Adrian Newey has admitted that packaging problems with the new RB10 contributed to Red Bull's troubled Jerez Formula 1 test.
The new car managed just 31 laps during the first pre-season test in Spain two weeks ago, with its own exhaust issues compounding the difficulties that hit engine supplier Renault.
Newey, Red Bull's chief technical officer, confirmed that the team's major problem was the heat of the exhaust setting fire to bodywork, which came on top of the issues that afflicted all three Renault teams that ran at Jerez.
"What stopped us at Jerez, on our side as opposed to Renault's side, was a problem where the bodywork local to the exhaust was catching fire," Newey told AUTOSPORT.
"It's a problem which hopefully we can get on top of ready for Bahrain.
"It was really a lack of time [that caused the problem]. It was something that we could have proved out on the dyno if we had managed to get everything together earlier.
"But Renault have been up against it in terms of their use of the dyno, we have been up against it making the parts in time.
"So I think had we been a couple of weeks further ahead then that could all have been done in private on the dyno. But unfortunately it was done in public."
Renault has also had to work flat out since the test to solve both hardware and software problems in its engines, which afflicted all three of its cars that ran at Jerez.
RENAULT'S COOLING NEEDS "PARTICULARLY LARGE"
Newey accepted responsibility for the exhaust problem, although he stressed that Renault's 1.6-litre turbocharged V6 engine is particularly demanding in terms of cooling.
"Hands up on our side, that was a Red Bull problem," said Newey.
"It was, you could argue, a result of aggressive packaging but we felt that we needed to take a few risks to try to get a good package that would minimise the aerodynamic damage of this very large cooling requirement.
"The Renault seems to have a particularly large cooling requirement.
"Everybody of the three engine manufacturers will have a different target for how hot their charge air is going back into the plenum and Renault have given us a fairly challenging target.
"It has all sorts of advantages if we can get there, but it is not easy to achieve."
Newey also admitted that the packaging demands of the new engines are an especially big challenge.
"It is certainly a challenge to package everything in," said Newey.
"The radiator area that we need to cool the charge air from the turbo and additionally all of the extra cooling we need for the electrical side of things, the batteries, the motor generator unit and so forth, the control box... It means that the radiator area is roughly double last year's car with the V8.
"So trying to package that in without compromising the aerodynamics too heavily is a challenge."
AUTOSPORT Live will be covering this week's Bahrain Formula 1 test as it happens, starting from Wednesday morning