Honda F1 technical director Toyoharu Tanabe says a better understanding of the manufacturer's 2021 power unit has led to performance gains, denying rumors of a specification change.
Honda has powered Red Bull Racing to five wins this season, including in the last four races. But the introduction of fresh units in France for Red Bull's teams and the subsequent performance led to suggestions, fueled mainly by Mercedes, that Honda had upgraded its engine.
But Tanabe reminded Honda's rivals that "under current regulations any performance update is not allowed during the season.
"As a result, our PU is the same as the first PU, in terms of specification and performance."
Mercedes boss Toto Wolff later walked back his "update" claims insisting he had been misinterpreted, while Tanabe revealed that any gains achieved by Honda this season had been the result of its engineers improving their understanding of the new unit.
"We started to use this new 2021 PU from the pre-season test, and we have been learning gradually how to use our PU," he said.
"And we improve our weakness, and we push our strengths, and as a result the pace. The specification on the performance is the same but trackside performance I believe we have been improving."
Despite Red Bull's recent string of wins, Tanabe-san does not believe that the Honda engine is now the class of the field in F1.
"We keep analysing our position compared to the other PU manufacturers," he said.
"[In the] analysis, we include the chassis performance as well, because [with] a good car with less downforce sometimes you see a good engine power performance, so it’s a little bit difficult to judge.
"Our current result gives us [the conclusion that] still we are not number one.
"But as I said we cannot improve the pure performance, like ICE performance, then we are working very hard how to use the PU efficiently at the track, so we want to use current hardware more efficient [together] with the team engineers."
Regarding 2022 and Red Bull taking over Honda's engine program, Tanabe revealed in Austria that Honda's engine facility in Sakura will continue to assemble the units next season.
"Yes, Red Bull and Honda have been working on that project, and then how to proceed in that transition for next year," said Tanabe.
"I cannot tell the detail, but generally we are going to a good direction and then we should prepare well for next year. So now we are working very hard, I am working very hard at the trackside."