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Simple and Effective Auxiliary Fuel tank

Thanks CG, I'll be seeing Julian soon I'll ask on the type of tank he fitted, with both tanks full I get at least a range of 600 miles @ about 18mpg, just done a rough calculation and you are probably right on the size.
Similar range to what i get and mines pretty much a full oem set up. I personally wouldnt want much bigger a tank. I see it as a sub tank rather than a long range tank.
 
To get a 80l tank above the spare would be a interesting design. The oem fits like a glove with little extra space up there.
 
do the two tanks both have breather pipes ?

when filling up the 140l long ranger on my Hilux, and pump shuts off at £100 or 100 litres, i put pump nozzle down back into holder, wait a couple of seconds, then pick up the pump nozzle then start filling again - it resets the display of cours, but when you go pay two transactions then show up on receipt fo same pump. lady at till at a BP garage told me to do this, to save having to go into shop and pay twice.
i have done this at other garages. at another BP station i use the lorry pump, it doesnt stop at £100, like the other pumps at same station do, and also has a higher flow rate

not sure if the 2 fills without paying one at atime qwould work at supermarket stations
 
I allways use the lorry pump when i can. The wrist saver isnt deactivated neither...
 
The tank that Trev and Ed fitted is very square and I can see how it'll hold 80L over the OEM sub that I have. The OEM is a lovely fit, but the tank is not a true rectangular shape, it's very contoured and in that way loses the extra fill. That being said I'd like to confirm the capacity of the square one with some dimensions. Best we got out of our sub from full to chug chug oops time to swap over was 241 miles. Worst I have had has been 190. That's quite a difference for the same type of driving.
 
Chas do you have any details of photos how you had yours plumbed in please?
 
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That's like my normal tank at times Chris :lol:

As Andy has asked do they have breathers?
I'd imagine being a petrol mine would need a breather on a sub tank too, there's no atmospheric vent so would have to plumbed into the main tank vent :think:
 
Think the breathers were shared actually from what I could see during the install.
 
The tank that Trev and Ed fitted is very square and I can see how it'll hold 80L over the OEM sub that I have. The OEM is a lovely fit, but the tank is not a true rectangular shape, it's very contoured and in that way loses the extra fill. That being said I'd like to confirm the capacity of the square one with some dimensions. Best we got out of our sub from full to chug chug oops time to swap over was 241 miles. Worst I have had has been 190. That's quite a difference for the same type of driving.

Hi Chris. I just ran a tape over the tank. Allowing for 2mm of steel (it is actually 1.6mm) the internal size in cm is 101.8 x 51.6 x 17.6 which should hold 92.45L. There is a little contouring which I estimate reduces the capacity by around 2L. When pressure tested the tank came out at 90L. However a wheel carrier will not fit under this tank without adjustment, which was my intention as my car has an external carrier.
 
Very nice Byron. Planning a remote trip soon?
 
That's pretty decent Byron and as you say it's a nice simple design.
 
That is a good capacity and no extra pumps etc to fit
 
Did the main tank have to be modified to add an inlet from the aux tank lower down than the standard inlet?
 
No Jon. Basically this is a simple cascade / overflow set up where the fuel has to pass through the aux tank into the main tank. You could set it up I suppose to fill the main first then overflow into the aux then drain back again but that would be harder I think and involve more mods. This did away with a large section of the main filler pipe which was shortened to go into the aux, then the filler neck was re connected to the new tank. The new tank was high enough to provide enough fall into the old tank. My only thoughts were that this effectively increases the head on the old tank so you do need to make sure that you have nice tight connections and a good seal around the sender unit or you'll have derv welling up under the carpet.
 
Did the main tank have to be modified to add an inlet from the aux tank lower down than the standard inlet?

Hi Jon. Chris describes the filling arrangement correctly but there is also another connection in smaller diameter pipe which runs from the bottom of the aux tank into a hole drilled into the side of the main tank about 50mm above its bottom. The aux tank drains into the main through this pipe as fuel is consumed.
 
Hi Jon. Chris describes the filling arrangement correctly but there is also another connection in smaller diameter pipe which runs from the bottom of the aux tank into a hole drilled into the side of the main tank about 50mm above its bottom. The aux tank drains into the main through this pipe as fuel is consumed.

That's what I thought, just useful to know thanks :)
 
The ML55 I borrowed off Ian for a bit has an aux / expansion tank behind the back axle and just uses a balance pipe low down on the two tanks to join them and an extra breather which is what I had been thinking of copying but I haven't checked it it would work on a 100.
 
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The ML55 I borrowed off Ian for a bit has an aux / expansion tank behind the back axle and just uses a balance pipe low down on the two tanks to join them and an extra breather which is what I had been thinking of copying but I haven't checked it it would work on a 100.

Sounds like that would work well.
 
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