Race stewards again rejected the protest, just as a different set of officials had in Melbourne, and BMW-Sauber said they would appeal.
The International Automobile Federation (FIA) international court of appeal is already due to meet in Paris on April 14 to rule on appeals submitted by Red Bull, Renault and Ferrari against the other three teams’ rear diffusers.
All Formula One cars have diffusers, which channel the air smoothly under the car and out of the rear to increase downforce.
However, Brawn and the other two teams have come up with a novel approach that stewards have accepted as legal but rivals say goes against the spirit of the new regulations.
BMW-Sauber team boss Mario Theissen said Saturday’s appeal was purely procedural.
"It was just a formal issue, in order to make sure this race is taken into consideration at the appeal like Melbourne," he told reporters. "Nothing more than that.
"We want to make sure the court of appeal decides on both events."
Brawn team owner Ross Brawn, whose team finished one-two in Melbourne and secured pole position at Sepang, said the latest protest merely meant that six stewards rather than three now agreed the cars were legal.