2026 Drama: Alleged engine loophole

[Martin Keene]

Ish, do we know appendix in the sporting and technical regs said about how that ratio would be determined, I have not seen that

It's been posted in every other page in this thread I think. But a reminder never hurts

https://api.fia.com/system/files/docume ... -10-16.pdf

"C5.4.3 - No cylinder of the engine may have a geometric compression ratio higher than 16.0. The procedure which will be used to determine this value may be found in the document FIA-F1-DOC-C042 and executed at ambient temperature."

That is the latest version of the rule, the original said:

24 June 2024 version:

"No cylinder of the engine may have a geometric compression ratio higher than 16.0. The procedure which will be used to determine this value may be found in the Appendix to the Technical and Sporting Regulations."

The December 2025 update then reads:

"No cylinder of the engine may have a geometric compression ratio higher than 16.0. The procedure to measure this value will be detailed by each PU Manufacturer according to the Guidance Document FIA-F1-DOC-C042 and executed at ambient temperature."

I don't believe either the former or later procedures have ever been published.

[koolway]

You asked for the appendix of the technical regulation.... which is exactly the link I posted.

the FIA-F1-DOC-042 is private (not published) and is a guidance document for all PU manufacturer that they must rely upon to implement in a detailed measurements procedure that must then be submitted and validated by FIA Technical Department.

[WardenOfTheNorth]

The talk about sensors, how would a sensor measure the geometric CR at racing temperatures?

[Stu]

The talk about sensors, how would a sensor measure the geometric CR at racing temperatures?

It wouldn’t, but it would measure cylinder pressure.

[Martin Keene]

The talk about sensors, how would a sensor measure the geometric CR at racing temperatures?

It wouldn’t, but it would measure cylinder pressure.

Exactly. Pressure sensors will measure peak cylinder pressure, compression ratio is exactly that, it is a ratio, set by the engine design.

[atanatizante]

What do you think, guys, of the explanation given by the Italian F1 dedicated channel - ChronoGP - which attempted to create a virtual demonstration of the camera trick in the Mercedes engine cylinder?

[chrisc90]

[AR3-GP]

The fact that various Mercedes customers are speaking out suggest it is not as clear cut behind the scenes as Mercedes hoped.

[AR3-GP]

From the press conference in Bahrain (@KemalSengulll)

Wolff just spoke about the current engine discussions: "We have taken all the assurances that everything we do complies with the rules. What we're talking about isn't even a massive performance boost. That's the situation, but in my opinion, all our competitors got a bit offended and lobbied hard with the FIA for a long time."

"This lobbying activity has largely ramped up over the last few months. So secret meetings, secret letters written to the FIA—though in this sport, there's no such thing as secret... That's what brought things to this point."

"There's a governance process. If that governance votes for a change to the engine regulations, you have to accept it. It is what it is. This would be detrimental to all teams powered by Mercedes engines in such a scenario."

"The benefit this would bring us is just a few horsepower."

"We will always respect the sport's governance. If the sport's management makes a decision against or in favor of our position, we have to comply with both."

[Sergej]

What do you think, guys, of the explanation given by the Italian F1 dedicated channel - ChronoGP - which attempted to create a virtual demonstration of the camera trick in the Mercedes engine cylinder?

I don't know if what he's saying makes sense; what I know is that Fabiano Vandone is an absolute clown, I remember when in 2023 after Singapore he went all-in saying that Red Bull used a flexible nose (!) and with TD18 they wouldn't have won anything anymore lot of made up stuff from him.

[venkyhere]

From the press conference in Bahrain (@KemalSengulll)

Wolff just spoke about the current engine discussions: "We have taken all the assurances that everything we do complies with the rules. What we're talking about isn't even a massive performance boost. That's the situation, but in my opinion, all our competitors got a bit offended and lobbied hard with the FIA for a long time."

"This lobbying activity has largely ramped up over the last few months. So secret meetings, secret letters written to the FIA—though in this sport, there's no such thing as secret... That's what brought things to this point."

"There's a governance process. If that governance votes for a change to the engine regulations, you have to accept it. It is what it is. This would be detrimental to all teams powered by Mercedes engines in such a scenario."

"The benefit this would bring us is just a few horsepower."

"We will always respect the sport's governance. If the sport's management makes a decision against or in favor of our position, we have to comply with both."

in other words,
"we are too clever for our own good, and as a result of it, the current engine is illegal"

[Seanspeed]

From the press conference in Bahrain (@KemalSengulll)

Wolff just spoke about the current engine discussions: "We have taken all the assurances that everything we do complies with the rules. What we're talking about isn't even a massive performance boost. That's the situation, but in my opinion, all our competitors got a bit offended and lobbied hard with the FIA for a long time."

"This lobbying activity has largely ramped up over the last few months. So secret meetings, secret letters written to the FIA—though in this sport, there's no such thing as secret... That's what brought things to this point."

"There's a governance process. If that governance votes for a change to the engine regulations, you have to accept it. It is what it is. This would be detrimental to all teams powered by Mercedes engines in such a scenario."

"The benefit this would bring us is just a few horsepower."

"We will always respect the sport's governance. If the sport's management makes a decision against or in favor of our position, we have to comply with both."

They wouldn't all be making this fuss over a few HP, including Merc and their customers and others trying to get rid of the advantage.

[AR3-GP]

From the press conference in Bahrain (@KemalSengulll)

Wolff just spoke about the current engine discussions: "We have taken all the assurances that everything we do complies with the rules. What we're talking about isn't even a massive performance boost. That's the situation, but in my opinion, all our competitors got a bit offended and lobbied hard with the FIA for a long time."

"This lobbying activity has largely ramped up over the last few months. So secret meetings, secret letters written to the FIA—though in this sport, there's no such thing as secret... That's what brought things to this point."

"There's a governance process. If that governance votes for a change to the engine regulations, you have to accept it. It is what it is. This would be detrimental to all teams powered by Mercedes engines in such a scenario."

"The benefit this would bring us is just a few horsepower."

"We will always respect the sport's governance. If the sport's management makes a decision against or in favor of our position, we have to comply with both."

in other words,
"we are too clever for our own good, and as a result of it, the current engine is illegal"

He sounds very guilty.

[chrisc90]

8 cars less on the grid in Melbourne

[f1isgood]

I will wait till something concrete comes out of this. This is all nice and good but FIA has to show they can do something about this. Red Bull is a conundrum to me. What if they also fail the new tests? Do they have a backup engine?