Boullier believes Honda have a plan to improve engine

Honda have revealed that they have a plan to dramatically improve a crucial element of its current power unit, according to McLaren team boss Eric Boullier.

The struggling Japanese marque's F1 chief Yasuhisa Arai left Spa-Francorchamps with a red face, having stridently predicted that an upgraded engine in Belgium would match the one now fielded by Ferrari.

Ultimately, it was a woeful weekend for the Anglo-Japanese collaboration, with some reports mentioning the top speed deficit as actually in the two-dozen kilometres per hour range.

McLaren chief Boullier, however, is upbeat.

"You can see that the big step taken by Ferrari since last year was to improve the MGU-H," said the Frenchman, referring to the energy recovery system that converts heat from the turbo.

"It seems that Honda has a plan to have a very good (MGU-H) system next year," Boullier is quoted by Spain's El Confidencial.

Elsewhere, following meetings at Spa-Francorchamps, sources report that F1 could be close to an agreement that would allow struggling manufacturers Honda and Renault to close the gap next year with less limited development.

It is rumoured the development could also bring a fifth carmaker into the sport.