2026 Drama: Alleged engine loophole

[ferkan]

Today there was an outbreak of propaganda being posted by Italian media sources for reasons...
AMUS is also useless without Michael Schmidt. None of the sources being parroted are credible. Stop losing your minds over planted bs stories.

I dont think this is the case. Toto went out quite angrily 2 days ago commenting “fix your damn car” and there were reports yesterday of Merc boss saying he would take it to court. If Merc has the trick, its season over and other manufacturers will not let it slide and get embarrassed by someone loopholing their way into dominance if they feel its not by the rule.

[Hoffman900]

This place was a ghost town concerning actual tech discussion, but now that it’s tabloid rumors and politics, it’s pretty active. Just how it goes, I guess.

[bluechris]

This place was a ghost town concerning actual tech discussion, but now that it’s tabloid rumors and politics, it’s pretty active. Just how it goes, I guess.

You are right but we don't have anything to do till the next test, at least we celebrate the new "tech" that MB brings to the table. True or not it's a matter of time to be revealed since the cat exited the bag.

[matteosc]

This is how the "1.0 cc" works. And it is very sneamy. You guys let me know if you see anything illegal:

A cylindrical chamber in the cylinder head open to the combustion chamber has a conical plug inserted though it's central axis. This conical plug is essentially a heat activated valve that leaves a very narrow annulus between the chamber walls and the valve seat. The plug is made of a higher thermal expansion material than the head. It doesn't have to be any fancy alloy. The cylinder head could be steel and the plug aluminum for example. At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test. This gap could be a "leak" of microns wide. The supposed cylinder volume is in it's highest form here.

Then, as the engine heats up, the annular conical plug expands, creating perfect metal to metal seal, and the annulus no longer exists. That "1 cc" is now sealed off from the cylinder volume and higher compression ratio is achieved.


That said, this trick is easy to pull off and will be easily copied by manufacturers if the FIA passes it as legal.

I do see something illegal, since the rule states that the compression ratio must be a maximu of 16:1, with an additional general rule stating that the car needs to be regular at any time during the event.

Then there is the measurement procedure, described in a different point, but it is not the rule itself. As for many other points of the regulation, the measurement procedures can be changed whenever is needed.

This system is designed to comply with the me measurement procedure, but it is designed to go against the rule, since the engine has a compression ratio greater than 16:1. We see this kind of approach all the time, with wing flexibility or even with Ferrari's flowmeter trick. But on a structural part of an engine, whith everything (fuel included) optimize for a 18:1 ratio? Risky thing to do.

[Rodak]

At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test.

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

[Hoffman900]

At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test.

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

This. The reading comprehension here is reprehensible.

As has been pointed out here several times by people, it’s essentially:
CR = (swept volume + clearance volume)/clearance volume

That’s it. Nothing more, nothing less.

As I have pointed out here numerous times, the clearance volume is different than running clearance volume due to thermal expansion and rod stretch. You can’t mimic this in the pits. If you want to be fair, you assume the clearance volume is zero (piston to head clearance). You can’t come any closer than a piston hitting the head.

This change exists in all engines and is a well understood phenomenon. It’s been totally butchered by journalists and content creators who never built engines and fans who have never built engines.

[dialtone]

At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test.

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

This. The reading comprehension here is reprehensible.

As has been pointed out here several times by people, it’s essentially:
CR = (swept volume + clearance volume)/clearance volume

That’s it. Nothing more, nothing less.

As I have pointed out here numerous times, the clearance volume is different than running clearance volume due to thermal expansion and rod stretch. You can’t mimic this in the pits. If you want to be fair, you assume the clearance volume is zero (piston to head clearance). You can’t come any closer than a piston hitting the head.

This change exists in all engines and is a well understood phenomenon. It’s been totally butchered by journalists and content creators who never built engines and fans who have never built engines.

Honestly I don’t understand if you are on purpose not understanding the issue or you are just ignoring it.

And yet despite your self assessed intellectual superiority you persist.

Nothing you said is unknown or hard to understand. I repeat to you once again that Ferrari, Honda and Audi know this as well as you do.

Some teams interpreted the ruling as 16:1 was the most you could reach INCLUDING expansion, stretch and any other phenomenon you want to add. Other teams thought the starting point was 16:1.

Since these teams helped draft the rules and the 16:1 was requested by Audi to simplify their engine design and ease their coming in the sport, they ought to know more than you do about the spirit behind this rule.

Please stop repeating the same thing over and over, we got it, it’s not the issue.

[Hoffman900]

The issue is no one knows there is an actual issue and it’s all just hersay and for most, general ignorance of what compression ratio even is, or how strict interpretation is impossible in reality.

As for why I am repeating myself, 33 pages into this thread and people still can’t differentiate between compression ratio and cranking compression, even though it’s been explained numerous times.

This is mostly large corporate teams playing politics and getting their fans wound up. For content creators, it’s clicks.

[dialtone]

The issue is no one knows there is an actual issue and it’s all just hersay and for most, general ignorance of what compression ratio even is, or how strict interpretation is impossible in reality.

As for why I am repeating myself, 33 pages into this thread and people still can’t differentiate between compression ratio and cranking compression, even though it’s been explained numerous times.

This is mostly large corporate teams playing politics and getting their fans wound up. For content creators, it’s clicks.

A team is threatening to sue the FIA, another 3 now support it.

A fourth one is threatening to sue back if they are stopped.

The issue exists.

[Rodak]

At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test.

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

This. The reading comprehension here is reprehensible.

As has been pointed out here several times by people, it’s essentially:
CR = (swept volume + clearance volume)/clearance volume

That’s it. Nothing more, nothing less.

