Nikolas Tombazis, the FIA technical boss, has warned that new regulations to be introduced next season in a bid to improve overtaking will slow the cars by around 1.5s a lap.
"We expect to about lose 1.5s per lap maybe, that sort of order, that sort of order, he warned ahead of this weekend's Spanish Grand Prix at the Circuit de Barcelona-Catalunya, the track where the new aero will make its debut next year in pre-season testing.
"It is a bit difficult to predict exactly the amount of development the teams will put on," he admitted, "but we certainly expect to lose performance, but that sort of magnitude."
Ironically, the move comes just a year after new regulation were introduced to speed up the cars however, a dearth of overtaking in Melbourne, not to mention a 50% drop over the course of 2017, has led to the changes even though a number of teams are against them.
It's not a matter of black and white and whether you can follow or you can't," said Tombazis, "we hope to make an improvement in close racing and to be able to allow cars to follow more closely.
"The end plate is significantly simplified," he continued, referring to the front wing, "all the top furniture, the little winglets that you can see and various vertical fins that produce a range of vortices that are intended to control the front wheel wake, these are being eliminated. And the wing profiles themselves, they have to follow certain rules that makes them simpler and hence less able to control the wheel wake.
"In our studies the wheel wake is what then affects the following car, and losing control of that, we feel, is what is going to make a big step in improvement," he claimed. "But as I say, I am not expecting cars to be bumping each other like touring cars, it is just going to make a step forward.
"I would also add that the way the development is going in current racing, one of the key tasks of aerodynamicists in an F1 team is to move the wheel wake further outboard for the benefit of their own car. The more outboard it is, the less it affects the diffuser and rear wing, and again performance. So that is the key objective.
"That key objective is also bad for the following car, so our expectation is that if we didn't do a rule change, the next two years in '19 and '20 would gradually be getting worse.
"Part of the rule change was to stop that trend and make a step change," he admits. "We feel that these performance characteristics would actually be worse for '19 and '20 if we did nothing."