Sauber planning major car upgrade for after F1's summer break

The Swiss team is currently fifth in the constructors' championship to head the midfield pack, following Felipe Nasr's ninth place finish in the Monaco Grand Prix.

This season marks a turnaround for Sauber, which failed to score for the first time in its history last season.

"Holding on to fifth place will be difficult," team principal Monisha Kaltenborn told AUTOSPORT.

"We know other teams will do more - but we have to go our own way.

"We are working on a big update. It's not a B-spec car but a big update package.

"That will come after the break when we reach the levels we want to reach on that package.

"We will not introduce it until we can make it work, and the way things are looking, it's going to be after the break."

Nasr echoed his team boss's comments, hinting that the next few races will be tough.

"From what I hear, we're waiting on bigger updates for after the break and we might have major updates on the bodywork and bring more downforce," he said.

"I'm sure this will improve the whole package. Until then, I'm expecting to have more difficult times, where it will not been easy to get into the top 10."

Sauber introduced a new front wing three races early this year, with the team taking a couple of grands prix to make it work as it expected, and Kaltenborn envisages it will try to bring through parts of its summer package early too.

"There will be bits and pieces on the car, like we did with the front wing, where we put a few things further ahead," she said.

"We have to be flexible. When you are not in the position where you can make hard and fast plans, we take it the way it comes."