Ferrari's Vettel confident Allison exit won't hurt 2017 F1 car

It was announced on the eve of July's German Grand Prix that Allison had left the F1 team after three years, with Mattia Binotto moving from his role as engine boss to become chief technical officer.

Ferrari's head of race activities Jock Clear said at the time the team would have to "work hard to cover the gaps" created by Allison's departure.

Vettel says news of the exit was tough to take, but the German does not believe it will throw development of Ferrari's 2017 car, even following delays in finalising the revamped technical regulations.

"Next year's car project started very early for anyone because it is so different," said Vettel.

"It took a while at the beginning of the year to know exactly what is going to happen for next year.

"It's not just one person, so obviously it wasn't easy for the whole team to digest that James is not there anymore.

"You can imagine he had one of the key roles and an influence, but it didn't impact much on what was going on behind the scenes in terms of looking forward.

"Back at the factory we had a plan, which we are following for a long time, for what is going on for next year."

Ferrari started 2016 with hopes of challenging Mercedes, on the back of a vastly-improved '15 season in which Vettel won three races.

However, with three grands prix to go, it is winless and rather than challenging for top spot has fallen behind Red Bull to third in the constructors' championship.

Vettel conceded this campaign has been inconsistent but insisted Ferrari is in a better place than when he joined from Red Bull at the end of 2014.

"You will always get measured by what you achieve on the day," he said.

"We've had some good days this year, we've had some not so good days. It's part of the game.

"But it must not distract from what is really important, which is what is going on in the factory.

"In that regard, things are improving. I've been on board for nearly two years and things are going a lot better than they used to be, two years ago.

"It would be nice to have everything done and sorted on the car and have the result tomorrow, because then the general perception would be better.

"But you're not fighting Mickey Mouse or Donald Duck, you're fighting professional teams.

"We know what we are here for, we know what we want to achieve but we're not where we want to be and we're the first ones to criticise us.

"I can't give you a time or promise as in when it will be stellar as it depends on what other people are doing but I'm pretty confident we are on the right track."