Alonso will have a new Combustion Engine and Gearbox while Button will have the New Honda Power Unit for the first time since it debuted in Alonso's car for Russain Practice.
Commonly known as 'Phase Four' of the Honda 2015 Power Unit, is meant to be worth a tenth per a lap. Button will use this engine for Friday Practice, and he will incur a further change for the race.
Written by Harry Shovelar
Bahrain International Circuit - Winter testing
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