The FIA has warned F1 teams that any attempt to exploit special engine modes to purposefully enhance exhaust flow towards a car's main wing will not be permitted.
On the back of Renault's 2018 design, which features an angled exhaust directed towards the heat-shielded leading edge of the rear wing of its R.S.18, teams have questioned the legality of the French team's concept.
FIA race director Charlie Whiting has confirmed however that Renault's layout complies with F1's technical rules - although many suggest the scheme is certainly not in the spirit of said rules.
The governing body has now made clear that special engine modes, such as the off-throttle blowing which prevailed between 2010 and 2013, shall not be tolerated this year.
Whiting has given the green light to Renault's approach, but insists he will be particularly attentive to engine usage this year.
"I think it is absolutely minimal what they [Renault] will get from it," said Whiting told Motorsport.com.
"I don’t see any problem with it provided we are sure they are not operating their engine in a false mode – a mode that wouldn’t be normal.
"We have to accept that there is and always has been some exhaust effect, but obviously in 2012/2013 it was massive.
"We’ve chipped away at that and one of the things for the 2014 [turbo hybrid] rules was to make sure there was no effect from the exhaust – but there must be a little one.
"We will have to deal with that, and we will see during the course of the year whether we need to do something to minimise that."
Whiting admitted that this year's ban on monkey seats, the small rear wing structure which helps direct the exhaust flow towards the main wing, hasn't deterred designers from exploiting the blown wing concept.
"We were concerned with exhaust blowing last year," said Whiting.
"With the wings becoming 150mm lower than they were in 2016, there was more benefit to be gained.
"That is why we put the exhaust pipe in the middle and with a minimum angle. Teams managed to build monkey seats, which we managed to get rid of by changing the bodywork regulations.
"But there was still a little window of opportunity. You know what teams are like: if you take one thing away they will try to get 10 percent of what they had. But they will still do it."
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