The FIA has banned the aggressive blowing of exhaust gases when drivers are not pressing the throttle, according to rumours on Tuesday.
Many teams, including grandees Red Bull, McLaren, Ferrari, Renault and others, have devised sophisticated exhaust layouts and engine maps for 2011 that exploit the aggressive blowing of gases through the diffuser when the drivers are off the throttle to maximise downforce in corners.
But according to the latest rumours, the FIA has issued 'Technical Directive 15' that means maximum throttle is limited to just 10 per cent when the driver is not pressing the throttle.
It is believed the directive was issued last week with immediate effect.
F1 teams have been contacted for confirmation.