2026 Drama: Alleged engine loophole

[Ferry]

I find it odd that people are seemingly fine when there is a superior car due to aero, but not a superior car due to the engine.

I agree, and have been thinking the same. I personally find engines much more interesting than aero. It's something most people can understand to a certain degree. We all use them, and have opinions about them.From RC-cars, to motorcycles, to our childhood dreams of turbo charged Porsches, Ferrari V10s, BMW M3s, american muscle cars etc. As a young kid I had a Sachs moped engine which was disassembled and assembled a hundred times. Unlike Adrian Newey, I can't see air. Aero is not easily understandable. Speculating here, but I think for each aero enthusiast there are 10 engine enthusiasts. People care about horse power numbers, accelleration and speed.

I'd rather have spec aero than spec engines. F1 is the pinnacle of motorsport. Such a shame they ditched the MGU-H. If necessary it could've been a spec part. And the irony when you now can buy a new Porsche with a "not road relevant" MGU-H.

[catent]

I have no issue with engine superiority that is grounded in good engineering design, rather than circumvention of an explicitly listed, objectively defined limit in the regulations.

The 16:1 CR limit was implemented in order to make the entry process less expensive/demanding for the likes of Audi and Honda. It exists for clear reasons, and anyone exceeding that defined limit will see relatively increased PU performance.

There are other ways to alter PU performance without exceeding the 16:1 CR limit (like the design of the turbo, for instance).

Or, take Ferrari's flexible floor in 2022; that was dominance via an aerodynamic engineering solution, yet their competitors and the FIA still intervened to eliminate that advantage which was derived via clever aerodynamic design.

[bluechris]

I have no issue with engine superiority that is grounded in good engineering design, rather than circumvention of an explicitly listed, objectively defined limit in the regulations.

The 16:1 CR limit was implemented in order to make the entry process less expensive/demanding for the likes of Audi and Honda. It exists for clear reasons, and anyone exceeding that defined limit will see relatively increased PU performance.

There are other ways to alter PU performance without exceeding the 16:1 CR limit (like the design of the turbo, for instance).

Or, take Ferrari's flexible floor in 2022; that was dominance via an aerodynamic engineering solution, yet their competitors and the FIA still intervened to eliminate that advantage which was derived via clever aerodynamic design.

And yet we still discussing it and we all know that this will pass for 2026 as always for a specific brand.

[Ferry]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

[AR3-GP]

Isn't this just another case of spirit of the rules?

No. You're either pregnant or you're not.

[Rodak]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

The last rules I read had each team propose a c.r test method; I haven't seem any of the methods published. When I was building engines we used the oil method - was just thinking one could also make a cast of the cylinder and head space with some rubber compound (or something) then weigh the casting to determine volume, or have it displace a liquid and measure the displaced volume.

[Arcanum]

And yet we still discussing it and we all know that this will pass for 2026 as always for a specific brand.

Judging from what we hear, I suspect Merc get slightly better treatment because they engage with the FIA.

Ferrari's trick with the fuel sensor required an FIA investigation. Ferrari never went to the FIA and told them what they were doing in advance. Similarly, various tightening of the rules around plank skid blocks and the bib that some teams were using a few years back. In contrast, Merc engaged with the FIA on DAS which is why they got a years use out of it before the ban. Perhaps this is why Mercedes seem to get better treatment, as they don't do things in secret, but engage the FIA enough that they get some leeway?

It appears Merc has, to some extent, engaged with the FIA on the compression ratio topic. At least enough to update the testing rule in October. We don't know how much audit trail there is between the FIA and Mercedes on the CR subject. There could be loads, which would make it quite hard for the FIA to immediately ban it. While Mercedes have said they won't take matters to court, would McLaren, Alpine and Williams be so forgiving if they suddenly ended up with an uncompetitive engine after, potentially, some form of agreement with the FIA that the engine is legal? They are all businesses with sponsor commitments so not being able to race, or being totally uncompetitive, would be a huge impact.

As mentioned already on the thread, the FIA aren't great at being consistent on rules. They weren't going to tighten up on flexiwings until the 2026 regulations, then suddenly they changed their view at the beginning of 2025. Even then they gave the teams nearly 6-months before the new tests were introduced. And that's a front wing which teams evolve during the year anyway.

In Mercedes case, they will already have built multiple race and spare engines across four teams. It''s not like they can just construct something new in two weeks before homologation, or three weeks before the first race. It would be simply impossible to build new components for 16 or so engines in this time.

People might not like this, but I don't see Mercedes engines being banned and unless what they are doing is somehow reversible (unlikely) they cannot make their engines legal in only three weeks. If Merc got clarification from the FIA, and perhaps even had some dialogue around what they were intending to build that resulted in the October test language being updated, it will be hard for the FIA to suddenly change their position and ban them.

Again, people might not like this, but it's really on the FIA for allowing the test language to be set to ambient in October. The implications of doing so are obvious. Which therefore makes it hard for the FIA to ban Mercedes suddenly.

My bet would be on a 2027 rule change. Let's face it, if the total mess of racing we're likely to see transpires, there will be plenty of rule changes into 2027 anyway.

