Factory Auxiliary Sub Tank Install (1 Viewer)

[LandCruiserPhil]

DANGER WILL ROBINSON - You are solely responsible for harm you may cause yourself or others following anything below.


It started with a $45 factory sub tank. The tank was completely bare with loose baffles inside and everything needed to be fab’d from that point.

Testing the tank to make sure it was safe to cut on.

I cut out the sending unit to use as a template for the future fuel pickup and get the loose baffle out. The fuel bucket inside the tank was in great shape and remains

Welded up the tank, pressure test, and Paint to match. Time to fab some brackets.

I fab’d brackets using some of the factory concepts and some of my own. They are hinged on one end like the factory. To avoid nutzerts I fished bolts 2 bolts per bracket for a solid mount. For the other end I cut a hole and slid in flanged nuts drilled small holes and tacked them in place. Much better mounting set then factory, in my mind anyway

 

[LandCruiserPhil]

More pictures of brackets and the way they attach

Next was the pickup tube, I used the factory sending bung as a template and bent up some 3/8” gas line (thanks Saddletramp), fab’d a cap and welded it up. The gasket for the pickup tube on the aux tank bung is the same as a Toyota Yaris, who’d a thought.

 

[LandCruiserPhil]

Test fitted the tank and marked where the main filler pipe needed to be cut with the new filler neck. I had an used dual filler neck with slightly angled outputs but from my research a filler neck with 90° outputs yielded more capacity. This is were the budget install went out of budget when I purchased a brand new filler neck, O well

Cutting the main tank filler tube is a little scary with the strong smell of gas when you first cut through the filler pipe. Figuring I have done a lot of stupid things in the past and here to tell the story Im good for another. Each tank gets it own filler and vent that line up nicely. The fit is very tight but rock solid with everything clamped together.

 

[LandCruiserPhil]

I had big plans for becoming a fueling station for everyone. As I struggled with a plan my wife of reason said I thought this aux tank was for you and what was wrong with the way you have done it in the past, I thought you liked things simple. Now if you run out of gas I cant help you and you can blame my wife.

I fab’d this y pipe thing’e to dump fuel into the main tank via the vent line by a transfer pump. Stupid simple and very effective way of transferring

Mounted an in-line pump for the transfer pump up high and out of the way along with a filter, all outside of the tank.

Time to test….pump runs but I get nothing?? I realize my free pump is a gravity feed pump and will not work. Going with ‘its not the ***-up but the speedy recovery’ I started looking through my junk and come up with 3 Holley Blue pump from my X Trophy truck days. Re fab my mounts and install the Holley blue something I should of done from the beginning anyway being a faster, vane style self priming, and much better pump all around. Now I have transfer and super fast with Holley rated at 110gph.

I will be using a rear window defroster switch Im having relabeled with a reverse negative to give the factory look (not installed yet).

End results

 

[LandCruiserPhil]

Common asked questions –

How much did it cost
$45 tank
$350 dual filler neck
$75 in miscellaneous parts
A bunch of time fab’n stuff

How much does the tank hold
14.75 gals
I can transfer all but 1qt. of gas out of the tank with my set up.

How do you know how much is in your sub tank
I keep 2 gals in the tank for normal driving. When the fuel light comes on I purge the aux tank. When I travel I fill the aux tank 100% and purge it when the light comes on. I have run aux tanks past and this system works great and I always have fresh fuel in my aux tank.

How do you the fuel transfer to the main tank
Push the button, it can be done at any speed any time.
You are able to tell by the pump sound when the transfer is done.

Is there problems with removing the baffles
Having run aux/custom tanks in the past as big as 36 gal without baffles I say no.

Testing results
It was super nice with a new range of ~500 miles to take a resent trip without needing to add fuel. The difference in out of town fuel cost is ~.50/gal and up so it may take a long time to recoup the cost but not worrying about fuel needs is where the big payoff is.

 

[george_tlc]

Nice job. I've had my oem subtank installed for about 14 yrs now and can't imagine not having that reserve fuel available at a press of a button. Not having to worry about fuel when out on a camping trip is a nice feeling versus wondering when to have to turn around or to curtail some extra exploring.

Curses 100x on toyota for skimping on it for the US market.

cheers,
george.

 

[Muddy1]

Very nice work! Looks fabulous, and I actually understood your aux fuel strategy!

Congrats!

