Ferrari explains its decision not to take new F1 engine in Belgium

While customer teams Haas and Alfa Romeo have debuted the third power unit of the year in Belgium this weekend, Ferrari has decided to wait for the Italian Grand Prix.

Speaking at Spa on Saturday, Ferrari's sporting director Laurent Mekies explained that the power sensitivity of Monza played a part in its decision.

"It is the highest power effect of the year... What that means is you gain 10bhp on your engines and that is two tenths in your pocket," said Mekies.

"A lot of people, including ourselves, use it [Monza] to bring their third and last power unit, although you may have seen a lot of our competitors have done that here.

"But there is a reason [why Ferrari has waited] - the engine's performance may drop with mileage, so you want the freshest engine with the higher power effect of the year."

Ferrari team principal Mattia Binotto said giving Haas and Alfa Romeo the first running of the new power unit in Belgium was not about getting extra data on the engines to detect any potential problems.

Asked by Autosport how useful having the customers running the new engine early was, Binotto said: "It is not useful.

"The reason is not to get real data, because by the time you introduce a unit it should be reliable, fully reliable and homologated and validated on the dyno.

"The reason we are introducing it is because we are on different scenarios in terms of allocations and in terms of mileage, and certainly by splitting the building of the engines it makes it a lot easier at the factory."