Ferrari used three of its engine token allocation to introduce its first big update of the season at the last race in Canada, but Sauber did not run the new package.

With drivers restricted to four engines per season, Sauber team boss Monisha Kaltenborn said it made sense to wait until Spa, a track where the update will have the most effect and by which time further developments will have been added.

“We have been told Ferrari is still doing development, so from that perspective, we expect a bigger upgrade in the engine after the summer break,” said Kaltenborn.

“If it happens like this, it will come at a time when we hope to introduce a big update package for our car.

“Spa is a race where the engine update will really matter. The next ones coming we are alright.

“But Spa and Monza are the ones where you can really feel the upgrade.”

Kaltenborn denied the decision had anything to do with finances, adding that Ferrari had been keen for the team to run the update sooner.

“It did not have anything to do with finances,” she said.

“The driving force is definitely coming from our engine supplier.

“But you have to look at your own strategy and see what you are most comfortable with.

“We are on our second engine [of four] and they [Ferrari] are getting in the third engine so obviously they have a different strategy.

“If you need to return to an old engine it’s a different approach to things.”