Discovery 4 / LR4 Auxiliary Long Range Tank

#1
For some time I have been trying to source an auxiliary tank for my Disco4 (I still refuse to call it LR4 but in fact it is a US spec Disco 4). Over the past 2 years of wheeling I realized that one of the biggest issues with my car is its limited offroad range. 375hp V8 has its benefits (especially at high altitudes) but gosh it has its drawbacks. The problem was that Disco 3/4 (or for that matter any LR) aux tanks are not made in the US but are quite popular in South Africa and Australia.

To the best of my knowledge, only one aux fuel tank was ever installed on a US spec Disco 3/4 and in that case it was done by the ARB team which tried to figure out whether they would like to import Australian made Disco 3/4 aux fuel tanks. They encountered lots of issues (fault codes popping etc) and as a result they don't import aux tanks (I believe you can special order Disco 3/4 aux tank with them but don't know anyone that actually did it). As a result, I think this is the first SUCCESSFUL (no fault codes / system fully functional at all angles/capacity of the aux fuel tank) installation of an aux tank for US spec Disco3/4....

Recently I got my hands on an Australian Long Range Automotive Aux Tank (29 gallons) that was meant to fit all Disco 3/4.... Well that's where the story starts. The tank does fit "almost" all Disco 3/4s except for US specification as in the US (for some gas emission regulation reasons) LR had to completely redesign fuel intake/pipes/flow system. What that meant is very early in the process we realized that... nothing fits (and by nothing I really mean no single pipe/fitting/hookup etc provided by the manufacturer fit the US spec fuel intake). My buddy and I spent long hours staring at the diagrams of US spec fuel intake and came up with a fully custom hook up. We encountered and conquered tons of issues..... (1) how to connect aux fuel tank to the liquid/vapor separator (not present on any non US LRs); (2) how to connect the aux fuel tank to the fuel intake system (the original system was made for diesel and didn't fit) / location of the connection is also very tricky due to gravity (the fuel has to actually flow to the regular tank and due to LR fuel pipe set up it isn't that easy; (3) the fuel pump provided with the system has a meager capacity of 23g/h which meant that it would take 1.5hrs to transfer all the fuel (we installed a second fuel pump with a capacity of 95g/h that works together with the manufacturer's pump - the transfer of all 29gallons takes minutes now...) etc etc...

Week after the installation I can say the following - it is WORKING! The system is fully operational and there is no approach angle issues (the tank design is actually perfect as it follows the internal lines and thus fits perfectly).
 

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#2
More pictures attached - finished project :)

This is my ultimate North American expedition rig (still not a diesel but as close as it gets to it with an aux tank) :) The aux tank added 29 gallons to the existing 19 gallons which means that with the two jerry cans that fit on the top of my baja rack I have a total capacity of 58 gallons which averaging 15mpg gives a range of 870 miles!!!

My Disco 4 has now:

1. Terrafirma hidden winch with a Superwinch 9.5xi
2. Tactical rovers side (rock)/tank/transfer case sliders
3. Front OEM A Bar with two rigid industries D2 lamps (wireless on/off)
4. Kaymar rear bumper with two tire set up and aux lights
5. Internal mounted HAM radio
6. Disco3 wheels (30 mm spacers installed)
7. Custom Baja Rack (50in and dual nato jerry can set up)
8. Oztent foxwing
9. Long Range Automotive Aux tank (29 gallons)

To be installed in the near future:

1. Green Oval Experience air suspension override
2. Roadshower
 

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#3
Looks great! The truck has come a long way since I met you a couple of years ago at Pismo at the NCLR/SCLR trip and your truck was pretty much bone stock IIRC.. Keep up the good work!
 

proper4wd

Expedition Leader
#4
375hp

Nice LR4 and nice mod... please be sure all the fittings that you used are rated for fuel. Some plastics will "melt" very quickly when exposed to gasoline.
 
#5
375hp

Nice LR4 and nice mod... please be sure all the fittings that you used are rated for fuel. Some plastics will "melt" very quickly when exposed to gasoline.
HI - Funny thing about the connections - LR stock rubber connector which connects the two fuel pipes (see pics) actually began coming apart.... I don't know if it is actually rated for fuel as something weird was going on with it... :) It was kind of melting....
 

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#7
I am very impressed and interested. Not quite there on pulling the trigger on something like this. More importantly, you manage to avg 15 mpg. I am stoked when I get 13. Mileage dropped significantly when I added Nitto Tires, plus all the TR armor.

Back to setup,

How is it filled?
Do you need to turn on pump and transfer fuel?
If so, what happens when it is full?
 
#9
I am very impressed and interested. Not quite there on pulling the trigger on something like this. More importantly, you manage to avg 15 mpg. I am stoked when I get 13. Mileage dropped significantly when I added Nitto Tires, plus all the TR armor.

