Honda has fixed the recovered energy deployment problems that severely compromised McLaren's 2015 Formula 1 form, according to the team's racing director Eric Boullier.
McLaren struggled in many of last year's grands prix thanks to a lack of straightline speed, which the team attributed to inefficiencies in Honda's Energy Recovery Systems.
Honda has redesigned the compressor and turbine on its 2016 V6 turbo hybrid engine, and Boullier reckons rivals will no longer have a substantial advantage in this area.
"The good news on the PU side this year is that there has been a fix for this issue," Boullier said.
"There will be some tracks where we can't deploy it totally, but this is the same for everybody I think.
"I believe there is one [rival] who will still have a little bit more advantage this year, because they have developed this part too, but at least we will be as good as the others last year."
Boullier said Honda has made "clearly a gain" in terms of outright performance with its new power unit.
Although McLaren has had to modify bodywork to accommodate the new specification, he said so far it had introduced no major new reliability problems.
Honda's progress has also impressed double F1 world champion Fernando Alonso, according to Boullier.
"The comparison was straightforward and he was clearly happier," Boullier added.
"I think he will also be happier tomorrow, because we have been doing some mapping work since Tuesday and the engine is better."
Alonso said during last week's Barcelona test that he felt McLaren could develop the MP4-31 into the best chassis on the grid by the start of the European part of the new season, and Boullier confirmed Alonso's hopes were realistic.
"Yes it is," he said, in response to a direct question about Alonso's comments.
"This is obviously what we work for at McLaren, to have the best chassis.
"We're happy if we can achieve this; it means McLaren is back on track."
Boullier also reiterated that McLaren has not compromised its 'size zero' aerodynamic philosophy to accommodate Honda's engine revisions, despite the bodywork changes on the car.
"The size zero philosophy doesn't [disappear] with this kind of change," Boullier said.
"Honda is free to do what they want to make the engine the best. We can always accommodate."
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