As I have pointed out here numerous times, the clearance volume is different than running clearance volume due to thermal expansion and rod stretch. You can’t mimic this in the pits. If you want to be fair, you assume the clearance volume is zero (piston to head clearance). You can’t come any closer than a piston hitting the head.

This change exists in all engines and is a well understood phenomenon. It’s been totally butchered by journalists and content creators who never built engines and fans who have never built engines.

Oddly enough, that's exactly what I said so I do not know what you are going on about. I think there's a reading comprehension issue here. I was pointing out that compression ratio was not measured with a compression gauge. Clear enough? I would also point out that a piston does not have to have a flat upper surface, so any volume in the piston itself whether ± must also be accounted for.

Edited to add: I think I misunderstood you comment and actually you agree with my post. If so, I apologize and stand corrected. Sorry.

[syndicate1]

Apologies in advance if this should be in a different thread.

Re: Mercedes engines and their claimed 18:1 compression at operating temperature. Are the teams (McLaren, Williams, and Alpine) that use Mercedes engines benefitting as well?

[PlatinumZealot]

At room temperature the annulus is open. Only a tiny gap in the annulus is needed for air to pass through during the compression test.

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

Swept volume alone cannot measure compression ratio. You have to include the final compressed volume.

[PlatinumZealot]

Except that the compression ratio is not measured with a compression tester, it is a measurement of the swept volume as the piston moves up and down compared to the un-swept volume when the piston is fully up. As has been stated here so many times it's getting old, it is the 'geometric' ratio. One measures the total cylinder volume when the piston is down then the total volume when the piston is up and divides one by the other.

This. The reading comprehension here is reprehensible.

As has been pointed out here several times by people, it’s essentially:
CR = (swept volume + clearance volume)/clearance volume

That’s it. Nothing more, nothing less.

As I have pointed out here numerous times, the clearance volume is different than running clearance volume due to thermal expansion and rod stretch. You can’t mimic this in the pits. If you want to be fair, you assume the clearance volume is zero (piston to head clearance). You can’t come any closer than a piston hitting the head.

This change exists in all engines and is a well understood phenomenon. It’s been totally butchered by journalists and content creators who never built engines and fans who have never built engines.

Honestly I don’t understand if you are on purpose not understanding the issue or you are just ignoring it.

And yet despite your self assessed intellectual superiority you persist.

Nothing you said is unknown or hard to understand. I repeat to you once again that Ferrari, Honda and Audi know this as well as you do.

Some teams interpreted the ruling as 16:1 was the most you could reach INCLUDING expansion, stretch and any other phenomenon you want to add. Other teams thought the starting point was 16:1.

Since these teams helped draft the rules and the 16:1 was requested by Audi to simplify their engine design and ease their coming in the sport, they ought to know more than you do about the spirit behind this rule.

Please stop repeating the same thing over and over, we got it, it’s not the issue.

I agree with Hoffman.

Compression ratio is literally a given and understood thing and cannot be changed. The teams know what is measured.

The teams are not arguing over any semantics. They literally saying that Mercedes have done a trick to intentially reduce the compressed volume of the cylinder smaller than 1/16 of the maximum geometric volume. Expansion stretch etc doesn't matter, the compression ratio equation still stands. Engines are measured under standard conditions. All teams know this. The inevitable incidental expansions are expected. The teams are arguing that Mercedes has done a trick that intentially goes past any incidental thermal effect.

[venkyhere]

Atleast in this forum, the Question has now boiled down to one of the following interpretations:

A) 16:1 limit is only meant for the measurement test at ambient
OR
B) 16:1 limit is only meant for the measurement test at static engine temp (heating the whole block up without engine running)
OR
C) 16:1 limit is ABSOLUTE, to be maintained at ALL operating temps, just that FIA will measure it in conditions described in A or B

If it is (C) what will be the number that they are going to 'measure' and say 'yes, this engine is fine' , is it going to 16:1 itself or something like 15.9 : 1 / 16.1 : 1 ? (because static heating is not going to mimic the heat distribution during actual operation.

Can anyone detail the 'actual method' used by FIA to determine this ? is the traditional 'liquid/oil' displacement measurement based ? or some other fancy method ?
4 engine manufacturers have their own understanding (whichever out of A/B/C) and Mercedes is the only one who disagrees. How did the 4 of them know that their A/B/C is different from Mercedes' A/B/C ? Did they glean that from the barcelona lap data ?

[Peter Ian Staker]

Atleast in this forum, the Question has now boiled down to one of the following interpretations:

A) 16:1 limit is only meant for the measurement test at ambient
OR
B) 16:1 limit is only meant for the measurement test at static engine temp (heating the whole block up without engine running)
OR
C) 16:1 limit is ABSOLUTE, to be maintained at ALL operating temps, just that FIA will measure it in conditions described in A or B

If it is (C) what will be the number that they are going to 'measure' and say 'yes, this engine is fine' , is it going to 16:1 itself or something like 15.9 : 1 / 16.1 : 1 ? (because static heating is not going to mimic the heat distribution during actual operation.

Can anyone detail the 'actual method' used by FIA to determine this ? is the traditional 'liquid/oil' displacement measurement based ? or some other fancy method ?
4 engine manufacturers have their own understanding (whichever out of A/B/C) and Mercedes is the only one who disagrees. How did the 4 of them know that their A/B/C is different from Mercedes' A/B/C ? Did they glean that from the barcelona lap data ?

Arguing about the “real” interpretation of the rule is kinda pointless now because the rule was clearly not prescriptive enough and its final interpretation and likely subsequent amendment will be decided by back room politics.
As for the rest I don’t think we got much of an idea.