Jan.28 (GMM/Inautonews.com) Red Bull’s engine supplier Renault says it has made big changes to its turbo V6 engine for the 2015 season.

The French marque struggled as the new rules dawned last year, winning only three races compared to dominant Mercedes’ sixteen.

It prompted big organisational changes at Viry-Chattilon and also major upgrades for the 2015 engine, despite the fact the 32 performance ‘tokens’ could actually have been deployed throughout the forthcoming season.

“We have used the majority of the tokens for the first race,” said technical boss Rob White, “and our use of tokens during the course of the season will be relatively modest.”

He said it is not clear how much better the 2015 engine will be, but managing director Cyril Abiteboul is targeting an improvement on Red Bull’s three wins last year.

The marque’s F1 present Jerome Stoll said the 2014 season was a “lesson” for Renault that it needed to restructure and fundamentally change its V6 design.

Along with Red Bull, Renault’s only other remaining customer is Toro Rosso, after Lotus switched to Mercedes and with Caterham looking unlikely to survive.

“The Renault you see this year is consequentially very different to 2014,” Stoll revealed.

Abiteboul added: “We believe we have made a very big step in performance and will be more reliable.

“We may not have erased all the gaps, but we are confident that we have gone a long way to making up the deficit of last season.”

White agreed that the 2015 engine is “very different” to last year’s, having “upgraded every system and subsystem”.

“In short,” he explained, “there are very few carry over pieces between the 2014 and 2015 power units.”