The FIA has moved further to clamp down immediately against aggressive exhaust blowing.
It was already known that so-called "hot blowing", involving the aggressive blowing of engine exhaust through rear diffusers when the driver is not on the throttle, will be effectively banned as of Silverstone next month.
But Germany's Auto Motor und Sport reported on Tuesday that another element of exhaust blowing will be banned immediately.
From Valencia this weekend, teams will no longer be able to use extremely aggressive hot-blowing in qualifying, and then switch to a more engine-friendly setting for the Grand Prix.
McLaren said recently it suspected precisely that practice was giving Red Bull's RB7 its qualifying advantage.
Jenson Button told Blick: "They (Red Bull) use the exhaust gases into the diffuser non-stop on a qualifying lap, but not in the race."
With Red Bull's aggressive qualifying mode, they are gaining a good half a second
And Auto Motor und Sport quotes team boss Martin Whitmarsh as adding: "With Red Bull's aggressive qualifying mode, they are gaining a good half a second."
Red Bull consultant Helmut Marko said on Austrian television Servus TV: "If the others cannot copy it, they can try at least to have it banned."
But the Austrian said he suspects Ferrari will benefit the most from the FIA's clampdown.
"I think McLaren will be affected less, or similar to us as they have a very good copy (of the Red Bull exhaust)," said Marko.