Updated: Mar 21, 2021
Long range fuel tanks are one of the best bang-for-your-buck modifications available for the outback tourer.
Fuel range is probably the defining requirement of Australian overland touring. Even relatively simple trips like the Birdsville Track or Cape York can test the factory fuel capacity of some vehicles, and if you're looking at the Simpson Desert or Anne Beadell Highway, most vehicles will need to start thinking about carrying extra fuel.
Serious remote area expeditions like the Talawana Track, Canning Stock Route or Madigan Line, need to incorporate fuel carriage into the way the vehicle is prepared and built.
The traditional way to carry extra fuel was with jerry cans on the roof rack, but this is a dumb place to carry so much weight, and you have to carry the empty containers for your whole trip even if you'll only need them on one leg of it.
How to carry fuel like a dumbass - read more:
Obviously the best place to store fuel is where the manufacturer intended - underneath the vehicle. A quality long range tank costs less than a set of tyres and makes a huge difference to how you plan, pack, and drive your next remote adventure. It's a no-brainer.
Long Ranger 180L auxiliary tank
The Long Ranger (not to be confused with Long Range Automotive) are an established manufacturer of long range auxiliary and replacement tanks, located only a short drive from my home. They build from aluminised steel and offer several options for the 200 Series, which are designed to replace the original Toyota 45 litre sub tank above the spare wheel. Options include a 70 litre tank that retains the spare wheel, 90 and 180 litre tanks which delete the spare wheel, and a hybrid 122 litre fuel tank/55 litre water tank which also deletes the spare wheel.
I chose the largest option, the 180 litre replacement. Combined with the original Toyota 93 litre main tank, that gives me 273 litres (72 US gallons) of capacity. This still isn't enough for all of my trips, but depending on my actual fuel consumption in real conditions, I don't imagine I'll ever need more than another two or three jerry cans. It's a lot easier to find space for three jerry cans than for ten - I already have two carriers built into my camper trailer, so I only need to find space for one more.
How the two tanks work
Three of my previous vehicles have had long range tanks fitted and there are differences in how these systems work.
My GQ and GU Patrols had a main tank and an auxiliary tank (the GU came with this from the factory; the GQ was another Long Ranger product). They both had their own filler neck, their own gauge, and a transfer pump activated by a dash switch. When the main tank got down to about one quarter, you'd flick the switch and fuel would transfer from the aux into the main, where the factory fuel pump would send it to the engine.
My Navara had a simple replacement tank, which swapped the Nissan 70 litre job for a huge 160 litre one. This retained all of the OEM pumps, fillers, gauges and senders so there was nothing to see or press inside the cabin. Because the original tank sender unit wasn't calibrated for the larger tank, the dash gauge would read full until I'd used about half the new tank, and then fall from there.
The 200 Series is a bit... unique. The guys at Long Ranger explain it quite well here. The factory arrangement uses a 93 litre main tank and a 45 litre auxiliary. The two tanks share a single filler which splits incoming fuel between the two tanks. The engine lifts fuel from the main tank using a tank-mounted electric fuel pump. There is also a venturi jet pump in the main tank which draws fuel from the auxiliary. I'm not exactly sure if this is a completely separate unit or if it uses some kind of low pressure take-off from the main pump. Both tanks share a single dash gauge which adds together signals sent from a sender in each tank. When the auxiliary tank sender reads empty, the transfer pump in the main tank shuts down.
The Long Ranger auxiliary retains all of this factory original design - and like the tank in the Navara, the outcome is that the auxiliary tank sends "full" to the dash gauge until it is about a quarter full. So when I see the single gauge begin to fall from the F mark, I know the auxiliary tank is running low and by the time the needle has passed 2/3rds, the auxiliary tank is empty. There is no light, switch or indicator to tell you any of this, you just have to know how the system works.
It is a common(ish) fault in the 200 for the auxiliary tank sender or transfer pump to fail, trapping fuel in there that the engine won't pull. While this is certainly a risk that wouldn't exist if Toyota had tried to be less clever with how this system worked, it can be worked around if it happens in the desert. The Long Ranger auxiliary has a drain valve, so you can drain that fuel into a can, remove the filler pipe from the top of the auxiliary tank and clamp it shut, then pour the fuel back down the filler spout where it will only flow into the main tank. I'd still prefer independent filler necks for the two tanks but this field repair is simple enough.
Thoughts so far
I had the new tank fitted before delivery, so it's now been there for 9 months and 14,000km. Like all good bits of kit, it does its job so well I rarely think about it. It gives me a daily driving fuel range of 1,800km before the low fuel light starts flashing, which I hope will translate to half that (900km) in expedition conditions with the camper trailer. I have a shakedown trip planned to confirm this before we hit the Canning.
I typically refuel as soon as I see the needle fall off "F", as my old man instilled in me the habit of not allowing my fuel to fall below half a tank - what if we need to evacuate in a bushfire? But every now and then, I let both tanks run down until the low fuel light comes on, just to make sure the auxiliary tank is pumping and cutting off correctly and the main tank level float doesn't stick.