2026 Drama: Alleged engine loophole

[Arcanum]

Given how little factual information there is, it's amazing to see people convict and sentence Mercedes.

How people have decided they are achieving an 18:1 compression ratio? Nothing out there says they are, just that they are above 16:1.

All engine manufacturers will exceed 16:1 in hot running at high RPM's, that's just the nature of engines. Maybe Mercedes have taken some of the elasticity that is intrinsic to a hot engine running at high RPM's and leant into that, maybe they haven't. If they have, the parallel to flexiwings is strong, since Mercedes are taking a property that everyone knows is inevitable, and extending it. Which is quite different from Ferrari intentionally finding a way to trick a fuel sensor.

What's also interesting to note is that Mercedes are the only competitor to have lost a World Drivers Championship due to F1 not following their own rules. And they choose not to take the FIA to court. So the insinuation that Mercedes somehow gets preferential treatment from the FIA has a very large existence proof of that not being true!

[vorticism]

No one knows what the running compression ratios of these engines are. No one knows the compression ratio of the Mercedes engine is.

An engine can be designed to achieve 16:1 during normal operation. Rod stretch and TE can be, obviously, factored into the design, among dozens of other necessary factors, such that the running engine is operating below that value--or above it.

No one knows what the FIA's definition of "geometric compression ratio" is. No one knows what the FIA's test entails. Is the test similar to how they tested the previous 18:1 ratio? Presumably. Did those previous engines have narrowly-connected small sub-chambers? Yes. Do these new ones have narrowly-connected sub-chambers? If TJI has been maintained: yes. Might they also have additional narrowly-connected sub-chambers? Of course.

Do we have any evidence for any of this? No. Can we still speculate rationally about it? Of course.

Does Ferrari's exhaust plate violate the spirit of the rules? You could say that. Is it illegal? No.

[Badger]

Temp for the new test is 130 degrees C. To be voted on.

[FNTC]

Sky F1 reporting an FIA statement on the compression ratio issue. From August 1st need to pass ambient but also at operating temp of 130C.
Also saying they will vote on this in the next ten days.

The Race too:
https://www.the-race.com/formula-1/f1-e ... le-change/

[Tiny73]

Sky F1 reporting an FIA statement on the compression ratio issue. From August 1st need to pass ambient but also at operating temp of 130C.
Also saying they will vote on this in the next ten days.

Surely a vote against by any team is a tacit admission of not fulfilling the requirements? (And thus “illegal” given that cars must comply at all times)?

[motobaleno]

Does Ferrari's exhaust plate violate the spirit of the rules? You could say that. Is it illegal? No.

why??? there is not a rule saying that you cannot use exaust gas to blown diffuser...there is no "spirit" here. simply FIA has ruled progressively in geometric prescriptions in a sense that is becoming more and more difficult to use exaust gas in this sense but if you succeed in doing this, you are not violating any "spirit".
Here we have not to confuse "spirit" in the sense that FIA tends implicitly to pursue some objectives with the regulation (and this is "tendency" not real "spirit"), with spirit when there is an explicit rule saying "your CR is 16 or your max fuel flow must be 100kg/hr and this must be valid in all conditions" and then you find a way to circumvent this prescription formally respecting the enforcing tests...these two cases are substantially different

[MattLightBlue]

Sky F1 reporting an FIA statement on the compression ratio issue. From August 1st need to pass ambient but also at operating temp of 130C.
Also saying they will vote on this in the next ten days.

Surely a vote against by any team is a tacit admission of not fulfilling the requirements? (And thus “illegal” given that cars must comply at all times)?

130 C is surely not enough to make the pre-chamber expand and close a gap. For the aluminum walls it could be. I have the feeling someone at FIA doesn’t want to revert on previous feedback given to Mercedes.

[motobaleno]

Sky F1 reporting an FIA statement on the compression ratio issue. From August 1st need to pass ambient but also at operating temp of 130C.
Also saying they will vote on this in the next ten days.

Surely a vote against by any team is a tacit admission of not fulfilling the requirements? (And thus “illegal” given that cars must comply at all times)?

130 C is surely not enough to make the pre-chamber expand and close a gap. For the aluminum walls it could be. I have the feeling someone at FIA doesn’t want to revert on previous feedback given to Mercedes.

IF there is a pre-chamber it will not close physically by thermal expansion. I'm pretty sure of this. so no static test will work for this. no matter the temperature.

[f1isgood]

"Over recent weeks and months, the FIA and the Power Unit Manufacturers have collaboratively developed a methodology to quantify how the compression ratio changes from ambient to operating conditions. Following validation of this approach, a proposal has been submitted whereby, from 1 August 2026, compliance with the compression ratio limit must be demonstrated not only at ambient conditions, but also at a representative operating temperature of 130°C.

The vote has been submitted to the Power Unit Manufacturers, and its outcome is expected within the next 10 days and will be communicated in due course. As with all Formula 1 regulatory changes, any amendment remains subject to final approval by the FIA World Motor Sport Council."

https://www.fia.com/news/fia-statement- ... -committee

[vorticism]

Does Ferrari's exhaust plate violate the spirit of the rules? You could say that. Is it illegal? No.

why??? there is not a rule saying that you cannot use exaust gas to blown diffuser...there is no "spirit" here. simply FIA has ruled progressively in geometric prescriptions in a sense that is becoming more and more difficult to use exaust gas in this sense but if you succeed in doing this, you are not violating any "spirit".
Here we have not to confuse "spirit" in the sense that FIA tends implicitly to pursue some objectives with the regulation (and this is "tendency" not real "spirit"), with spirit when there is an explicit rule saying "your CR is 16 or your max fuel flow must be 100kg/hr and this must be valid in all conditions" and then you find a way to circumvent this prescription formally respecting the enforcing tests...these two cases are substantially different

Using the engine exhaust for (certain types of) aerodynamic benefit was considered by some to be a violation of the spirit of the rules when RBR did it in 2010 and 2011, hence the 2012 rules change and the development of the Coanda exhausts.

[chrisc90]

So basically illegal engines for 5 months?

[bauc]

Its official (subject to a vote in 10 days), compression ratio bill be measured on 130c temp along with ambient from Aug 1st 2026.

[LM10]

FIA giving Mercedes enough time with their illegal engine. Why wait until August to change the measurement procedure if you’re planning to do it anyway?

13 races to build a gap and walk away in the title race.

But I’m not surprised even in the slightest.

[f1isgood]

The FIA folds, as always. Would be funny if the PU manufacturers disagree and vote differently however. This is embarrassing.

[bauc]

FIA giving Mercedes enough time with their illegal engine. Why wait until August to change the measurement procedure if you’re planning to do it anyway?

13 races to build a gap and walk away in the title race.

But I’m not surprised even in the slightest.

Maybe because FIA initially declared the engine LEGAL? Meaning they are partially to blame?