Mercedes' rivals have been challenged to put some "skin in the game" and lodge a protest at Formula 1's Australian Grand Prix if they are so unhappy about the situation surrounding compression ratios.
Ahead of what could be an important F1 Commission meeting next week in Bahrain, the controversy surrounding Mercedes having found an engine advantage via compression ratio rule interpretation remains a major talking point in the paddock.
But Mercedes customer squad Alpine warned F1 risks setting a dangerous precedent if the FIA backs a move by rivals to change the rules, and feels those unhappy should put their money where their mouth is and actually lodge a formal protest.
Alpine managing director Steve Nielsen said during testing in Bahrain on Friday that the protest option is clearly there – but he hoped the FIA could get the matter resolved properly beforehand.
"They've got their right to protest I suppose," he said about other teams being unhappy.
"We go to Melbourne, and if they really feel that strongly, then put some skin in the game and do something about it.
"I don't know whether the FIA will express a view on this before Melbourne. I kind of hope they do because I kind of hope the story of Melbourne isn't about compression ratios."
Super majority push
Mercedes' manufacturer rivals Ferrari, Audi, Honda and Red Bull are making efforts to propose a rule change under which testing procedures for compression ratios will be conducted when engines are hot.
This is aimed at preventing what Mercedes has done – which is have a power unit that complies with the 16:1 limit when tests are conducted in ambient conditions but can run higher when at hotter operating temperatures.
While a unified effort by four manufacturers to change the rules is in theory enough to secure the necessary super majority that could get the regulations changed, such a move still requires support from the FIA and FOM to go through.
The governing body has not yet declared a stance on the matter, although it has made clear that it wants things to be sorted before Melbourne.
But Nielsen, a veteran of F1 who has worked during his career for teams, the FIA, and FOM, believes that a last-minute rule change on the eve of the season risks setting a bad precedent in letting teams seize control of rule changes to punish others.
"The more fundamental thing for me is the way we're going about it," he said.
"If we're saying that a very clear written set of regulations can be challenged in this way, then what else is off limits? Everything's up for discussion."
He added: "People invest an awful lot of time and money, and particularly money into this, in good faith.
"And if suddenly everything can be challenged...then I think that's a whole new world which we've not been in before.
"You could say I'm biased because we've got a Mercedes engine in our car, but do we really want a sport where clearly written stuff can just be challenged because people fancy doing it? That's for the FIA to answer."
Nielsen said he had absolutely no doubt that the Mercedes engine complied with the rules as they were written at the moment.
"Some people have gone down one route, other teams have gone down another," he said.
"My personal view is I'm not concerned about it, because I think the regulations are crystal clear on when the compression ratio is measured.
"Some other people are trying to introduce different parameters to that, and that's for reasons best known to themselves.
"But we've got full confidence in Mercedes. They've built a PU in good faith with a very clear set of regulations, and we're happy with it. We trust the governing body to do the right thing."
