Red Bull RenaultRed Bull Racing's title hopes could be boosted if engine supplier Renault is given the green light to make modifications to its power unit that have been lodged for FIA approval. Although Formula 1 operates under an engine freeze, the Renault power plant has fallen behind competitors over recent seasons as its rivals have made minor tweaks to their power units.

Engine performance was supposed to be equal, but it is now believed the spread of horsepower between the manufacturers could be as much as 30bhp.

Red Bull Racing chiefs have made no secret over the winter that they hoped engine performance could be equalized this year – and sources have revealed that moves have now been made by Renault to do so.

AUTOSPORT understands that Renault has written to the FIA to request a series of improvements to be made to its RS27 power unit on both reliability and cost reduction grounds. A team source said that this application was made under the "fair and equitable" grounds that are laid out in F1's regulations for modifications.

Although the improvements have been requested for reliability and cost reduction reasons, it is likely that such improvements would bring performance benefits, too.

Red Bull Racing team principal Christian Horner declined to comment about the situation in Bahrain, but he did admit in the build-up to the weekend that something needed to be done.

"There is an issue with the engines and it would be a great shame if, under the engine freeze, engine performance is going to dictate the championship," he said. "Renault needs to find a solution and quickly."