After confirming its intention last year to return to Formula One in 2015 not with its own team but as an engine supplier to McLaren (perhaps with more team agreements to come), Honda has now revealed its engine for the new season. Officially labeled a power unit, since the ‘engines’ in F1 now comprise an internal combustion unit and an energy recovery system with two electric motor/generators, the unit will now be put through a rigorous testing phase.

Honda is still developing its power unit at its main R&D center in Tochigi, Japan and plans to show it off at this weekend’s 2014 Japanese Grand Prix. In addition to conducting simulations, Honda has moved onto the next stage where it will conduct full-fledged bench tests of the unit while connecting the internal combustion unit, a turbocharged 1.6-liter V-6, with the energy recovery system.

In the meantime, Honda’s F1 base in Milton Keynes, U.K., has become fully operational. The new facility will serve as the frontline for Honda’s F1 operations and will be responsible for maintenance of the new power units delivered to teams.

Current power units in F1, built by Ferrari, Mercedes AMG and Renault, develop upwards of 750 horsepower. The internal combustion unit alone develops around 600 horsepower and is aided by the two electric motor/generators: one adding a maximum 161 hp and the second helping spool up the turbo. When not needed for power, these motors recover energy (from exhaust heat and braking) which is then saved in a battery.

Honda has been in F1 several times in the past. The Japanese automaker first entered the sport in 1964 but then withdrew following the death of driver Jo Schlesser in the 1968 season. Honda later returned as an engine supplier, with its units of the‘80s and early ‘90s considered some of the most powerful and reliable in F1—they helped secure numerous wins for the likes of Ayrton Senna and Nelson Piquet. Honda had its own team again in 2006 but with limited success and the global financial crisis hitting soon after the debut the automaker pulled out again at the end of the 2008 season.