done – once they understand it – was in theory quite simple based on the current tests taking place at ambient temperatures. It was to create a power unit that complied with 16:1 when cold but through clever tricks with thermal expansion, was able to run at a higher level when hot.
Now, however, with both a cold, and a hot test at 130°C, the challenge for anyone wanting to exploit an increased compression ratio is to make sure that whatever they are doing works in both cold and limited hot conditions.
That could require a bigger degree of technological sophistication than just passing the cold test, and could take months to understand, develop and implement.
There is also a matter of timing with the August 1 date having been singled out.
This year, as part of the F1 2026 regulations, engine manufacturers have been given the means to make improvements to their power units if they are well behind.
Under what is known as the Additional Development and Upgrade Opportunities (ADUO) system, those that are behind can implement upgrades, extend usage of test benches and adjust cost spending.
There are three periods - races 1-6, 7-12 and 13-18 – when engine performances will be measured.
If the FIA deems a manufacturer to be between 2% and 4% off the best, then it will be allowed one additional upgrade in-season; if it is more than 4% off by the FIA's test parameters then it will get two upgrades.
But with the first period ending after the Miami Grand Prix in early May, any manufacturer that falls within the 2-4% window set out by the FIA will then face a call on what to do in terms of committing to compression ratio exploitation.
Does it introduce something early that pushes things to the max but could struggle with the new August 1 checks, or does it do something that it knows is good for the long haul?
So rather than the looming compression ratio rule change bringing the flag down on the controversy, it appears instead to have fired the starting gun on even more development headaches.
