I’ve always taken peoples fuel economy results with a grain of salt. Call me a sceptic, but I’ve seen too many people not working it out accurately to believe what I’m told without seeing it take place.
There are so many variables that go into 4WD fuel economy, and often its not worked out properly due to bigger tyres putting speedometers out, people calculating it ‘by the tank’ and trying to come up with the best economy purely for bragging rights.
In this post, I will share with you the correct fuel economy figures that we have had from our Isuzu Dmax, all speedo corrected and done to the second decimal point when filling up with fuel. You’ll see it varies a lot, depending on what we are doing, and it has gotten considerably worse as the vehicle had more mods done to it.
When we first got the Dmax, I was comfortably doing 8.5 – 9.0L per 100km. That’s the factory tyres, no lift, nothing in the rear and just a factory bull bar. Fairly impressive. Even with some 4WDing involved, it would rarely creep over 10L/100km. From the factory, the Dmax speedometer is out by about 7%, and the odometer is correct.
However, since then, I’ve fitted 54mm bigger tyres (7.2% bigger), a big canopy, different bull bar, big light bar up high, a lot of extra weight and the vehicle has been lifted 30mm.
All of these things have played a fairly substantial increase in making the vehicles fuel economy worse. Around town, it generally sits at 10.5L/100km. Throw a bit of highway driving in without towing and you’ll get a minor increase, but not much.
Over 3 months up north, and 16,000km, our Dmax averaged 13.8L/100km. A large majority of those kilometres were on bitumen, towing a 1300kg camper trailer at 100km/h. Maybe 1/3 of the driving was done without towing anything, and usually 110km/h, with the occasional run at 130 in the Northern Territory (but the Dmax isn’t a fan of that speed!).
We did about 400km around Kununurra not towing, with maybe 100km of slower 4WD tracks, and averaged 10.5L/100km. Not bad!
The Dmax will absolutely suck the diesel when it has to work really hard though, like many vehicles do. When towing into a head wind, we saw fuel economy figures of around the 18 – 19L/100km – roughly 2.5 x the factory fuel economy figures!
Our 4.2 turbo diesel 80 series averaged 16.9L/100km over nearly 10,000km from Perth to the Kimberley. It was heavy, big and we sat on 110km/h where possible. The fuel economy when 4WDing would shoot up though, and with all of the gear on it we never got better than 14.5L/100km. I did have it up around the 35L/100km on a couple of occasions in soft sand!
Today, we use the Isuzu Dmax to tow a Lifestyle Reconn R2 hybrid camper, which probably weighs in at around 2.2 tonnes when fully loaded. It seems to sit at around 13 – 15L/100km depending on the temperature and how hard we are working it.
We have managed to get under 13L/100km doing 100km/h and towing the camper, which is an exceptional result. Fully loaded, we come in around 5.4 tonnes. We had a mobile weighing service come and look at everything, which was quite fascinating. You can read more about this here – mobile weighing.
Overall, we are pretty happy with the Dmax fuel economy. It now has a long range tank, and we can get over 800km in between refills, which is more than enough for touring this amazing country. Prior to the long range tank we were stopping every 400 odd kilometres, which was a right pain in the backside.
What fuel economy does your 4WD get? Are you happy with it?