Fuel Consumption in a Fully Loaded Land Cruiser 120 D4D – Real Travel Data

Our Land Cruiser 120 D4D is equipped with a 3-liter turbocharged diesel engine with an intercooler. It runs on diesel fuel. The car meets the EURO 4 emissions standard, which means we are allowed to enter so-called "Environmental Zones" in Europe. To do this safely and without issues, it's worth placing a green "Grüne Plakette" sticker on the windshield - available for a small fee based on a vehicle inspection or VIN check.

Before we started modifying the vehicle for travel, it consumed around 8–9 liters per 100 km on highways at speeds not exceeding 120 km/h. The LC120 has a large frontal area, meaning air resistance is the biggest factor influencing its fuel consumption.

·        Elements that additionally increased fuel consumption:

·        permanent roof rack

·        accessories mounted on the roof rack (tent, transport box)

·        bicycles

·        AT (All-Terrain) tires

·        the overall weight of all the gear we carry on trips

Our typical highway cruising speed is 100–120 km/h, and once we leave highways, we rarely exceed 50 km/h.

**How do we measure fuel consumption?** The onboard computer shows an approximate average, but it’s not highly accurate. To estimate fuel consumption over a recent journey (e.g., 500 km), we fill the tank completely, drive 500 km, then refill it fully and calculate consumption manually. Simple formula: (liters used × 100) ÷ kilometers driven Example: After driving 500 km, I filled up with 48 liters of diesel.48 × 100 = 4800, and 4800 ÷ 500 = 9.6 liters per 100 km.

Trip Consumption Examples

Portugal trip (over 8,000 km): average 11 liters/100 km. Norway trip (mountainous terrain, fewer kilometers): average 12.5 liters/100 km.

Fuel Consumption by Configuration

Configuration	Average Consumption (liters/100 km)
Stock vehicle (before modifications)	8–9
Summer tires + roof platform (no tent)	9–10
Summer tires + roof platform + AT tires	10–11
Summer tires + roof platform + AT tires + rooftop tent	11–12
Full expedition setup (Portugal trip)	~11
Full expedition setup (Norway trip, mountainous)	~12.5
Full expedition setup (Greece trip)	~12

Fuel-Efficient Driving

Find your own safe cruising speed - the speed you maintain on highways and major roads. We recommend trying a few longer drives (about 200 km each) at different speeds: 90, 100, 110, and 120 km/h - then assess fuel consumption, handling, and your feeling of safety. Speed off highways: For us, it's always about traveling slowly enough to enjoy the journey, not rushing.

Does Driving Faster Really Save Time?

When planning long journeys, it’s tempting to think that driving faster will get us to our destination much quicker. In practice, the time savings are often smaller than we expect while fuel consumption increases sharply.

The table below shows how different cruising speeds affect both travel time and total fuel used over an 800 km distance. It clearly illustrates that while speeding up from 90 km/h to 120 km/h saves a little over 2 hours, it also increases fuel usage by nearly one-third. At 140 km/h, the time savings become even smaller, while fuel consumption continues to rise significantly.

In real-world conditions, especially with a heavy, expedition-ready vehicle - driving moderately fast often strikes the best balance between safety, comfort, fuel efficiency, and arrival time.

Speed (km/h)	Fuel Consumption (l/100km)	Time to Cover 800 km (hours)	Total Fuel Used (liters)
90.0	9.5	8:53	76.0
120.0	12.5	6:40	100.0
140.0	14.0	5:43	112.0

Running Out of Fuel?

In diesel vehicles, running out of fuel can mean air entering the system or contaminating it - causing serious problems. We avoid running the tank completely empty. When reaching ¼ (about 20l left) tank, we start looking for a gas station. The LC120 has an 87-liter tank. We usually refuel when there’s about 20 liters left. We also carry an additional 10-liter jerry can, although we have not needed it yet.

Test Your Cruising Speed We find it useful to occasionally check our real-world consumption at different speeds. Here's a simple template you can use if you want to test your own vehicle and driving style.

Tested Speed (km/h)	Average Consumption (liters/100 km)	Driving Impressions (comfort, stability, safety)
90 km/h
100 km/h
110 km/h
120 km/h

Try to drive around 200 km at each speed, then fill up and calculate average fuel consumption. Compare not only numbers but also how you feel behind the wheel - remember, safety and comfort matter more than reaching your destination quickly.

Quick Summary – What Matters Most

• Know your cruising speed: Choose a safe and comfortable highway speed. Heavier vehicles, rooftop gear, and longer braking distances all demand more caution.

• Respect air resistance: Speed increases air drag exponentially - driving faster dramatically raises fuel consumption.

• Keep a fuel reserve: Never run the tank empty. Start looking for a gas station when reaching ¼ tank, and always carry a small fuel canister just in case.

• Prepare for remote areas: If you plan to travel into remote, off-road, or sparsely populated regions, research fuel station availability in advance and significantly increase the amount of backup fuel you carry.

• Measure, don’t guess: Calculate real-world fuel consumption manually over longer trips. Onboard computers can be optimistic.

• Think ahead: Extra weight, roof-mounted gear, and tire choice all affect fuel use and vehicle stability. Plan your setup wisely for your destination and conditions.

In the end, safe driving and smart planning are worth far more than a few minutes saved on the road.