Back to setup,

How is it filled?
Do you need to turn on pump and transfer fuel?
If so, what happens when it is full?
HI - re your MPG please check your air filters. Mine increased to 15/18 when I changed those.

The tank is filled as normally you fill fuel. Aprox 50% goes to regular tank and 50% to auxiliary (sometimes more to one or the other). You have fuel guauges for both tanks so it is easy to figure out which tank got filled. The transfer of fuel takes minutes (press the button and watch the fuel gauge increase for the regular tank and decrease for the aux tank). No brainer. You would have to pump 19 gallons plus 29 gallons to have both tanks full. Engine is utilizing only the regular tank and thus once the fuel is gone from the regular tank you can transfer the fuel from the aux to regular. Does that answer your questions?
 
#10
Do you have a schematic of what you did for the fuel lines and vapor system?
Sorry no schematics - I can answer the questions but please look at the pics. They should guide you at least a bit. You will see there a Y crossing (this is how we connected the regular fuel flow line to the aux tank - left line goes to aux and right goes to regular tank). The pictures are also labelled and thus you will see a pic for liquid/vapor separator connection (bigger tube is the vapor / smaller tube is the fuel over flow - vapor needs to go to the liquid vapor separator while the fuel overspill line goes directly back to the regular tank). Picture titled "Fuel Pump (manufacturer) connection" shows the connection from the aux tank to two fuel pumps.
 
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#11
Boy with 29 additional gallons of gas (6.073 lbs/gallon * 29 = 176.117 lbs) plus an additional spare, not to mention bumper, winch, sliders, rack, skids, etc, that LR4 must be pushing some serious weight when fully loaded with fuel, cargo and people. Would love to know what it's tipping the scales at.


BTW - being in California, what do you think your chances are that you're gonna pass the visual inspection for smog? Or do you plan to swap it out every 2 years when its smog time? You may want to paint it black to help not draw attention to it if you plan to keep it on.
 
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#12
Boy with 29 additional gallons of gas (6.073 lbs/gallon * 29 = 176.117 lbs) plus an additional spare, not to mention bumper, winch, sliders, rack, skids, etc, that LR4 must be pushing some serious weight when fully loaded with fuel, cargo and people. Would love to know what it's tipping the scales at.


BTW - being in California, what do you think your chances are that you're gonna pass the visual inspection for smog? Or do you plan to swap it out every 2 years when its smog time? You may want to paint it black to help not draw attention to it if you plan to keep it on.
SMOG etc - the aux tank fuel lines are connected to the original set up and thus they do not affect how the fuel emission system works (this was the BIG issue as we didn't want this system to be throwing fault codes etc.). Why would they have an issue with that? I never saw any SMOG folks looking underneath the car to verify the fuel lines set up.


Yep - it is heavy. The good news is that Disco4 can handle it and the air suspension can very easily accommodate for the added weight.
 
#13
SMOG etc - the aux tank fuel lines are connected to the original set up and thus they do not affect how the fuel emission system works (this was the BIG issue as we didn't want this system to be throwing fault codes etc.). Why would they have an issue with that? I never saw any SMOG folks looking underneath the car to verify the fuel lines set up.
Most smog shops should be checking underneath the car to verify the CATs are in place and no modifications to the exhaust pipes, fuel lines, etc...this is actually called out in the steps for visual inspection that must be checked. Remember a smog check is both a visual inspection AND an OBD inspection. Just because its not throwing a code does not mean it'll pass visual as anything added to the emissions equipment (exhaust, intake, fuel, etc) must be approved by CARB. My recent SMOG on my LR3 had my additional frame mounted air tank called into question...had to show it wasn't in any way tied to fuel or emissions. By definition, you've modified the fuel system which means an automatic failure on visual inspection since its not CARB approved. Your best bet will be to get to know you smog guy really well, but even then most won't be willing to put their job/lic on the line to turn a blind eye. Also, every 3 smogs you need to go to a TEST ONLY location which is even more thorough. Don't mean to spook you, but you should plan for a PLAN B b/c its highly likely to get called out for failure in the visual inspection. With your LR4 being visually modified (rack, bumper, winch, etc), this is a red flag to the smog checker to look more closely at the vehicle as there is a higher likelihood there may be emission modifications too (which in this case would be true). I personally would swap it out before every smog check....last thing you want is having a flag in the system that your car failed a visual inspection due to a non_CARB approved modification as it'll make every future inspected be done under a microscope.

Gotta love the eco wacks in CA ;)
 
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#15
Will let you know once I am due for the SMOG. I will try doing it at a local shop. I never saw them looking at anything under the car and thus it would be the first. Let's see but even if I have an issue, it takes one hour to disconnect the whole system :) I think you are overestimating the zealousness of SMOG folks or maybe you had a bad experience... Still for what I am trying to achieve (ability of long off-road travel without worrying about fuel) it is worth it.
 
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