Daniel Ricciardo will be running the older specification Renault power unit in this weekend's Abu Dhabi Grand Prix.
Following a disappointing race in Brazil with the latest spec engine, the Red Bull Racing stalwart expressed his disappointment with the improvements implemented by Renault, and which centered around the unit's combustion engine.
Extensive analysis of the Spec-B unit has convinced Renault and Red Bull that reverting to the A-spec would better serve the Milton Keynes outfit's interests at the Yas Marina track, with no imposed grid penalty as the unit has already been used.
Renault F1 managing director Cyril Abiteboul alluded to the manufacturer's dissolved partnership with Red Bull as part of the reasons why the power unit's improvements lacked a performance impact.
"It is true that recent history and uncertainty with Red Bull have loosened the technical collaboration that there was between our respective teams," Abiteboul commented.
"Our dialogue has almost stopped. It was only fair for next year, but maybe where we should have been a bit more careful was that it didn't stop for this year.
"It meant we were not maximising the performance improvement of that engine, because if you change one element of the power unit you need to think of the side effect of all the other elements of the power unit."
Unfinished business: the scores still to be settled in Abu Dhabi
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