In May 2013, Honda announced its return to the FIA F1 World Championship in 2015 in an agreement to supply F1 power units to McLaren, marking the return of McLaren Honda after a seven-year hiatus since its withdrawal at the end of 2008. This was to be the return of the invincible McLaren Honda.

Starting in 2014, F1 engine regulations had shifted to a hybrid system that actively utilizes motor power using an MGU-H, which generates electricity using the turbocharger’s shaft rotation, alongside a 1.6-liter turbocharged V6 internal combustion engine and MGU-K. Honda’s return to F1 was a challenge for the new high output and complex hybrid era.

Honda, which had been considering a return to F1 since 2012, had nearly no experience with the new power unit’s complex systems, and the development period of less than two years was far too short. The challenge was further complicated with McLaren’s demand of an ultra-compact power unit, and Honda entered its first year back in F1 under less than perfect conditions, including the engine’s durability and reliability.

The MP4-30, newly designed under the “Size Zero” concept to accommodate Honda’s power unit, was innovative, with bodywork behind the cockpit as slim as possible to allow clean air to flow to the rear, enhancing aerodynamics. Yet, many aspects of the design that had been attempted with the previous year’s MP4-29 were not implemented, opting for a more orthodox design. For example, the MP4-29’s intercooler was on the left side pontoon and the water radiator and engine oil cooler were on the right, and the cooling surface faced the sides for aerodynamic efficiency. The MP4-30, however, has slimmed down the heat exchanger and tilted it forward to return to a more conventional layout. This was typical of McLaren, which has abundant resources and could repeatedly try and refine its methods.

McLaren's unique approach was also apparent with the many updates and modifications that were made during the season. At the beginning of the season, the front section was introduced with a long nose to meet the new regulations, but was modified during the season, and by mid-season was shortened. Many track-specific front wing designs were also used to increase competitiveness.

The much-anticipated revival of McLaren Honda was shrouded in uncertainty from the pre-season tests. Development stalled as problems continued to plague the team and few laps were run. On the final day of testing, Fernando Alonso went off-track and crashed, injuring himself, and missed the opening race of the season. In the opening round, the Australian Grand Prix, Kevin Magnussen, who filled in for Alonso, was unable to start the race as white smoke came from his car on the way to the grid, and the team was instantly enveloped in a gloomy mood. Despite this, Jenson Button’s 11th place finish was a ray of hope for the team, as he drove like a true seasoned driver in the midst of the chaos.

The team’s first win came in Round 6, Monaco. Button, starting from 10th, drove a solid race to finish in 8th place and score his first points of the season. However, subsequent problems and the need to reduce output created a vicious cycle, and the team was unable to achieve satisfactory results in either qualifying nor the race. In qualifying, McLaren Honda failed to advance to Q3 even once, and their best finish was Alonso’s 5th in Round 10, Hungary. In addition, regulations limiting the use of power units to four per year resulted in both Alonso and Button, who used a total of 12, being hit with grid penalties, compounding their difficulties in gaining decent results.