Toro Rosso team principal Franz Tost says the new version of Honda’s power unit has moved the Japanese manufacturer ahead of Renault.

Tost said the new spec three Honda power unit, which the team tested on Friday at the Sochi Autodrom, is “really fantastic”. The team reverted to the older specification unit for the race so Honda could address any teething problem with the new unit and reduce the risk of making a further replacement and incurring grid penalties at their home race this weekend.

“Honda is making big steps forward,” said Tost in an interview shared with RaceFans. “Yesterday we had the new spec in the car and was really fantastic.”

The upgrade means “Honda is in front of Renault” now, said Tost, adding he believes its “complete package” is now superior to the current Renault power unit.

“The power unit the years before was so not so reliable, not so strong. We knew some deficiencies but Honda caught up dramatically and they are doing a fantastic job.”

Toro Rosso switched from Renault to Honda power units at the end of last year. Sister team Red Bull will replace its TAG Heuer-branded Renault power units with Hondas for the 2019 F1 season.

Renault introduced the ‘C spec’ version of its power unit earlier this year. Red Bull reverted to the older B-spec version in Sochi for reliability reasons. But team principal Christian Horner said the team will switch back to the C-spec this weekend.

“We’ve now got two engines available to us between now and the end of the year,” said Horner. “This will be the engine that [Max Verstappen] uses in Mexico, and Daniel [Ricciardo]. We’ll use the C-spec in Japan.

“Hopefully we’ll have enough components to get to the end of the year penalty-free the last five races.”

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2018 F1 season