Nico Rosberg sounded positive on the first day of testing in Barcelona after topping the timesheet come the end of the session.
The German declared the W04 “a lot faster” than last year’s W03 which won the Chinese Grand Prix, but failed to challenge for podiums and even points as the season progressed.
His 1:22.616 was just seven thousandths quicker than Kimi Raikkonen’s best lap in the Lotus, but Rosberg believes they have a much better base to work on compared to last year.
“The car feels decent out there,” he said. That’s a good start.
“It’s a much, much better base. You can feel its centre of gravity is lower. The aero is better. The platform is better.
“It feels a lot stronger. It’s a pleasure to drive because it’s a lot faster than last year.”
His only concern surrounds reliability after he managed just 54 laps on Tuesday and struggled for mileage at the first test in Jerez.
“I didn’t get many laps in,” he added. “That’s a bit of a pity, for sure. We have to work on that.
“We have a few too many reliability issues at the moment. Other than that, it’s definitely going in the right direction.”