Muddy1

 

[clownmidget]

I had always thought of going the super cheap route as you have done but had envisioned cutting the tank in half at the seam between the top and bottom and then making it larger - just to the point that it completely fills out that space above the bottom of the frame rails. Seems Toyota still wanted to have that spare tire assembly down there and without it, I've always wanted to have a slightly larger volume. I dig that Holley pump - is it & the filter enough to stop any siphoning back from the main tank to the aux tank? Also, since you aren't able to roll a lip on the main tank filler tube (where you cut it) you might want to consider using a little longer hose and double clamp it.

 

[LandCruiserPhil]

Nice job. I've had my oem subtank installed for about 14 yrs now and can't imagine not having that reserve fuel available at a press of a button. Not having to worry about fuel when out on a camping trip is a nice feeling versus wondering when to have to turn around or to curtail some extra exploring.

Curses 100x on toyota for skimping on it for the US market.

cheers,
george.

I reviewed your excellent factory OEM install several times and was not as willing to spend the money and source the parts needed. Simple has worked in the past for me so why change my old ways.

I the past my old 60 carried 36gals and my old 40 carried 42gals. After needed gas on the trail 3 times in my 80 it was time to address. I will also look forward to peace of mind.

 

[hoser]

Looks good, Phil! I might suggest swapping out those hose clamps for the constant tension type.

 

[LandCruiserPhil]

I had always thought of going the super cheap route as you have done but had envisioned cutting the tank in half at the seam between the top and bottom and then making it larger - just to the point that it completely fills out that space above the bottom of the frame rails. Seems Toyota still wanted to have that spare tire assembly down there and without it, I've always wanted to have a slightly larger volume. I dig that Holley pump - is it & the filter enough to stop any siphoning back from the main tank to the aux tank? Having used vane pumps on past aux installs I dont think it will permit any back siphon. Also, since you aren't able to roll a lip on the main tank filler tube (where you cut it) you might want to consider using a little longer hose and double clamp it. I guess I could of easily added a lip but didnt see it as problem on the suction side. The Holley blue is a low pressure (14psi max) high volume pump

 

[LandCruiserPhil]

Looks good, Phil! I might suggest swapping out those hose clamps for the constant tension type.

Yes a good suggestion. There are always better ways to do things but I rely on my past history and experience of using the same methods for more years then I care to remember. Again the system is only under pressure when transferring and then only a max of 14 psi on the down hill side of the pump.

 

[george_tlc]

I reviewed your excellent factory OEM install several times and was not as willing to spend the money and source the parts needed. Simple has worked in the past for me so why change my old ways.

I the past my old 60 carried 36gals and my old 40 carried 42gals. After needed gas on the trail 3 times in my 80 it was time to address. I will also look forward to peace of mind.

Yep, I was lucky when I got my setup. I had gone down to MAF to pickup a kaymar tradesman rack that I had swapped some welding work for and figured to stop in a SOR. Marv gave me a quick tour (helped having the aussie accent ) and showed me a subtank setup he had that he was considering for his 80. So I bought the whole setup off him on the spot so other than the fuel transfer circuit I developed and sourcing some of the hoses it was a pretty complete kit of stuff, including the overhead gauge cluster that I later sold to someone on mud.

Simple is good, knowing exactly what you have implemented makes it easy to fault find any issues later - not that the whole subtank scheme is complicated

Having the extra fuel on reserve is a good thing. I figure that a full subtank should get you back to a fuel station pretty well anywhere in the contiguous US.

In oz I have a 160l tank in my old nissan diesel. That gives me a safe 700+ mile range and then when needed I take up to 5 jerry cans of extra diesel for a further 400+ miles. I'm planning a trip back to western oz in a month or so that has about 800 miles between fuel stops...

cheers,
george.

 

[Saddletramp]

Very nice job. What's next?

 

[LandCruiserPhil]

Very nice job. What's next?

If I spill the beans somebody might beat me to it

 

[Chris FJ80]

Love it. Nice job. I hope to be doing mine in the fall

 

[Muddy1]

OK, here's a noob question.... Instead of having a dual main/aux setup, would it be possible (or simpler) to simply put in a much larger single tank into the 80?

Thanks,

Muddy1

 

[Onefastrx7turbo]

Very nice Phil!!!

 

[LandCruiserPhil]

OK, here's a noob question.... Instead of having a dual main/aux setup, would it be possible (or simpler) to simply put in a much larger single tank into the 80?

Thanks,

Muddy1

They are available no knowledge on install difficultly

 

[iptman]

Is that a non-OE cross member between your frame rails?