At CAR, we take each vehicle we test on a standard fuel route of 100 km (comprising urban and motorway sections) to gather data on its "real-world" fuel consumption. Listed below are the five least fuel-efficient cars (measured in litres per 100 km) we tested in 2018 ... bar the McLaren 720S*.

5. Haval H9 2,0T AWD Luxury: 12,60 L/100 km (claimed: 10,90 L/100 km)

Despite being the second heaviest car on this list (weighing 2 391 kg, according to our scales), the H9 is equipped with the smallest engine here. The Chinese marque's largest offering is powered by a 2,0-litre petrol four-pot producing 180 kW and 350 N.m of torque. And it's not exactly light on fuel...

4. Nissan 370Z: 13,30 L/100 km (claimed: 10,5 L/100 km)

The Nissan 370Z may be a decade old but the naturally aspirated Japanese sportscar, especially in manual guise, still offers plenty of thrills. The naturally aspirated 3,7-litre V6 (producing 245 kW and 363 N.m) is heavy on juice, though...

3. Mercedes-AMG C63 S Coupé: 14,60 L/100 km (claimed: 8,91 L/100 km)

Mercedes-AMG's midsize muscle car does have its shortcomings, with fuel consumption being one. However, compared with its six-cylinder German rivals, the C63 S coupé's 4,0-litre V8 possesses tonnes of character.

2. Nissan Patrol 5,6 V8 LE Premium: 15,10 L/100 km (claimed: 14,40 L/100 km)

Nissan Patrol

The seventh-generation of the Japanese SUV is equipped exclusively with a naturally aspirated 5,6-litre V8 gas-guzzling petrol engine churning out 298 kW and 560 N.m of torque. We can't say we're surprised it's on this list...

1. Mercedes-AMG GT R Coupé: 18,00 L/100 km (claimed: 11,40 L/100 km)

720S

What's under the Mercedes-AMG GT R's bonnet? Eight cylinders, neatly organised in a "V", producing some 430 kW and 700 N.m. There's no denying this 4,0-litre twin-turbo sportscar supplies aural drama to both its occupants and onlookers. But, with a recorded 18,00 L/100 km on our combined fuel route, turns out it's quite an expensive soundtrack...

*Note: since we had the McLaren 720S (tested in the June 2018 issue) for a very short period, we weren't able to put it to the test on our fuel route.