AR3-GP wrote: ↑25 Dec 2025, 05:24
vorticism wrote: ↑25 Dec 2025, 05:00
Ah, dang. That’s what I was expecting. Painful. Well, I guess something similar to what I was working on seven years ago is about to enter the public domain...
...
I’ll say this much at this point. It has nothing to do with the geometric compression ratio nor thermal expansion, and it in no way contravenes the regulations, including their previous drafts. The “measured at ambient temperature” addition to the regulations is a red herring and could conceivably make the test more stringent.
It's going to be a two-tier Formula 1 in 2026. The haves, and the have-nots.
I wouldn't quite go that far. Combustion efficiency is important but there are a dozen other parameters that are just as important as in any turbocharged engine. The '26 formula engine formula seems to me to be simpler than the preceding formula. This is a much different situation than the transition from the 2013 engine regulations to the 2014 engine regulations. The ICE component now supplies less of the total system output. I would not be surprised if this feature was already in use in the MGUH-era formulas.
I’ll say again the feature in question is not reliant upon thermal expansion any more than any other component of the ICE is reliant upon thermal expansion, and it does not, and cannot, alter the geometric compression ratio of the cylinder. That’s the brilliant part of it. Just sublime. When people see it the response will be like that of what they had when they saw the split-turbo for the first time: “Oh. ... Well. ... Alright. ...” No complaining, just respect for a brilliant idea. If you didn’t think of it, you didn’t think of it. And that’s all that can be said about it. Sublime. Now, you may need to be of an engineer’s or artisan’s mindset to have that response, but that goes for any of aspect of these cars. Most people would not care about what a split turbo is, nor care much about, say, the intricacies of an RB7.
FDD wrote: ↑26 Dec 2025, 00:58
...we also have G. Anderson statement, clearly saying that piston expanding of 0,3mm needed to achieve 18:1 compression ratio, it's not possible with the materials allowed.
He's right. TE across these sub ~150mm dimensional ranges is too minimal. That's why I had been suggesting discrete components (like the sensor plug) or kinematics (articulated components) to achieve movement of a large enough scale. If it was something as unavoidable as somehow leveraging TE interactions of the conrod, piston, block, or head, then this phenom will be available to all of the teams. It's not any of these things, though.
What's throwing people off, including the press, is the "ambient temperature" change to the wording of the regulations. We outsiders, including journalists, do not know why that wording was changed. It could be for benign reasons f.e. in the case of the FIA wanting to make the testing procedure as easy as possible for themselves, which would include handling parts at room temperature. Too much is being read into the passage. It's a red herring.
Further thoughts:
--We don't know if Ferrari, Audi, and Honda do not themselves also have this innovative feature.
--As it relates to "...no cylinder of the engine may have a geometric compression ratio greater than..." the term "cylinder" is not defined in the regs. Is an engine cylinder the bore in the block, or does it include the cylinder head chamber volume? In common use I've seen such a general term as "cylinder" used in various ways. To describe the volume formed by the bore & piston face beneath the cylinder head, as well as to describe the swept volume, as well as to describe the total volume encapsulated between the cylinder head and the piston face (at any point amid piston travel). If it's bore only, then the cylinder head volume is constrained volumetrically only by the engine displacement specification, which is 1600cc +0/-10.
--People were also getting caught up on the term "compression ratio" (including me). Try calling it the "expansion ratio" instead. How would that change your evaluation of the topic? If these are Miller cycle engines, then we shouldn't conflate the compression ratio values with those of more familiar Otto cycle engines. I.e. 18:1 would be a high compression ratio for an Otto cycle engine, but it would not necessarily be a high compression ratio for Miller cycle engine. Like with "ambient temperature" people are reading too much into "compression ratio," and in this instance drawing a line between two misunderstandings: that this must be about thermal expansion affecting the compression ratio of an Otto cycle engine.
