Nick Heidfeld says Renault's Spa update must work if it is to save its season

Renault failed to build on a strong start to the year that included podiums in Australian and Malaysia, with matters not helped by a lack of early year development progress in the wind tunnel and a mid-season shut down of the facility to upgrade it.

However, the team has unlocked some good improvements at the factory and a lot of the new parts - including wings, bodywork and floor updates - will come on tap for the next race at Spa-Francorchamps.

Heidfeld believes that, on the back of recent struggles, it is essential these updates do bring what is promised, as the outfit bids to try and retake Mercedes GP for fourth in the constructors' championship.

"If it doesn't work, then we are in trouble," Heidfeld told AUTOSPORT about the major update package coming for Belgium. "Let's hope for the best.

"I feel it finally has to work because we have been saying for some races now that we understand the problem, and that we have moved forward. This will be the first time that we really have something big.

"Since we found out our problems we have made some small things. But we have made some big improvements in the wind tunnel now, and it was not that easy to bring all the parts to the circuit yet. So Spa is a very important place for us to go in the right direction."

Renault may continue to experiment with a rearward facing exhaust system in Belgium, but it is undecided about its plan just yet because the big updates coming are built around the forward facing concept.