Renault test driver Esteban Ocon heaped praise on the manufacturer's upgraded power unit after it made its debut during in-season testing at the Circuit de Barcelona-Catalunya.
Ocon only amassed six laps in the older version of the power unit during Friday's practice session in Spain but wwas able to note the progress after completing 105 laps on Tuesday.
Renault intends to bring the B-specification to make its race debut at the Canadian Grand Prix.
"You’ll be surprised, it’s really good, really good," he said.
"I can tell it will be quicker for sure.
"For sure you don’t push it 100% in the test, but overall the reliability was good, we didn't have any problems, we did 105 laps so it’s a really good debut and really good start.
"It’s good to finally be running with decent mileage, important for me and the team to get a lot of laps, no major issues, made up a lot of laps and lots of testing, important for the future of the season."
Ocon also confirmed that he is set to receive several more outings for Renault during Friday practice sessions at Grands Prix.
The Frenchman will be back in action on Wednesday as he is set to make his debut for Mercedes.