Pre-Season Engine drama

[Nitrodaze]

I suspect that *IF* we ever find out that the rumors are true, the metals that expand will be used in very limited areas. As you say, all metals expand with temperature, but for the most important areas this has been factored in so that the engine is at it's best under full operating temperature. As such bores, pistons, rods, valves, bearings would likely not change over how they were designed. Otherwise it would probably result in either increased engine wear or excess friction.

BUT we have areas which could expand slightly with heat and not impact wear or friction in a negative way.

*IF* they do dig in enough to find out if the rumors are true, I'm primarily suspecting various coated surfaces within the actual combustion chamber area and/or the TJI/HCCI prechamber areas, primarily the nozzles. Piston crowns, valve faces, and the various prechamber components could expand without impacting tolerances beyond what is desired to raise compression ratio.

*IF* the rumors have merit, it would take expansion that would decrease the chamber area of each cylinder by a bit less that one cubic centimeter. With a large bore as well as large valves there is a decent bit of surface area to play with, and it might be possible.




It will be interesting to see what comes out of the FIA meeting, but I have a feeling that it might end up like the Ferrari engine saga. Clarifications and changes forced, but nothing ever proven that the public gets to see.

If they have found a loophole, it would most probably be in the design of the conrod. They may have designed the conrod to stretch under temperature to increase the compression from 16:01 to 18:1. The Aluminium block and bore may be the same as from the previous engine. Of course, this is pure speculation; we would never know what trickery they may have used. Whatever it is, it is quite ingenious.

[Steve Boyd]

The swept volume limit is 1600 cc, so 266.7 cc per cylinder.

For a 16:1 compression ratio the combustion volume is therefore 17.78 cc.

For the compression to increase to 18:1 the combustion chamber needs to reduce to 15.69 cc, a reduction of just over 2 cc.

If we take the bore of the engine to be 80 mm (as indicated by the "2014-2025 engine technical specifications" on this page https://en.wikipedia.org/wiki/Formula_One_engines) then expanding the length of the conrod and piston crown height by 0.4 mm would do the trick.

Sounds simple but the crankcase and cylinder head also expand so you've got to get the rod+piston crown height to expand by 0.4 mm more than the expansion of the crankcase+head. The problem here is that aluminium alloys, typically used in crankcases expand by roughly twice as much as the steels typically used in conrods for the same temperature rise. It might actually be easier to use an alloy steel for the crankcase and reduce that expansion rather than try to increase the expansion of the rod+piston.

[Nitrodaze]

The swept volume limit is 1600 cc, so 266.7 cc per cylinder.

For a 16:1 compression ratio the combustion volume is therefore 17.78 cc.

For the compression to increase to 18:1 the combustion chamber needs to reduce to 15.69 cc, a reduction of just over 2 cc.

If we take the bore of the engine to be 80 mm (as indicated by the "2014-2025 engine technical specifications" on this page https://en.wikipedia.org/wiki/Formula_One_engines) then expanding the length of the conrod and piston crown height by 0.4 mm would do the trick.

Sounds simple but the crankcase and cylinder head also expand so you've got to get the rod+piston crown height to expand by 0.4 mm more than the expansion of the crankcase+head. The problem here is that aluminium alloys, typically used in crankcases expand by roughly twice as much as the steels typically used in conrods for the same temperature rise. It might actually be easier to use an alloy steel for the crankcase and reduce that expansion rather than try to increase the expansion of the rod+piston.

I hear Ferrari has gone down the route of a steel crankcase. Even so, they are apparently revising the design of the engine to adopt the Mercedes approach. I think there is more to it than meet the eyes.

[Steve Boyd]

I think there is more to it than meet the eyes.

I think you're right, but will we ever find out the truth?

The other factor is that if you try to do anything fancy with the pistons it has to withstand huge forces and if you don't get that right it's going to ruin your reliability.

It also could be a huge bluff forcing other teams to use part of their cost-cap chasing wild geese.

[airshifter]

I think you're right, but will we ever find out the truth?

The other factor is that if you try to do anything fancy with the pistons it has to withstand huge forces and if you don't get that right it's going to ruin your reliability.

It also could be a huge bluff forcing other teams to use part of their cost-cap chasing wild geese.

I wondered about the bluff angle as well. Get in the other teams heads early in the game!

But IF it's real, I doubt we will ever get the full details. Only time will tell, but if either team builds a strong engine it should help with tissue sales until it's all sorted out.

[Steve Boyd]

In the news thread @Fortitude posted:

Mattia Binotto just told Ferrari why they are already doomed in 2026 battle with Mercedes
21 January 2026
David Comerford
F1 Oversteer

It has been reported that Ferrari could protest the results of the Australian Grand Prix, the first round of the season. They feel Mercedes are breaking the spirit of the rules. However, speaking to The Race, Audi boss Mattia Binotto questioned whether this approach is viable, because they can’t pinpoint exactly which feature of the car is illegal. “You can protest if you know what you’re protesting,” Binotto, the former Ferrari team principal, said.

F1 teams will meet to discuss the issue on Thursday, but Binotto says this won’t lead to a ban. Instead, Audi are pushing for the introduction of a real-time measuring device, but this would take time. “I don’t think there will be clarity or compromise,” he said. “The meeting, which has been set for the 22nd of January, is more to continue to discuss how can we improve or develop a methodology for the future to measure the compression ratios in operating conditions.”

‘Can’t pinpoint exactly which feature of the car is illegal’;

https://www.f1oversteer.com/news/mat...with-mercedes/

The bit that says Audi want real time monitoring of compression ratio is interesting. Compression ratio isn't a pressusre ratio, its a volume ratio. To monitor it in real time at 12000 rpm would need a volume measurement at the bottom of the stroke and another at the top of the stroke 2.5 milliseconds apart. You could monitor cylinder pressure continuously but correlating that with compression ratio is virtually impossible. The rule as written is clear and easily enforcible and in my opinion should be left as it is. As engine parts expand in use the compression ratio is bound to change, and that change will be different for different engine designs. the only way to make it the same for everybody would be to mandate a single engine and then it wouldn't be F1.