[AR3-GP]

Again, people might not like this, but it's really on the FIA for allowing the test language to be set to ambient in October. The implications of doing so are obvious. Which therefore makes it hard for the FIA to ban Mercedes suddenly.

Mercedes would have an engine spec from September that complied with the regulations before the October amendment. So they can just use that right?

or did they collude with the FIA and keep this detail secret for years...otherwise how would Mercedes have gotten the drop on the other manufacturers? There is something very insidious about it all.

[Hoffman900]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

If the engines measure at 16:1 at ambient, which I suspect all do, then none are legal at 12,000rpm in a firing engine.

[AR3-GP]

If the engines measure at 16:1 at ambient, which I suspect all do, then none are legal at 12,000rpm in a firing engine.

We don't know that. While the rods may stretch at 12,000 RPM, if the head expands then it may compensate for the rod stretch. If one intended to remain under 16:1 at all times, that is what you would do.

[bluechris]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

If the engines measure at 16:1 at ambient, which I suspect all do, then none are legal at 12,000rpm in a firing engine.

Maybe not, we see the smoke so there must be fire somewhere. If that was the case then why all the teams except MB are on the fence and want other measurements in hot conditions if this will make them all out of spec?

[AR3-GP]

Maybe not, we see the smoke so there must be fire somewhere. If that was the case then why all the teams except MB are on the fence and want other measurements in hot conditions if this will make them all out of spec?

Agree

[gearboxtrouble]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

I think natural thermal expansion should be treated differently to a defeat device that only exists to make an engine pass the test. If you rely on stretch and expansion to increase the CR, your engine is legal in both spirit and letter because you pass the test without any caveats. If you use a thermally isolated volume to cheat the test without which your engine would be illegal at ambient temperature then your engine is illegal. My guess is the new test being pushed is intended to show Mercedes running a CR above what could be explained via thermal expansion alone. The intention would be to get the FIA to explicitly ban devices without which an engine would exceed a 16CR at ambient temp for 27 and to penalize any illegal engines via a fuel flow or electrical nerf to allow them to run in 26.

[AR3-GP]

I think natural thermal expansion should be treated differently to a defeat device that only exists to make an engine pass the test. If you rely on stretch and expansion to increase the CR, your engine is legal in both spirit and letter because you pass the test without any caveats. If you use a thermally isolated volume to cheat the test without which your engine would be illegal at ambient temperature then your engine is illegal.

There is precedent for such distinctions. There was a technical directive in summer of 2023 that introduced tighter front wing load test, but also gave FIA authority to deem any competitor wing design in breech, even if they passed the load test! The criteria for it was inferred design intent. When a wing had joints or unusual materials in specific places, FIA would determine by inference that the wing was in breech of the regulations, even if it passed the test. That's why Aston Martin had to change their front wing ahead of the Spanish GP that year and this change killed their entire season.

For reference:

Article 3.2.2 of F1’s technical regulations states that, aside from the driver-operated Drag Reduction System, “all aerodynamic components or bodywork influencing the car’s aerodynamic performance must be rigidly secured and immobile with respect to their frame of reference” and that “these components must produce a uniform, solid, hard, continuous, impervious surface under all circumstances.”

Goss explained how the FIA has revised the methods it uses to ensure teams’ wings comply with the regulations.

“We have a range of load deflection tests that define how much elements can bend and we’ve evolved those tests to represent what the teams are trying to achieve on track and to put a sensible limit on them,” he explained.

“Regardless of conformity with the load tests defined in Article 3.15 [the FIA] would consider any design which uses the relative motion between adjacent components of mechanisms in order to maximise aerodynamic deformation to be in breach of Article 3.2.2,” he added.

Goss gave an example of a design forbidden by the new clarification: “The joint of a rear beam wing and an end plate [that] is decoupled in any way such that it rotates about a pivot there, or that can move laterally or up and down.”

https://www.racefans.net/2023/09/13/new ... y-one-car/


The same thing applies here. The FIA should have the authority to deem certain engine designs in breach of the compression ratio limit regardless of whether or not they pass the existing test because design intent can and should be inferred from the technical drawings of the engine. If there is a 2nd chamber, ban it. If the connecting rods are made from laffy taffy, ban it.

[Hoffman900]

Isn't this just another case of spirit of the rules? All the engines fulfill 16:1 GCR. At least at ambient temperature. What happens during running the engine, who knows? Possibly none of the engines are below 16:1 @ 12000 RPM and elevated temperatures. Thermal expansion and mechanical stretch is unavoidable. Similar to infinite stiff aero parts, which is also impossible. So there comes the old argument back, the test defines the rule. You pass the test, you're good. Don't think I have yet seen how GCR is tested, or have I missed that? It would be easy to get out of the CAD model.

If the engines measure at 16:1 at ambient, which I suspect all do, then none are legal at 12,000rpm in a firing engine.

Maybe not, we see the smoke so there must be fire somewhere. If that was the case then why all the teams except MB are on the fence and want other measurements in hot conditions if this will make them all out of spec?

I’ve explained like a dozen times here already why what I said is true.