Renault's head of track operations Remi Taffin says the French engine supplier is confident of a vastly improved performance at this weekend's Chinese Grand Prix.
Renault endured a difficult pre-season campaign and unreliability and power problems have blighted their customer teams on occasion in 2014.
But Taffin says that new software tested in Bahrain has given them greater confidence.
"We’re feeling more confident ahead of the Chinese Grand Prix," he said. "While we know that the others are still ahead, we have made some good progress in the last two races, both in reliability and driveability, particularly in race modes.
"At the test in Bahrain we tested several new software modes that will see us closer to the limits of the Power Unit than before. In the past three races we have been some way from the edge of the performance envelope but these new modes should see us running more to the extreme. The drivers should feel improved driveability and it should also give us greater life from each part.
"Likewise we have been working on the energy management per lap, particularly in the slow corners. We know we are missing out on the straights but these new steps have given us greater traction in the turns, which should in turn extend tyre life and give greater flexibility on strategies. In fact the greater part of our work has been concentrated on race modes and performance as this is where we believe the bigger steps can be taken, rather than in qualifying.
"All of these improvements should put us a bit closer to the front in China. Of the first four races, it is one of the most difficult. The long straight is of course the major feature of the circuit, but we believe the steps taken in testing will make us less vulnerable.
"While we know it’s still an uphill battle, we feel we have hit our stride now."