Christian Horner revealed that Red Bull Racing had uncovered 'correlation issues' between its wind tunnel readings and the on-track performance of its RB13.
Both Daniel Ricciardo and Max Verstappen have underlined their car's delicate balance and its very narrow set-up window.
While the gap with frontrunners Mercedes and Ferrari appears reduced in Bahrain, Red Bull still remains at a fair distance from its rivals.
"For the first time in a long time, the correlation between CFD, the wind tunnel and the race track does not match.
"We get three different sets of data," Horner said.
Design changes to several areas and parts of the RB13 are in teh works but won't appear until he Spanish Grand Prix at Barcelona in May
"We have understood our chassis problems," Helmut Marko told Auto Motor und Sport.
"But we need to wait until Barcelona for the solution. We are too fast on the straights," Marko admits, referring to the RB13's low drag but also low downforce characteristics
Commenting on the prospects of Red Bull's modified car, Horner confirmed that "The step will be significant".
GALLERY: All the pictures from Saturday in Bahrain
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