Generally I average 14.5l/100k towing, that equates to approximatly a 400k range from a 63l fuel tank, basically it mean if I tried to get 400k from a tank in good conditions I would only have 5l left in the tank thats not a very good safety margin, so I added a 55l drop in tank into the tub of the ute, it gravity feeds in to the main tank via the tank breather. So that extenda the range to about 800k towing.

https://boaboffroad.com.au/product/50-litre-rectangular-poly-diesel-tank/

Kevin,
We get from 12-17L/100kms depending on wind conditions (commonly around 13-14) sitting on 95-100kph with 2 ton following behind us.

Without the van & a mixture of town, country driving - 8-10L/100kms.

2019 Isuzu D-Max with canopy.

The previous Navara I owned had a 65 litre supplementary tank. It gave me a safe 800 km towing range. I often got 1,200 km out of it when at home.

The longest we have done is Norseman to Penong including some small side trips, about 1200km. 70L plus 50L petrol on the roof. We would have made it to Ceduna. Not towing.

Filled up in Esperance as it is cheaper, topped up at Norseman. We usually use 98 as the extra cost is recovered in the additional milage.

oldbloke wrote:

---

2014 Triton towing 2.5t 20" van 15 to 17 ltr/100km @ 85kph. Seems to vary a bit on road condition. Rough roads eat more fuel, as does speed.

---

Its been my experience oldbloke that even a good gravel road will soak up 5-10% more fuel.