I might not remember correctly but the compression ratio has to be according to the rules during the competition, not just during measurement. It’s the same as with the flexi wings, the mcl tyre cooling, DAS so on. It is still against the rules. This cycle the teams have taken the step, because the advantage or the risk of it is unacceptable. So if Mercedes gets away with it, I hope all their engines overheat and blow up each and every race (no driver harm) and they don’t win a race til 2029
There are two compression ratios, for every engine that uses or generates heat as part of its compressive function: - Static compression ratio: the amount a fuel can be compressed in ambient conditions. - Dynamic compression ratio: the amount a fuel can be compressed in the engine's running condition. The regulations in F1 clearly stated that engine compression are measured at ambient conditions. This means it is static compression ratio, not dynamic compression ratio, that is being regulated. "Ambient" means the prevailing weather conditions at a venue at the moment the measurement is taken. We know this partly because the term "ambient" is also used to determine what temperature fuel is allowed to be when stored on competition days. At one point, it could not be stored at less than 10 C below ambient (it is now required to be stored at ambient). If "ambient" meant "running condition", then keeping fuel at 10 C below that would cause it to spontaneously combust every day. Hello pit lane fires… All engines must comply, even if the day is hotter than expected. If there was a race weekend at 62 degrees C this year, the engines would have had to be compliant with the static compression ratio. This applies even if the drivers didn't drive for heatstroke risk - if cars are presented for a session, then the ambient of that moment is the one that is used. The fact it's higher than the teams anticipated is not considered a defence. Even static compression has a loophole. Greater static compression is possible at cold races than hot ones. If something in the engine raises the static compression ratio when the ambient temperature falls, this would allow the engine to run faster at colder races. In practise, this is physically less likely than the proposed ability to increase dynamic compression ratio, because materials expand when heated. Bimetallic strips that turn off kettles when water boils have worked that way for decades - so the issue is actually controlling the increase in dynamic compression ratio at high temperature. Uncontrolled increases are trivial - increases while controlling for unwanted vibrations, power inconsistencies and engine damage are the real trick. The secondary requirements needed to control these side effects of very high dynamic compression is why teams have generally shied away from deliberately employing it. The most likely reason the FIA used wording that locked the definition of "compression ratio" to static rather than dynamic is enforcement. Static compression can be measured by one person with basic measuring equipment, any time the car is in parc fermé and has not been running for about an hour. This is easily arranged at every single race, as well as at initial Thursday scrutineering. (The only reason it doesn't get done every race is because the full regulations are about as thick as a biscuit tin, or maybe a large jewellery box). Dynamic compression ratio is much trickier to enforce. That makes the originally-mooted scenario of "just" taking out Mercedes look wonderful in comparison. There's also the point that the way the regulations are written now, if the rule is changed to mean dynamic compression ratio, there would no longer be anything covering the static compression ratio, leaving a whole new bunch of loopholes for the taking. Also, if the dynamic compression ratio is made 16:1, given no F1 engine's running temperature can possibly be every venue's ambient, and the manufacturers have been building static compression ratios of 16:1, then every single one will fall at Melbourne. Every single one. That's simply physics. Remember, the only thing Mercedes was "getting away with" was following the regulations as written and as reasonable to interpret by anyone who understood what an engine compression ratio was in the first place. The FIA has just told everyone that only telepathy or cheating is allowed - and none of the teams or engine manufacturers has a telepath on the staff.
