Renault only ran partial F1 engine upgrade in Brazilian Grand Prix

The French manufacturer made a request to the FIA to use 11 of its 12 engine development tokens, which was accepted.

It had planned to introduce the latest specification power unit in the United States but delayed its introduction until Brazil as it continued to work on development.

It has since emerged only seven of the tokens were used on the the engine that Ricciardo raced in Brazil - and they were focused on the internal combustion engine.

The remaining four are to focus on the turbocharger, but due to part availability and compatibility with exhaust system, it was not possible to introduce that element of the update in Brazil.

Renault has yet to decide whether it will offer it for the finale in Abu Dhabi, as Red Bull would have to again consider whether the change was worth the grid penalty that would result.

Ricciardo was not very complimentary about the latest upgrade, suggesting the new specification is not any better than the old version.

Renault is keen to run the engine on-track as the data will be crucial for the French manufacturer's 2016 preparations.

It follows news that Red Bull and Renault are edging closer to continuing their partnership into 2016 following the team's failure to secure an alternative power source.

Renault's other customer Toro Rosso previously decided not to run the latest spec for the remainder of the current season as it is expected to return to Ferrari power next term, using a 2015-spec unit.