Renault running 'weeks behind'
Renault have revealed they are still "weeks behind" as the new Formula One season looms large on the horizon.
The French manufacturing giant have endured a range of issues over the course of pre-season testing to date, both in Jerez last month and in Bahrain last week.
That has played a part in a lack of mileage for all of their partner teams in Lotus, Toro Rosso and Caterham, and primarily reigning world champions Red Bull.
Chief amongst their problems have been hardware woes with the new-for-2014 ERS (energy recovery system) and software difficulties with the power units.
Although Renault made progress in the second test, ahead of the final four-day test that starts in Bahrain on Thursday, they admit they are off the pace of the two other power unit manufacturers, Mercedes and Ferrari.
"We have had some setbacks, but we have definitely made progress and have taken several steps forward," said Rob White, Renault Sport F1's deputy managing technical director.
"The changes have improved the PU (power unit) behaviour in the car and we accumulated valuable mileage.
"There were stoppages, on our side and on the chassis side as well, but we ironed out some important faults and allowed the teams to gain crucial experience of the car as a whole.
"While we are not at the level of operation and performance we would want to be, we have a more solid basis to work from."
Although White feels Renault "are moving in the right direction", they "are not back on schedule".
Highlighting the problems, White added: "The challenge is to improve the rate of progress because the gap to where we wanted to be at this stage remains substantial.
"We are some weeks behind, and we acknowledge it will take time to unlock the full performance of the PU.
"We are working hard to get there and we are determined to succeed.
"We remain confident in the PU and its sub systems, we are just not at the level of operation and performance we want to be.
"The immaturity of the PU, combined with the time lost to incidents, means the chassis work to prepare for the season is also behind schedule.
"From this point on we must pursue and accelerate an upward curve, with the team working night and day to solve our problems."