Red Bull have built their own F1 engine for the first time this year, in partnership with Ford
There were two key talking points at the first of two pre-season tests in Bahrain - whether the new cars were still "Formula 1", and the performance of the new Red Bull engine.
Four-time champion Max Verstappen said the revised cars and engines had turned the highest level of motorsport into an exercise in "management".
"As a pure driver, I enjoy driving flat out," Verstappen said. "And at the moment, you cannot drive like that. A lot of what you do as a driver, in terms of inputs, has a massive effect on the energy side of things. For me, that's just not Formula 1."
The reigning world champion Lando Norris did not agree, saying the new cars were "a lot of fun" and pointing out that Verstappen was welcome to race somewhere else if he didn't like it.
