Hey guys,
Just sharing how the subtank came out.
Sometime ago I managed to find a direct fit petrol tank from Moskvich Aleko from 1986. It holds 55 litres (14.5gls) and fits perfectly in the spot of the original spare tire carrier, which I moved to the back with the gate and rear carrier from a 96 Hilux Surf.
The original longitudinal spare wheel support brackets were used and modded to attach it to the frame. Also made two sub brackets that continue the shape of the tank so it doesn't touch the body, and made two straps to hold it in place, like the strap on the main tank.
The only mods I did, were to cut the filler neck at the right spot and place a custom three-way pipe uniting the two tanks, and add another threeway pipe on the vent pipe hose to vent them correctly.
Later bought the two valves used on KZJ95, when equipped with a subtank, and made a bracket that they attach to, which is bolted to the fuel tank strap bracket. The return valve is visible in one of the pics but pick-up is attached to the front of that same bracket.
A friend gave me the sensor from his spare main tank (not the sender gauge assembly) that I attached to the pick-up pipe from the Aleko, which was also a little modded to fit another pick-up pipe, as the original single petrol pipe was repurposed as the return.
The electrical diagram is very simple - one wire feeds 12V+ to the valves directly powered from the subtank switch, which also splices to the newly added dash lamp for low fuel signal and then goes to the sensor on the pick-up pipe which is mounted about a quarter up from the bottom, after the fuel filter, giving me about a 3rd of fuel left. All loads are then grounded.
From there, it was only hoses and rubber padding to run around under the truck and tighten a bunch of hose clamps. I did scrape the original paint off of the subtank and covered it with epoxy primer and then black paint to preserve it for the time being. When mounted it sits at the same height of the tail pipe and hitch, so it doesn't interfere with the depart angle, and should't be a problem when going over rock. I can always add some simple shield.
Now the 4Runner has about 125 litres of diesel and a minimal travel distance of 1000. currently it's giving me 12.5l/100kms which is equivalent to almost 19mpg. It is loaded to the birm of GVM tho.
The best part - diesel fuel around here in Bulgaria is around $5.50
Here a couple of pics from the project.