Honda admits it underestimated the challenge of returning to Formula One this year, but is confident it is getting on top of its problems.
Honda joined forces with McLaren at the start of the year and has built an innovative and tightly packaged power unit under the current V6 turbo regulations. However, the Honda engine is down on power compared to its rivals and has struggled with reliability issues since its first test.
Asked if Honda underestimated the challenge of returning to F1, its chief officer of motorsport Yasuhisa Arai said: "Expectations were always going to be high because of our illustrious history with McLaren. Most of the fans have a great image of McLaren-Honda's heritage so they expected us to return to Formula One and be competitive immediately. Obviously this has not been the case.
"The sport has changed immensely since the McLaren-Honda 'glory days'. The current technology is much more sophisticated and it is tough to make a good racing car. We knew it wouldn't be easy, but perhaps we didn't imagine that it would be this hard.
"We believe that our compact power unit layout will prove to be very competitive; however we knew from the start that it would cause problems with heat rejection. We now know which area is affected, and in the second half of the season we will apply new parts to resolve the issue and apply more horsepower to improve our competitiveness.
"I certainly didn't imagine technology wise what we would be facing, but I have complete confidence in the direction we have taken with our power unit. We needed to create something radical in order to beat the top teams, and that is our ultimate goal - to beat the best."
Arai said balancing the energy recovered by the MGU-H against the efficiency of the turbo was one of the reasons the engine is down on power.
"The current regulations of the whole power unit package are very complicated so one small component triggers a domino effect of other items leading to the issues that we have been seeing.
"Let me put this concept of the domino effect into a technical example: if you try to harvest energy using the MGU-H, it puts a strenuous workload on the turbo. When the turbo is under stress, it cannot do what it is supposed to do, which is to force more air into the engine, thus leading to decreased power output. This is the result of one component working against the others, instead of working together.
"These types of technical chain reactions which lead to vehicle stoppage were definitely more than we calculated, or more than we envisioned. The difficulty with this is that you cannot calculate precisely without running the car in actual conditions, on track."