McLaren's Eric Boullier insists that Honda must begin work on its 2018 power unit now in the aftermath of the team's disastrous opening four races.
For the sceond time in succession, a McLaren-Honda failed to even start a race. Stoffel Vandoorne sat out the Bahrain Grand Prix when his engine was diagnosed with a terminal issue while Fernando Alonso was on his way to the grid when his car simply grinded to a halt.
Boullier labeled the failures as unacceptable, and said Honda's problems are compounded by Formula 1's technological context.
"Formula one at the moment has a downside," he told Speed Week.
"The gaps between teams has increased even more.
"An engine that is more powerful is also more efficient, with better consumption and stability.
"The more powerful engines have all the advantages, and our engine combines all of the disadvantages," Boullier added.
Boullier was mum on the eventuality that Mercedes could lend a helping hand to Honda, as suggested at F1's Strategy Group meeting last week in Paris.
But the Frenchman was adamant that its engine partner must now initiate work on its 2018 engine.
"2017 is still under development," he said, "and the rest is the responsibility of Honda.
"But Honda must start now. Mercedes, for example, already has an engine that will run in 2018."
Gallery: All the action from Sunday in Sochi
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