Force India is weighing up whether to continue to run its new aerodynamic package tomorrow or revert to its Turkish Grand Prix-specification car after a difficult first day of running in Spain.
The team has introduced a new aerodynamic concept for the first time today, a package that includes new front and rear wings, floor, exhaust blown diffuser, which the team is certain will allow it to climb the order as the season goes on.
But despite being confident in the package's potential, Adrian Sutil, who lost just over half an hour in the afternoon with a telemetry problem, believes that the team faces a tough decision whether to use the upgrade for the rest of the weekend.
"We have to decide today," said Sutil told AUTOSPORT whether the team will run the package tomorrow. "The upgrade package didn't work at all. It [the aero] was stalling, then gaining grip and we don't know why. The general stability of the car is not there, but I am convinced that this is the way to go. The package has potential."
Teammate Paul di Resta, who sat out this morning's first session to allow reserve driver Nico Hulkenberg mileage, admitted that the scope of the new package meant that today's practice was like a first test of a new car.
"It is [like a first test] because it's a new philosophy and it's about understanding it," said di Resta. "It's not going to work straight away, and it will take a bit to fine-tune. If we think we can do that, then we will run it. If not, we will revert back. We need to sit down, work out what direction we are going in and get the best possible racecar for tomorrow."
Despite having "a very difficult day," Di Resta is confident that the aerodynamic path that the team is heading down is the right one for the long term.
"It will definitely go forward, it's just a question of when," he said. "It's a difficult challenge to bring it to a racetrack and expect it to work the first time. You can't be that optimistic. But that is how F1 is and we will do our best to make it work."