Toro Rosso F1 team changing working methods after 2015 troubles

The Faenza-based squad set an ambitious target of finishing fifth in the constructors' championship this term but it ended the year seventh.

The Renault power unit contributed to reliability problems but Tost said there are improvements that can be made on the team's side from the bottom up.

"It's about changing the way we work," Tost told Autosport.

"The people are doing a good job, we just have to go into the detail to understand everything.

"A reliability issue very often starts in the drawing office and that means the drawing office must take care.

"Then it is going to the assembly and sometimes here, they have made some not direct mistakes but some small issues which caused problems.

"Then it is going to the racetrack, to the mechanics and how they assemble the car and dissemble the car.

"It's the attention to every small part and this is where we have to become better.

"It's a question of the process itself and we had a couple of meetings last month and the weeks before.

"We discussed everything in an open way and hopefully we can sort out these issues for 2016."

Next year, Toro Rosso will switch from Renault to Ferrari power, albeit 2015-spec units.

Tost believes if the team makes the required changes to its procedures, it can challenge for fifth - especially as rookie drivers Max Verstappen and Carlos Sainz Jr go into their second years.

"I am convinced about that [challenging for fifth] next year as I'm sure we will have a competitive car," added Tost.

"We also have two great drivers who are more experienced, will know the racetracks and how F1 is working, which will help a lot, and the team will improve by focusing on detail.

"I also expect the power unit will be very good, very competitive so there is no reason why we should not achieve that goal."