
The FIA will find it 'very awkward' to impose any restrictions on Mercedes' power unit amid a row over their engine's compression ratio, according to former Red Bull operations chief Richard Hopkins.
A dispute over Mercedes' newly-designed power unit erupted before and during the final two pre-season tests in Bahrain, where the Silver Arrows largely set the pace.
One of the new regulations for 2026 surrounds the compression ratio in use on the power unit, which measures how much the air-fuel mix inside a cylinder can be compressed.
A default maximum ratio setting of 16:1, in ambient conditions, has been put in place by the FIA for all 11 teams throughout the 2026 season.
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But Mercedes' rivals are arguing that the 2021 constructors' champions have found a 'trick' which allows them to exceed that ratio in higher temperatures.
Mercedes team principal Toto Wolff has strenuously denied accusations that they have breached the FIA regulations, and the Austrian has stated that his engineers were in dialogue with the FIA throughout the design process.

During the second Bahrain test, the F1 Power Unit Advisory Committee confirmed that they had submitted a proposal which would require engines to meet the 16:1 limit while in a representative operating temperature of 130 degrees Celsius.
It was further stated that a vote would be held among power unit manufacturers on the proposal, which would come into effect from August 1, 2026 if passed.
Four out of the five power unit manufacturers - Mercedes will be given a vote - must vote in favour of the proposal for it to pass.
For their part, the FIA have stated that there is no indication of wrongdoing by Mercedes, and that other power unit manufacturers have not stated their belief that any regulations have been breached.
There also remains a question over how the FIA could logistically enforce a major power unit change mid-season, given that allocations have already been set and designs are already in place on the cars.
Hopkins, who was a mechanic for the likes of Benetton and McLaren before becoming head of operations at Red Bull, believes that power unit manufacturers and the FIA may have to have 'very awkward' arguments over the dispute given the voting percentages needed - especially as Alpine, McLaren and Williams all use power units supplied by Mercedes.

"Formula 1 is, and always has been, and always should be, finding loopholes in regulations," Hopkins told SPORTbible, via betting sites comparison platform Bojoko.com.
"To be honest, I think the day we stop that, and outlaw that, then Formula 1 stops. They [Mercedes] found a loophole in the regulations, and congratulations and well done to them.
"As always, the people that are complaining are the people that didn't find the loophole, right?
"It's challenging because it's not just Mercedes, and there's three other teams [that they supply power units to].
"I think it's going to be a very awkward argument to be had. If it was one team and one team only, and there have been examples of that in the past, and they've changed regulations mid-season with a gentleman's agreement... this one is a little bit harder because it's the within the engine.

"The only way you can arguably modify that is to give up some penalty - [you can] restrict power if you can calculate the advantage within the engine, you get all four Mercedes cars to turn down from 10 to nine, or limit the revs, or something like that.
"Personally, I don't agree with that.
"In 2009, with the double diffuser, that was a great bit of innovation. And everybody looked at the regulations afterwards, Adrian Newey included, and went, 'Oh my God, how did we not see that?'
"I think it would be mightily unfair if they [Mercedes] got penalised for being ultimate innovators."