2026 Drama: Alleged engine loophole

[richardn]

What can be inferred from this story.

1) The televote was going to be against a rule change.
2) What Mercedes are doing can't be closed off by a simple rule change. "All volumes included in the compressed volume measured as part of the CR must be subject to the combustion process in all conditions", otherwise that would be the proposed solution for next year.
3) The other manufacturers were able to make the case that the rule change as proposed would force them to implement a solution like Mercedes to remain competitive for future seasons and this would be a barrier to entry for new manufacturers. (I've got some sympathy for this.)

[basti313]

https://www.motorsport-magazin.com/form ... er-jubeln/

Sounds good. A measurement when hot is a fair solution, as this is the only number that is relevant for the efficiency/power. Like this any expansion tricks are useless.
Still if the numbers in this article are true, there will be a big advantage for Merc through this season. With the issue for them, that they need to dial back on CR middle of this season.

I mean Mercedes still said they're confident with the engines passing the test regardless, so the others manufactuers can try whatever circumstance against Mercedes, it'll still be the same result.

Well, that might be totally true. Maybe the Merc is really keeping 16:1 all the time in the latest revision. Would be genius. Well earned advantage this season.
Again: If the article is true (IF), others have only 15:1 when hot and need to develop a similar trick. This would be super expensive. So I think leveling this for next season is fine by measuring hot. Still enough work for the others to get the engine to these 16:1 when hot.

[gearboxtrouble]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

[AR3-GP]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

If a car has 0.1mm to much skid wear it’s DSQ. If a car is 1kg underweight it’s DSQ. 5hp is significant. If it wasn’t, Mercedes wouldn’t have done it.

[upsidedowntoast]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

The real deficit is probably a little greater if everyone else goes down to 15.1-15.2 at real operating temperature while Mercedes can maintain that 16, maybe 16.3, but that will still be in the range of 5-10hp.

Which doesn't seem like a lot but it might be meaningful if these cars are going to be energy starved.

My personal opinion is if you're going to implement a hot test you need to keep the ambient test. It's one thing if you explicitly ban a specific engineering element like the Brabham vacuum fan thing, but it's another to basically permit every single other team to have an illegal engine so they can eliminate the advantage of one team (I say "illegal" using the same definition of illegal that everyone against the Mercedes engine uses, which is that it went over 16:1 at any point during the race weekend).

If you eliminate the ambient test but keep the hot test, that's like saying "we have a new procedure to test for flexing wings but we'll eliminate the existing procedure for testing flexing floors".

[Farnborough]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

If a car has 0.1mm to much skid wear it’s DSQ. If a car is 1kg underweight it’s DSQ. 5hp is significant. If it wasn’t, Mercedes wouldn’t have done it.

Those two aren't comparable example to compression defined by geometry, and don't have any bearing.

Both are starting from the specific point the team set at start of race, with expected reduction the norm by the end of race. They have a built in tolerance (weight by the team starting at a point that then doesn't transcend ultimate limit) and skid that is going to wear as acceptable practice with allowance made by the rules for the amount that should still be in place.

The geometric CR is, by the rules stated at "Ambient" to qualify it. Having a hard line without any tolerance is what's wrong here. It looks to me that Mercedes did comply, and logically within accepted long term engineering practice.

I don't think any comment on this forum has picked up on engineering practice in manufacture, and just why the ambient requirement IS logical. Tight tolerance engineering production is usually quantified through an inspection department that would be temperature controlled (often around 68f as near ambient) the subsequent assembly, test, evaluation, durability etc is then tested in dyno and endurance running.
If there's a failure in material performance, the original ambient measuring etc are altered to reflect this. Its nothing unusual to have measured status logically existing at notional ambient. Thats not a conspiracy.

Why it wasn't in rules (apparently) or the timing of placing this there, is open to question. But logically speaking, its just part of fine tolerance in engineering production.

[Badger]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

The real deficit is probably a little greater if everyone else goes down to 15.1-15.2 at real operating temperature while Mercedes can maintain that 16, maybe 16.3, but that will still be in the range of 5-10hp.

Which doesn't seem like a lot but it might be meaningful if these cars are going to be energy starved.

