The contest kicked off last week with the Spanish Grand Prix, and sees the team's 17 truck drivers competing for maximum points, as they drive the trucks for the European leg of the season, culminating in the Italian Grand Prix in September.
This is the third time the contest has been held: this year, for the first time, it will also measure braking as a percentage of the journey distance.
Drivers are also measured on factors such as levels of throttle pressure, idling, coasting and engine operation.
The team's truck fleet uses Mobil Delvac 1 LE 5W-30 heavy-duty diesel engine oil and Mobilube 1 SHC 75W-90 gear and rear axle oil.
"Formula 1 is a contest that hinges not just on raw power and speed, but also efficiency," says Eric Boullier, racing director for McLaren-Honda.
"We compete to cover the distance in the shortest possible time and the most aerodynamic car with the most efficient engine has the best chance of getting there first. Efficiency is part of McLaren's DNA and ExxonMobil has consistently innovated to help us do more with less."