Red Bull needs more from Renault's Q3 engine mode, says Horner

After a tricky start to the season, which included windtunnel correlation problems, Red Bull has made good gains with its chassis and Renault has been pleased that improved reliability has allowed it to push components harder.

Red Bull scored one podium in the first four races, then went on a run of five-consecutive rostrums - including victory in Azerbaijan - with Daniel Ricciardo.

Although its race pace now appears to be as strong as F1's pace-setters, Horner says it is compromised by it starting too far back, a consequence of Q3 engine modes that Mercedes and Ferrari drivers are able to employ.

He suggested that Red Bull would be more of a factor "if we can just find that little bit more performance" from the engine.

"The car is getting stronger and stronger under race conditions, and again it was a very competitive grand prix for us in Hungary," said Horner, when asked about the role of Renault in his team's hopes for the rest of the year.

"You saw in qualifying that Max [Verstappen] was second quickest in Q1 and Q2, but you get to the latter part of qualifying and you need that little bit extra to go with our major competitors."

Pushed on whether it was realistic to expect big engine changes this year, with Renault's main focus on taking a bigger step with its 2018 engine, Horner said: "I think you need to speak to our engine supplier to understand what their thoughts are regarding engine introduction."

The engine situation has left Horner sceptical about chances for races coming up next, only saying he hopes Red Bull can be "reasonable" in the Belgian Grand Prix that kicks off the second part of the season.

"On Saturday we are going to struggle," he said. "I can imagine us being fifth and sixth on the grid on Saturday and quicker than that on Sunday.

"The thing I can say about Spa is that you have the ability to overtake there."