Daniel Ricciardo will revert to the older specification Renault engine for the Abu Dhabi Grand Prix weekend, following a disappointing outing for the new unit in Brazil.
The Australian took a grid penalty in Brazil to use a new upgraded internal combustion engine at Interlagos, but the improvements delivered little, if anything, on track.
He even reckoned that it was slower in a straight line than the older version that had been used by teammate Daniil Kvyat.
Following detailed analysis of the performance of the Spec-B unit, both Renault and Red Bull have agreed that they would be better off going back to the older Spec-A version for Yas Marina.
As the older engine has already been used, there will be no grid penalty for changing it.
Renault F1 managing director Cyril Abiteboul admitted in Brazil that the progress of the Spec-B engine had perhaps been hindered by the troubled relationship with Red Bull, and the fact that not all of its components were used.
"It is true that recent history and uncertainty with Red Bull have loosened the technical collaboration that there was between our respective teams," he said.
"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."
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