Formula 1 teams are set to resist a push by the FIA to change the blown diffuser regulations this year.
The FIA intends to prevent teams from continuing to blow exhaust gases through their diffusers when a driver is off-throttle. The ban had originally been intended to come into force at this weekend's Spanish Grand Prix, but that plan was dropped after some teams complained, and the matter will now be discussed in next month's meeting of F1's Technical Working Group.
Although the FIA is set on ensuring that the blown diffuser rules are changed, leading teams say they do not agree with what is happening. Renault team principal Eric Boullier, whose team has the most complex use of a blown floor on the grid with its forward facing exhaust layout, does not understand why there is a need for the change.
"This has come as a surprise, completely out of the blue," Boullier told AUTOSPORT. "I understand some technical reasons from Charlie [Whiting, FIA technical delegate], but we have demonstrated that we are not on the same page on this. For me it is strange that it came out of the blue like this, as a change of the regulations during the season is always tricky. And even if Charlie claims it is not a change of the regulations, it looks like it is.
"It doesn't cost a lot of money to do it, it is just mapping of the engine. Everybody is chasing performance, so I don't see why we should have to change it. But we are not the regulator of the championship. That is the FIA."
Red Bull Racing team principal Christian Horner said he doubted there would be much support from teams in the TWG to go ahead with a ban.
"I think is a responsible thing to discuss it in the TWG," explained Horner. "I think that it is the right forum to discuss it, and I am sure there will be some positive debate in there.
"Whether it is something required for this year or next year, I doubt that you will get unanimous consent for this year, that would be my personal opinion. But we will see."
When asked if Red Bull Racing had lobbied the FIA to delay the ban, Horner said: "We took a fairly pragmatic view. We certainly felt last week that it was something the FIA wanted, so our opinion was it was going to affect lots of teams in an equal manner and maybe some worse than others, but we weren't overly concerned about it. However, it was time consuming to be spending time thinking of an alternative when that wasn't required."
Although teams like Red Bull Racing are understood to use around 45 percent of throttle flow for the blown diffuser when the driver is off the accelerator, sources suggest that Renault's use is as high as 95 percent – so a limit of 10 percent, as proposed by the FIA, would require a major overhaul of the way it operates its car.
"We would definitely be affected," said Boullier. "So we will resist, yes, for sure. But, in the end, we have to respect the FIA decision – and Charlie has agreed to listen, to discuss and to understand. If, after that, he still wants to get rid of it, then why fight more? They decide on the regulations and if they want in the end to clearly get rid of this, then we have to deal with it."