Ferrari's 2016-spec engine customers have given the thumbs up to the new power unit specification released by the Maranello marque for Spain.
The works team debuted the update in Russia, but it is now up and running at customer teams Sauber and Haas as well.
"It's a track on which we have a good reference," Sauber's Felipe Nasr, referring to Barcelona, told UOL.
"The improvement in the engine is noticeable, although it's a small step focused mostly on energy recovery. But it's better than nothing."
Indeed, the engine is struggling Sauber's only upgrade this weekend.
As for the new American team Haas, drivers Romain Grosjean and Esteban Gutierrez are struggling with the car but happy with the engine update.
"The drivers are very happy with it," team boss Gunther Steiner is quoted as saying by Auto Motor und Sport.
"It is a small development step but performance, driveability and energy management are all better."
Mercedes driver Lewis Hamilton will take pole position when the Spanish Grand Prix gets underway tomorrow.
