McLaren’s racing director Eric Boullier says the team’s real 2018 car won’t be seen until next month’s Spanish Grand Prix.
McLaren had issues with reliability during pre-season testing, which forced the team to alter its upgrade schedule.
Boullier described the current car used this season as an evolution of last year’s Honda-powered design.
"The 2018 car is coming to Barcelona, and obviously we hope that's the car we expect it to be,” Boullier said.
"The car we have now, is as per plan, it's not that we missed the targets with it.
"But we missed the schedule targets with it, which means the car we'll have in Barcelona should have been in Australia.
"So we are running actually with an evolution of last year, and not the new car. And this car hopefully will be the one that we expect.”
The Renault powered MCL33 has proved strong in races, but has lacked qualifying pace, and Boullier has admitted the opening races have been frustrating, saying:
"So far we have been opportunistic, and we took the opportunities we've had with both drivers to take as many points as we could.
"It's just frustrating to see that we have such performance or pace in the race, and we are unable to unlock yet that performance in qualifying.”
With the lack of qualifying speed, a McLaren have yet to make it to Q3 in 2018, but has scored points in all three races, leaving the team fourth in the constructors’ championship.