Formula 1's governing body has said that it is serious about 'performance convergence' when it comes to the engines in the sport.

Part of the new rules package agreed in the past days is that the different power units built by Mercedes, Ferrari, Renault and Honda should all differ by no more than "three tenths" per lap.

The three tenths factor was declared by the FIA's engine chief Fabrice Lom, speaking at the scene of the Spanish Grand Prix.

"We will not look simply at laptimes," he said. "We have simulation tools by which we can calculate the performance of the engines."

Lom is quoted by Speed Week as explaining that during an early monitoring phase early in the season, the different engines will be compared.

"If we have the impression that the engines vary too much, we will submit a report to the strategy group, who will take the right steps," he added.

One early suspicion, however, is that a dominant manufacturer like Mercedes might 'sandbag' during that three-race monitoring period.

"That's one hell of a tactic!" exclaimed Renault's Cyril Abiteboul, insisting that he thinks performance convergence by the FIA's method is in fact "achievable".

Another detail of the new engine rules is that manufacturers like Honda will be compelled to offer customer engines in the event that teams are left without engine contracts.

Ron Dennis, however, has said that he intends to enforce McLaren's exclusivity, even though Honda sounds open to supplying customers.

"We don't have concrete negotiations," said Honda's Yusuke Hasegawa on Friday, "but we do have conversations with some teams.

"Our position is we have to wait for the situation to change, but I think we have an obligation to contribute to the Formula 1 society."

The Spanish Grand Prix gets underway at 1pm BST on Sunday.