Red Bull deciding whether to race F-duct
The team used an initial version of the downforce-stalling concept in practice in Turkey, but then decided to leave Adrian Newey in the factory to develop it rather than take the famous Briton to Canada.
The RB6 was fitted with a developed F-duct on Friday in Valencia, where Sebastian Vettel came within mere thousandths of beating Ferrari's Fernando Alonso to top spot.
"When the system is working, it is a big help," German Vettel is quoted as saying after practice by the German news agency SID.
As for how it worked on Friday, he added: "In the morning it was still not so good, but in the afternoon better."
In a post-session statement, the 22-year-old added: "We need to see if we keep the F-duct in the car, we need to confirm that, but all in all I think the pace was promising today considering this shouldn't be our strongest track."