Discovery 4 / LR4 Auxiliary Long Range Tank

[michalc]

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).