Renault will not release an updated engine to its customers until the Russian Grand Prix in October, according to Red Bull team boss Christian Horner.
The Milton-Keynes based squad have endured a difficult 2015 to date, with numerous power unit issues leading the company to consider their future in the sport.
Relations between Renault and Red Bull have been fractious since the beginning of the season, with both parties accusing the other of either deceit or demotivation.
The two outfits have found common ground in recent weeks, with Renault focusing their development on improving engine lifespan in the first half of the 2015 season.
However, Horner confirmed on Friday that he does not expect the French car manufacturer to use one of its 12 available engine upgrade tokens before Formula 1 arrives in Sochi for the Russian GP.
“I don’t think anything is scheduled now before Sochi,” the 41-year old said.
“That is probably going to be the earliest we will see any form of development or use of tokens.
“So the engines we have at the moment are what we have to live with for the time being.
“Engines four and five are what the drivers have been using between Friday and Sunday racing.”
Grid Penalty
Daniel Ricciardo, who suffered another engine failure in Friday’s second practice, will reinstall his fifth engine of the season into his car, after previously debuting the unit at the Austrian GP in June.
Should the Australian require a sixth engine, which seems highly likely with power circuits such as Spa-Francorchamps and Monza yet to come, a 10-place grid penalty will immediately be issued.
Horner hinted that it may be difficult to not incur another grid penalty before the Russian GP, however stated that Renault were making in-roads to improve the powertrain.
“Unfortunately, Ricciardo has lost engine four, so he has only got engine five which came into service for the first time in Austria to get him through the next few races,” Horner added.
“Only time will tell if we can get to Sochi without incurring another penalty before introducing a new upgraded unit.”
“Renault would be the first to admit they are not happy with where performance or reliability has been with this engine,”
“They are making progress, they are making strides. The problem with the engines, unlike the chassis, is they are long lead-time items.
“Renault have got some strategic decisions to make over the coming weeks in terms of the direction they want to go not just for 2016 but for beyond that.”