My personal opinion is if you're going to implement a hot test you need to keep the ambient test. It's one thing if you explicitly ban a specific engineering element like the Brabham vacuum fan thing, but it's another to basically permit every single other team to have an illegal engine so they can eliminate the advantage of one team (I say "illegal" using the same definition of illegal that everyone against the Mercedes engine uses, which is that it went over 16:1 at any point during the race weekend).

If you eliminate the ambient test but keep the hot test, that's like saying "we have a new procedure to test for flexing wings but we'll eliminate the existing procedure for testing flexing floors".

No guarantee others go down to 15,2. RBPT was rumoured to use the same exploit "to a lesser degree", that may well put them right under 16 at temperature. Ferrari is rumoured to have changed to a steel head, that would expand less at temperature and maintain the CR more.

[gearboxtrouble]

The 18:1 always sounded lake some lazy journalism that just assumed the worst case of getting it back to last season's mark, never mind that the benefits of going that far with these new fuels might not be there. The 16.1 - 16.3 range is more realistic and wont need clearly illegal defeat devices like secondary chambers. This also makes it a far less significant thing - we're talking about a <5 hp advantage on compression alone which can easily be lost in the noise of all the other dimensions of engine performance.

The real deficit is probably a little greater if everyone else goes down to 15.1-15.2 at real operating temperature while Mercedes can maintain that 16, maybe 16.3, but that will still be in the range of 5-10hp.

Which doesn't seem like a lot but it might be meaningful if these cars are going to be energy starved.

My personal opinion is if you're going to implement a hot test you need to keep the ambient test. It's one thing if you explicitly ban a specific engineering element like the Brabham vacuum fan thing, but it's another to basically permit every single other team to have an illegal engine so they can eliminate the advantage of one team (I say "illegal" using the same definition of illegal that everyone against the Mercedes engine uses, which is that it went over 16:1 at any point during the race weekend).

If you eliminate the ambient test but keep the hot test, that's like saying "we have a new procedure to test for flexing wings but we'll eliminate the existing procedure for testing flexing floors".

No guarantee others go down to 15,2. RBPT was rumoured to use the same exploit "to a lesser degree", that may well put them right under 16 at temperature. Ferrari is rumoured to have changed to a steel head, that would expand less at temperature and maintain the CR more.

The "others go down to 15" take sounds like more lazy journalism that assumes a worst case outcome where other teams do nothing to mitigate a very well known phenomenon that everyone has been addressing for years. My realistic guess is Mercedes exceed 16 and get to the 16.1-16.3 range at operating temp, Red Bull probably do something that keeps them around 16 and the rest maybe see small losses by 0.1-0.4 pts. Low single digit hp differences at most in this one area. Not nothing but its nowhere near the hysterics over 20-40 hp advantage that Mercedes were said to have. If their engine is indeed >16 when hot it is illegal and needs to be changed to top out at 16 but this isn't some magic trick that will single handedly create a 2014 type situation as the media would have you believe.

[upsidedowntoast]

The real deficit is probably a little greater if everyone else goes down to 15.1-15.2 at real operating temperature while Mercedes can maintain that 16, maybe 16.3, but that will still be in the range of 5-10hp.

Which doesn't seem like a lot but it might be meaningful if these cars are going to be energy starved.

My personal opinion is if you're going to implement a hot test you need to keep the ambient test. It's one thing if you explicitly ban a specific engineering element like the Brabham vacuum fan thing, but it's another to basically permit every single other team to have an illegal engine so they can eliminate the advantage of one team (I say "illegal" using the same definition of illegal that everyone against the Mercedes engine uses, which is that it went over 16:1 at any point during the race weekend).

If you eliminate the ambient test but keep the hot test, that's like saying "we have a new procedure to test for flexing wings but we'll eliminate the existing procedure for testing flexing floors".

No guarantee others go down to 15,2. RBPT was rumoured to use the same exploit "to a lesser degree", that may well put them right under 16 at temperature. Ferrari is rumoured to have changed to a steel head, that would expand less at temperature and maintain the CR more.

The "others go down to 15" take sounds like more lazy journalism that assumes a worst case outcome where other teams do nothing to mitigate a very well known phenomenon that everyone has been addressing for years. My realistic guess is Mercedes exceed 16 and get to the 16.1-16.3 range at operating temp, Red Bull probably do something that keeps them around 16 and the rest maybe see small losses by 0.1-0.4 pts. Low single digit hp differences at most in this one area. Not nothing but its nowhere near the hysterics over 20-40 hp advantage that Mercedes were said to have. If their engine is indeed >16 when hot it is illegal and needs to be changed to top out at 16 but this isn't some magic trick that will single handedly create a 2014 type situation as the media would have you believe.

