Renault suffered a poor pre-season and lost ground through chasing reliability in the opening races of the season, during which time it suffered a series of high-profile failures as well as heavy criticism from the Red Bull team and its drivers.

Since Barcelona in May, Renault’s V6 has been stable enough to concentrate on making performance steps and scored its first podium finish of the season at Hungary.

Now it is looking for a major leap in performance with the use of engine development tokens. It has yet to use any of its allocation of 12 tokens so far in 2015, and Red Bull boss Christian Horner is expecting it to take until Sochi for the upgrade to arrive.

“We will try to do as much as we can in one go to do the big step,” Taffin told Motorsport.com. “It is not going to be Spa, I guess, not Monza – maybe it will be Singapore or Russia or the race after. Whether it is Russia or not, it will be to have a proper improvement, something you can clearly see with the lap time.

“Either you go into the season and go for big steps, or you go for small steps. And sometimes you find small steps are more costly than the big steps, because you can concentrate on the big upgrade, and that is what we have done.

“Whether we will have the big upgrade in 2015 or 2016, it is because we started later than we would have liked. The fact is we also have some [new] parts on the dyno running, and we can see the performance is there.”

Setting realistic targets

Although Taffin is hopeful of implementing the major step, most likely in October, he does not expect the kind of performance jump that will challenge pacesetters Mercedes.

“I can definitely say we will not be as powerful – I don't think we will have a better engine than Mercedes by the end of the season, but that is not the aim,” said Taffin.

“We know where we are, we know where we want to be next season for example, and this step we want to make later in the season is part of the plan to recover. You have to be cautious and organised whether and where and when you want to close that gap.

“What we use at the end of this year will be something that we keep on using for next year, but this is what we would call the main programme, but there is still some parallel programmes, and there is development you follow and if something looks promising you try to integrate it.”

Small steps continue to be made

Renault continues to turn up its engines gradually, in an attempt to maximize their performance, until the big upgrade becomes available.

“Every single race, we try to put more performance in,” said Taffin. “I think from Spa or Monza onwards, we will be at the full potential of what we have got, but you have to bear in mind that we can use new fuel and stuff like that and we don't need tokens for that.

“It is fair to say we raced [in Hungary] with a new Total fuel, and that is part of the development programme.

“The plan is there. The fact is we’ve got some parts on the dyno, and we see progress, but until we are sure that the big step is there – ready to go – we will not put it on the car.”

Interview by Oleg Karpov