Pre-Season Engine drama

Rumour has it that Mercedes has built a monster engine, and Redbull have a similar concept. It is looking like a Mercedes Engine dominance is coming. This may be good for McLaren, but I suspect Mercedes may be the team to beat if the rumour is correct.

I am curious to see how the Ford engine in the Redbull hold up to the competition. Car giant Ford have alway built championship-winning F1 engines in the past, but times have changed as Honda found in the early stages of their return to F1.

I wonder if the championship is going to be fought between the Mercedes-powered cars. The Ferrari may have chassis challenges to overcome, but I expect the Ferrari engine to be up there with the Mercedes. The embarrassment that Ferrari has suffered in the 2025 season may drive them to produce a better car that may surprise everyone. They obviously need more than a better car to win championships. The need to carry out a major overhaul of their operation side, l feel.

For those who may not know what is going on. Mercedes has found a loophole that allows them to run their engines at a higher compression ratio (18:1 vs. 16:1). This will ultimately give them approximately 15 HP greater. RB may also be going down this path.

The other engine makers (Ferrari, Honda, and Audi) are asking FIA to intervene before the season and stop it.

If the FIA changes its procedures for evaluating engines, the RB and Mercedes could be crippled. FIA had pushed out a compromise that they will run with the 2026 rules and then change them for 2027. Ferrari is said to have filed a protest.

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Originally Posted by F1nKS

For those who may not know what is going on. Mercedes has found a loophole that allows them to run their engines at a higher compression ratio (18:1 vs. 16:1).

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KaBoom!

I've also seen a rumour that Adrian Newey has found a loophole that gives more downforce than should be expected from the new chassis/floor regulations. We could be in for a repeat of the Brawn double-diffuser protests and appeals as well as an argument over engines.

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Originally Posted by F1nKS

For those who may not know what is going on. Mercedes has found a loophole that allows them to run their engines at a higher compression ratio (18:1 vs. 16:1). This will ultimately give them approximately 15 HP greater. RB may also be going down this path.

The other engine makers (Ferrari, Honda, and Audi) are asking FIA to intervene before the season and stop it.

If the FIA changes its procedures for evaluating engines, the RB and Mercedes could be crippled. FIA had pushed out a compromise that they will run with the 2026 rules and then change them for 2027. Ferrari is said to have filed a protest.

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Well said buddy :-)

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Originally Posted by F1nKS

For those who may not know what is going on. Mercedes has found a loophole that allows them to run their engines at a higher compression ratio (18:1 vs. 16:1). This will ultimately give them approximately 15 HP greater. RB may also be going down this path.

The other engine makers (Ferrari, Honda, and Audi) are asking FIA to intervene before the season and stop it.

If the FIA changes its procedures for evaluating engines, the RB and Mercedes could be crippled. FIA had pushed out a compromise that they will run with the 2026 rules and then change them for 2027. Ferrari is said to have filed a protest.

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Alleged cheating, alleged advantage. At this point it's nothing more than claims really.

And I fully expect this to be less messy in terms proving compression ratio, but just as if not more messy in terms of proving that they knew it would be deemed illegal if found and are by that reasoning cheating. Just like with the Ferrari fuel flow loopholes, it might be simply too hard to prove.

And I suspect that if the FIA clamps down hard on the Article 1.5 basis that "Formula 1 cars must comply with these regulations in their entirety at all times during a competition"..... well the only compression ratio testing during the competition takes place in the pits, at ambient temps. To introduce another test is to change the regs, and I might add that if they decided on a way to heat the engines to near operating temps, the other teams might have higher CRs as well. Intentional or not, if they break 16:1..... but wait, they can't do that because they have already changed the regulation to allow that testing. It's a slippery slope.

I personally think the reduction in compression ratio was done on insane theory already. If Audi or anyone else new doesn't want to invest in figuring that out, they weren't that invested in F1 to begin with, and we shouldn't reduce the potential output to appease them and make it easier.

Hard to say how it will all go down, but the most recent precedent I can think of is DAS. And even though it was known that DAS existed based on a loophole, the FIA let Merc run it for the year, as well as allowed others to develop it if they wanted. But with engine homologation a different beast, the FIA might be in a position to deem it simply legal or not.

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Originally Posted by airshifter

Alleged cheating, alleged advantage. At this point it's nothing more than claims really.

And I fully expect this to be less messy in terms proving compression ratio, but just as if not more messy in terms of proving that they knew it would be deemed illegal if found and are by that reasoning cheating. Just like with the Ferrari fuel flow loopholes, it might be simply too hard to prove.

And I suspect that if the FIA clamps down hard on the Article 1.5 basis that "Formula 1 cars must comply with these regulations in their entirety at all times during a competition"..... well the only compression ratio testing during the competition takes place in the pits, at ambient temps. To introduce another test is to change the regs, and I might add that if they decided on a way to heat the engines to near operating temps, the other teams might have higher CRs as well. Intentional or not, if they break 16:1..... but wait, they can't do that because they have already changed the regulation to allow that testing. It's a slippery slope.

I personally think the reduction in compression ratio was done on insane theory already. If Audi or anyone else new doesn't want to invest in figuring that out, they weren't that invested in F1 to begin with, and we shouldn't reduce the potential output to appease them and make it easier.

Hard to say how it will all go down, but the most recent precedent I can think of is DAS. And even though it was known that DAS existed based on a loophole, the FIA let Merc run it for the year, as well as allowed others to develop it if they wanted. But with engine homologation a different beast, the FIA might be in a position to deem it simply legal or not.

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I think they may have a tough time proving the compression ratio is illegal. Afterall, teams are using very similar alloys for the conrod and piston. And these things would expand under increased temperatures. That said, no one knows what materials Mercedes is using for their engine parts. It would be a sad day if regulations started specifying what materials should be used for all engine components.

I wonder how such an engine would work on the desert race tracks.

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Originally Posted by Steve Boyd

I've also seen a rumour that Adrian Newey has found a loophole that gives more downforce than should be expected from the new chassis/floor regulations. We could be in for a repeat of the Brawn double-diffuser protests and appeals as well as an argument over engines.

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Bring on pre-season testing, l say.

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Originally Posted by Steve Boyd

I've also seen a rumour that Adrian Newey has found a loophole that gives more downforce than should be expected from the new chassis/floor regulations. We could be in for a repeat of the Brawn double-diffuser protests and appeals as well as an argument over engines.

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Well I haven't seen the mention of what Newey might have found, but just forum members on F1Technical have found loopholes in the aero package regs that seem would easily change the idea of outwash being unlikely. I'm sure a guru like Newey has been deep into just about any possibility.

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Originally Posted by Nitrodaze

I think they may have a tough time proving the compression ratio is illegal. Afterall, teams are using very similar alloys for the conrod and piston. And these things would expand under increased temperatures. That said, no one knows what materials Mercedes is using for their engine parts. It would be a sad day if regulations started specifying what materials should be used for all engine components.

I wonder how such an engine would work on the desert race tracks.

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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.

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Originally Posted by airshifter

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.

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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.

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.