Honda will run their upgraded power unit at this weekend's Belgian Grand Prix, with both McLaren's Fernando Alonso and Jenson Button getting a new unit each.
Honda have been working hard over the summer to continue its engine development programme in the hope of delivering further upgrades before the final race of the season.
The Japanese manufacturer recently confirmed it would likely bring two final upgrades this year before focusing on 2016.
Prior to this weekend, Honda had ten development tokens remaining. It's believed they have spent seven on this latest package which is a substantial upgrade to the combustion chamber, turbo and compressor.
The new unit is expected to deliver an overall horsepower increase as well as greater efficiency, though Honda haven't given a predicted lap time improvement.
Both McLaren drivers will run the engines during free practice on Friday before Honda and the team take a final decision on whether to continue using them for Sunday's race.
The engine will be Alonso's fifth complete unit, whilst Button will be on his ICE, turbo, MGU-K and MGU-H.
