Off-throttle diffuser ban plans still on

AUTOSPORT understands that the FIA wrote to F1 teams on Saturday morning in Montreal informing them that it was committed to not allowing them to continue off-throttle use of blown diffusers.

The FIA originally intended to ban the systems from the Spanish Grand Prix, but that decision was delayed after the governing body was made aware of 'unintended consequences' of such a move.

However, ahead of a meeting of the F1 think tank Technical Working Group in London on Thursday, the FIA says that it is set on its course of action.

As well as outlining its decision to make off-throttle blown diffusers illegal from the British Grand Prix, it suggests a change to the technical regulations for 2012 that will outlaw teams from using blown diffusers at all.

Williams technical director Sam Michael confirmed that the teams had been informed of the plan - and that Thursday's meeting would be about how best to implement the FIA's decision.

"The FIA has made its position very clear," said Michael. "They want to talk about the fine details on Thursday, but what Charlie [Whiting, FIA technical delegate] is saying is that hot blowing is banned and cold blowing is banned from the Silverstone GP onwards.

"For 2012, the exhaust system must exit behind the rear wheel centre line, actually 330mm behind, so right out the back of the diffuser.

"That means there cannot be any exhaust influence on the diffuser. That is what the FIA has clarified and then Thursday is about implementation."

Whiting said at the Spanish Grand Prix that the FIA acted on the blown diffuser situation because it was worried teams were exploiting that area of car design too much.

"It became apparent to us, through examination of data, that what we thought was a fairly benign feature was turning into something that was being used, in our opinion, illegally," he said during a media briefing.

"An exhaust system is there for the purpose of exhausting gasses from the engine and when you're off-throttle, it isn't doing that any more. Therefore it's being used to influence the aerodynamic characteristics of the car. We think arguably, this infringes Article 3.15 of the technical regulations."