Carlos Sainz Jr. says Renault has lost out in the engine development battle, and that Honda’s recent one-lap progress is “a worry”.
Renault has scored just 10 points since the summer break and is under renewed pressure in the standings from Haas, while customer McLaren has also struggled for pace.
Renault has lagged behind Mercedes and Ferrari in the engine race while Honda introduced its Spec 3 package in Japan, helping both Toro Rosso drivers to make Q3.
“We have taken the biggest hit from the engine side,” said Sainz Jr.
“We thought by Canada when we were clearly leading the midfield, that the B spec had been successful, which it was at the time.
“Up until Hockenheim we were happy enough with what we had. We thought we were going to make it to the end of the year being a Q3 team and scoring points.
“But then there were the upgrades that Mercedes and Ferrari brought to Austria and Hockenheim and Hungary, and we started to feel them a lot in places like Spa, Monza and Suzuka.
“To compensate for that big engine deficit, we should have brought more aero than what we got, but it is mainly dominated by engine.
“I managed to overtake both Honda car in the race at Suzuka with better race pace than them, which was a good boost for us.
“But in qualifying they took a step that for us starts to be a worry. They took a step in qualifying and that puts them in Q3.”
Sainz Jr. will switch to the Renault-powered McLaren squad for 2019 and expressed confidence that the manufacturer can provide an engine “at the level of Ferrari and Mercedes”.
“I am always optimistic at this time,” he said. “I can also see people inside Renault, inside Viry, so at this time of the year we are optimistic.
“In winter testing maybe my face changes, but up until then I am going to be optimistic and think that Renault are finally going to deliver an engine that is clearly at the level of Ferrari and Mercedes.
“From what I heard it [the engine] is still going to deliver a step that Renault and McLaren need next year.
“And thanks to that, hopefully we should be closer in top speeds to our competitors and we shouldn’t start compromising the rear wing for these kinds of tracks.
“And thanks to that we should start really start to fight the Mercedes and Ferrari cars also on the straights, not only in the corners.”
