Eric Boullier believes McLaren can be competitive this year but is targeting the end of next season to get back to full strength.
McLaren joined forces with Honda at the start of this year but has yet to score a point in the opening four races of the new partnership. The car's performance has improved since the start of the season, but Boullier says Honda is still catching up on the development time it has lost to its rivals.
"We can become competitive this year," he told the New York Times. "We will be regularly competitive next year. I think that before the end of next year, we will be there.
"It's the year and a half that we missed, to catch up. We are building up everything in strength. But the project is extremely ambitious.
"Honda has the commitment to get back, and we - Ron [Dennis] and the McLaren stakeholders - are all putting everything in place to become a competitive team. So that will come. But we just have to catch up, and we need just a little bit of time."
Boullier is confident McLaren's difficulties will not trigger the gradual decline of the brand.
"I know what is happening behind the scenes. Already, as I said, the car itself is not yet a winning car, but it soon will be. Our engine partner will also gain in maturity, and we know we will grow in strength. McLaren is back, no worries.
"The other thing is that McLaren is part of a McLaren Technology Group, where we have a few businesses, like McLaren Applied Technologies, that are working well.
"The series of F1 is driving the brand, and the technology that we're selling and that we're developing around F1 is consolidating a huge business. We're already nearly a billion-dollar-turnover business - not F1, but McLaren. The F1 team needs to stay just F1: back to racing basics."