Jenson Button says that there was nothing unsettling about the performance of the McLaren MP4-29 on its first day of running at Jerez.
Button missed the opening day of testing on Tuesday due to an issue with his car but was able to complete 43 laps on Wednesday, setting the fastest time of the test.
"For our first day of actual running, we were able to get a good understanding of the car, and the way the engine and turbo behaves," he said. "It’s tricky, and very different to what we’re used to, but I could feel that these cars will be enjoyable to drive.
"Of course, it’s still early days, and there’s a lot of work ahead of us. We need to work on both braking and traction; but that excites me, because there’s a lot of potential to adjust those parameters. The new braking system is very complicated, and getting it right will be tough."
"But these are all things we can work on: there’s nothing about the car that unsettles me, and there’s plenty of scope to explore the set-up. It will just take time."
"Our main aim this winter was to field a reliable car that would give us a good baseline. These cars will develop so much over the next few months, so it’s essential to have a solid base to build upon; and I think we have that good base."
Button was due to hand over duties to team-mate Kevin Magnussen on Thursday but the Brit will remain in the car during the morning session.