Mercedes GP boss Ross Brawn has admitted that his team's F-duct system is still not working as efficiently as it should.
Although Mercedes introduced a version of the McLaren-pioneered system in the Chinese Grand Prix in April, the German squad is still not completely satisfied with how it's working.
Brawn admitted the Mercedes F-duct is still generating too much drag on the straights, something the team will be hoping to rectify for the next race in Canada, where top speed is crucial.
"I think when you get the F-duct working properly you have both. You have the downforce in the corners and then turn drag off on the straight. At the moment we are not turning off enough drag on the straight," said Brawn after the Turkish Grand Prix.
"As we said before, McLaren were clever enough to come up with the concept and have a lot more experience of it. You are seeing certain teams abandoned in Turkey and when it works properly it is a very, very powerful tool - and we are persevering with it.
"It works in a certain way with it, but not giving us the full benefit yet. We have the right compromise with what we have. We will be a little bit vulnerable with straightline speed but best compromise for that time and consistency on tyres."
Despite the concerns about the F-duct, both Nico Rosberg and Michael Schumacher are hopeful of a strong result in Canada.
"Our Mercedes-Benz engine will certainly be a big help on the main straight," said Rosberg in a team preview. "We will have some further upgrades for the race weekend and the fact that the circuit characteristics are quite different from Istanbul Park makes me go there with high hopes. I think we might just put in a great result."
Schumacher added: "The Circuit Gilles Villeneuve is all about top speed so we have worked very hard on this, especially as we know that we are not right at the top in that area. However I am convinced that we will be able to get the best out of our package."