Yeah, the longer this goes on the more overblown it seems to be.

It's still confusing to me that people are reporting the part about teams choosing to veto the original proposal because it includes an ambient test and trying to eliminate the ambient test for 2027. Not sure if that's actually true or if they're just trying to get clicks though. Guess we'll find out after the 28th.

On one hand you have Wolff claiming the difference is only 2-3 hp, and then there's Max claiming it's 20-30. The public seems more inclined to believe Max because he has a reputation for blunt honesty compared to Wolff, but from a pure technical perspective I'm more inclined to believe the conservative estimates.

[dans79]

I don't think any comment on this forum has picked up on engineering practice in manufacture, and just why the ambient requirement IS logical. Tight tolerance engineering production is usually quantified through an inspection department that would be temperature controlled (often around 68f as near ambient) the subsequent assembly, test, evaluation, durability etc is then tested in dyno and endurance running.
If there's a failure in material performance, the original ambient measuring etc are altered to reflect this. Its nothing unusual to have measured status logically existing at notional ambient. Thats not a conspiracy.

Why it wasn't in rules (apparently) or the timing of placing this there, is open to question. But logically speaking, its just part of fine tolerance in engineering production.

Yep the ISO standard is 20 °C ± 0.5 °C. IN most high end work the part to be measured will be taken into the metrology lab and allowed to come to equilibrium before it is measured.

In a lot of instances when you are having things produced to tight tolerances companies just know what the temp is, because it's a standard.

[AR3-GP]

It's over. Regulations have been amended and published late yesterday. The language now makes explicit that ANY technique designed to increase the compression ratio above 16:1 in operating conditions is PROHIBITED. Thermal expansion, 2nd chambers, genie in a bottle, all Prohibited. That ends any possibility for Mercedes to work above the compression ratio limit.

[AR3-GP]

This shouldn't be a surprise to anyone.

2 weeks ago Toto Wolff confessed and said his team will be affected: https://www.skysports.com/f1/news/12433 ... new-season

2 weeks ago Nicolas Tombazi clarified that they don't want anyone getting cute and 16:1 was there to help the new manufacturers and they don't want anyone to work around it: Compression Ratio, DRS Removal and More - 2026 F1 Regulations: You Asked, We Answered

I posted all of this back then and had to entertain a lot of silly arguments about how clear english wasn't really that clear.

[WardenOfTheNorth]

For what it's worth, I hated the Mercedes 2014-2021 years because they were so boring,

2021 boring???

That was one of the most exciting seasons in a long time!!!

[Badger]

But I thought the manufacturers were going to vote down their own proposal? Mark Hughes and several posters here told us so despite the fact that it made no logical sense.

This means that they will have to comply from round 8, in other words if (and it's a big if) this compression ratio thing really does give them a decisive advantage, 7 rounds would likely not be enough to guarantee them any outcome in the championship. I can only speculate on why they moved the change forward two months. Perhaps political pressure stemming from a fear of a boring year, or more likely IMO, Merc doesn't have to make very large changes to comply because they were never running very far above 16:1 to begin with. Round 8 should be right on schedule for their second PU barring any reliability woes.

[catent]

Out of curiosity, and ideally without getting too far off topic:

What was Mercedes power advantage estimated to be in 2014 (and any subsequent seasons), objectively defined in HP? 15? 20? Greater than that?

Just curious if there is any way to roughly predict what a 5, maybe 10 HP advantage would manifest as in terms of relative pace during the 2026 season.

As others have rightfully pointed out, this is a different formula, new engines, and cars that (at least now, absent a change in the 50/50 distribution of ICE/electrical power) will be energy starved at times. Presumably that could exacerbate a relative HP difference in PUs, given that more ICE power = more electrical regen (generally speaking)?

But that could be an overly basic interpretation that misses other key considerations. Perhaps there are other critical elements to power generation and recovery that will be equally or more critical than a handful of HP coming via slightly higher compression ratio in the ICE.