Some Renault-powered F1 drivers could run out of engines later in 2014, the French supplier has admitted.
Renault chief Rob White said the French marque's recovery from its early-season struggle for power and reliability is still ongoing.
"At the first test we were miles off. We were in a crisis," he admitted to Germany's Auto Motor und Sport, "but we didn't panic.
"We set up a plan to close the gap. Since then we have made progress but unfortunately not quite enough," White acknowledged.
And those efforts to end the crisis have had a price, he added.
"Within the individual teams, we have consumed more components within the power unit than we had planned. It means that the teams are at different development cycles.
"For some it might be tough to stay within the allowed five units (per driver per season)," White said.
Although world champion Red Bull's struggles have had the highest public profile, correspondent Michael Schmidt claims Lotus is in fact the worst-affected Renault team, followed by Caterham.
Despite the current problems, however, White is confident Renault can continue to close the gap -- and he insists the horse power advantage held by Mercedes is not even a target too far.
"There is nothing in our engine concept that prevents us from being the best," he said.
However, it has been said that Mercedes stole a march in the fundamental layout of its V6 concept, uniquely situating the turbine and air compressors at either end of the 'power unit'.
White insisted: "It's not that we didn't think of arranging it that way. We don't consider it the match-winner."
Renault's F1 boss Jean-Michel Jalinier agrees: "We have not had any great eye-opening experience in which we had to admit to ourselves that we were caught out."
Rather, White said Renault's 2014 problems have been because "we were late to reach our goals, or because we underestimated the risks or overestimated our capacity to solve the problems in time".
Turning up F1's volume 'absurd' - Minardi
Gian Carlo Minardi has slammed as "absurd" F1's efforts to turn up the volume of the new turbo V6 engines.
Mercedes fitted an unseemly, trombone-shaped exhaust to its car at this week's Barcelona test, but it failed to deliver the sound boost that many in F1 - including Bernie Ecclestone and race promoter Ron Walker - are seeking.
Minardi, the founder of Faenza based team Toro Rosso's original guise, is not impressed.
"I find it absurd that the focus is on the noise, when it definitely is not the primary problem," he said.
66-year-old Minardi said teams should stop the efforts to turn up the volume and focus instead on being "more competitive".
"In Spain we saw a gap of 49 seconds between Mercedes and the first pursuer, Red Bull. An abyss," he told his official website.
Indeed, many are predicting that Mercedes' advantage is so big that the German team could go on to win every single race on the 19-grand prix 2014 calendar.
A 100 per cent winning record is unprecedented in F1 history, but even Mercedes team chairman Niki Lauda acknowledges that it is a possibility in 2014.
"At the moment it looks like it," the F1 great told Osterreich newspaper.
"I don't want to sound arrogant, but I am calm," said Lauda. "I think if you have the pace advantage that we had at a circuit like Barcelona, then the others need at least four to five races to catch up."
And he thinks new championship leader Lewis Hamilton, who has won the last four grands prix on the trot, is likely to beat Nico Rosberg to the 2014 title.
"Lewis is in a league that I have rarely seen," said Lauda. "Flawless. Beating him at the moment I would say is almost impossible, but thanks to his tactical approach I think Nico can get closer."
'Something wrong' with original chassis - Vettel
Sebastian Vettel has admitted there was "something wrong" with his original 2014 chassis.
After Barcelona, where the German impressed at the wheel of Red Bull's winter testing monocoque, it was reported that the team had discovered a 'bend' in the car with which Vettel struggled during the first four races of 2014.
Red Bull immediately denied the report.
But the story has now been repeated by the major German daily Bild-Zeitung.
Vettel is quoted as saying: "I knew there was something wrong. I had lost all trust under braking for the corners and accelerating out of them."
Dr Helmut Marko, Red Bull's outspoken director, does not deny Vettel's claim that something was "not right" with the car Vettel originally dubbed 'Suzie'.
"The chassis was not really bent, but in some places it just was not one hundred per cent right."
Marko said Vettel will stay at the wheel of the winter testing chassis for the time being, "but soon he will get a new one".
Reigning quadruple world champion Vettel is not even ruling out his first win of the season next weekend in Monaco.
"At Monaco you don't need as much engine power as you do at other circuits," he is quoted by SID news agency.
"Maybe some rain could help us as well. There is always a chance to win," added Vettel.
Lauda furious as Red Bull drop name from F1 circuit
Niki Lauda has hit out at Red Bull for dropping his name from a corner at the returning Austrian grand prix venue.
Now called the Red Bull Ring, the former A1-Ring was demolished and totally rebuilt by the energy drinks company, and next month it will host its first grand prix since 2003.
Prior to the Red Bull takeover, one of the corners at the A1-Ring was called the Niki Lauda Kurve, in honour of the Austrian great and triple world champion.
Now, the same corner has been renamed Pirelli. Also gone is the Gerhard Berger Kurve, replaced by Wurth, a German tool company.
"I'm very disappointed," Lauda told Kleine Zeitung newspaper.
"I can only presume it is because I am now at Mercedes and we are beating Red Bull," he added.
So far, the Jochen Rindt Kurve - named after the posthumous 1970 world champion - has survived the Red Bull Ring's search for sponsor dollars.
But correspondent Gerald Pototschnig said even that corner could be renamed if a sponsor makes an attractive enough offer.
"As punishment," the angry Lauda said, "Mercedes will be happy to celebrate a one-two in Spielberg."