Aux fuel tank ideas

I was really interested in getting my truck equipped with an aux fuel tank. I have a 3rd gen 4runner and was thinking of this: http://www.toyota-4runner.org/off-r...4runner-f-150-tank-swap-behind-rear-axle.html

is there any way i can set up a fuel pump to go from the aux tank to my main tank?

I wanted to fill the aux tank first, then transfer fuel from that to my main tank. This would eliminate the need for two filler necks. I just need to figure out a way to set up a gauge so i know when the fuel has been transferred so i can turn off the aux fuel pump (i'm thinking of just having a switch to turn it on and off)

any input? ideas? how would you do it? is there anything in my plan i shouldn't even try?

Complicated and expensive...

...Were my first two thoughts.

I think there's a tendency to focus on "solutions" (like a spare gas tank) rather than focusing on the problem that the solution is designed to "fix."

In this case, I'd have to say it's hard to evaluate the "solution" you have in mind if we really don't understand the problem and what your needs are.

I'll be the first one to agree with you that the stock fuel tank on the 3rd gen 4runner is too small. In a perfect world, the 4runner would have a 400 mile range under normal driving conditions (would probably require a 23 - 25 gallon tank.)

So I guess my first question would be: What kind of range do you need? Emphasis on the word need, rather than want or "it would be nice."

Next, I would say "what is the simplest way of achieving that need?" For all I know the spare-gas-tank is the simplest way, but it may not be. If you only "need" to increase your fuel capacity by 5 gallons, there may be a way to carry a can on your vehicle without having to mess with the fuel system. You've already identified a couple of issues, such as how do you get fuel from the aux tank to the main tank and how do you know when the aux tank is empty?

Here is another one: Where will you put the spare tire if you displace it with a gas tank, and what will it cost for you to put the spare tire there?

Is it possible? Of course, with enough time, money and effort, anything is possible.

Is it worth it? It wouldn't be to me, but my needs are not the same as yours so only you know that. Some people take on a project like this as a hobby, not so much because they need to do it but because they want something unique and different.

It would be nice if there was an aftermarket larger tank for the 3rd gens that we could just bolt in, but AFAIK there isn't.

I'm faced with a similar dilemma, however my solution is much cheaper and more modest - I'm just going to figure a way to carry 2 x 3 gallon RotoPax cans on my roof rack. That will give me a total fuel capacity of ~24.5 gallons, which is what I had on my 1990 Montero. A bit cumbersome, yes, to mess with the racks and the cans, but much less expensive than an aux fuel tank.

Eventually, I may get a new rear bumper like the one SOAZTim has, with a carrier for 3 x 5 gallon NATO cans. Even if I carry gas in 2 and water in 1 that still gives me 28.5 gallon capacity, which is more than enough for anything in the lower 48 and Canada, and I don't plan on traveling further than that in my 4runner.

try this dont know if it will fit but hay maybe it will. price is about 1800. most important is have fun doing it.

http://www.expeditionportal.com/forum/threads/73665-Custom-35-gallon-gas-tank-for-09-Tacoma

I carry 4 20L MFCs on the roof, flat on their sides and they never leak even in ridiculous desert sun. When I don't need them, they stay in the garage. Cheap (total invested about $150?), simple, easy to share with others.

Well the mods I'm doing to the 4Runner are starting to have the “bug out” element in mind. Now that's not all I want to use my 4Runner for, i still wheel and would like to get into some longer range trips. I want to have a range of at least 500 miles.
I'm currently working on designing a rear bumper and will get working on it as soon as I finish my sliders. The reason I decided not to go with a few jerry cans is space since I plan on sticking my hi-lift, recovery gear and spare on the rear bumper. I also don't want to be a target for someone looking to steal some fuel. At my local u-pull-and-pay junk yard, a gas tank from an f150 runs about $50. I think this would be very doable even on a budget. There's just a little bit of out of the box thinking that needs to be done… There has to be a practical way to transfer the fuel over…

i remember seeing on the news some dudes that got caught stealing gas with some rig they had on their truck with a fuel pump... does anyone know how this can be done? it would essentially be the same thing...

I guess it would depend on how much money you want to spend and/or how complicated you want the setup to be. Lots of full size trucks have dual gas tanks so the mechanism to plumb in the aux tank could probably be cobbled together from another vehicle, as well as the means of switching from one tank to the other. The fuel capacity of the 2nd tank could be taken care of with an auxiliary gauge that could either go on your dash or on the A pillar (there are a couple of companies out there that make A-pillar pods for the 3rd gen 4runner.) The only sticky part would be how to fill it up, you'd have to figure a way to put in a filler.

Now, if you want to set it up so that the aux tank fills from the main tank, that is going to be a lot more complicated.

Anything's possible, it all comes down to how much money you want to spend, how much time you have and what your skills are. You might check over on the Yotatech board, they have a lot more "wild" custom builds there than we do here at ExPo.

If I was going to do a pair of tanks, I would use another pump and sending unit (gas level) in the new tank. Then add a switch that would turn one pump/sending unit off and turn the other on. So when you drive, as the level gets low in one tank you flip the switch and run off the second tank. The older pickups had this setup. You will need a second filler too.

I had a 3rd gen as well. This issue was one of the reasons I ditched it and went with an 80-series Land Cruiser since there were more aftermarket goodies...

I had two solutions I was considering when I had the 3rd gen.

The first was to get a generic, metal aftermarket aux fuel tank that would fit where the spare tire was. Then, strap it in and possibly skid plate it if necessary. I never figured out how it would be filled. But, a fuel pump to hose that could be permanently spliced into the filler tube seemed reasonable.

The other solution I saw on IH8MUD was to build a "tray" that would hold 2 or more Jerry cans in the spare tire area. The bottom of the tray would act as a skid plate. The skid plate would hinge down to reveal the Jerrys. Then, just pull them out and fuel like you normally would with Jerrys. I think there was even talk of reusing the spare tire winch or having a new dedicated winch to raise/lower the tray. I MAY be able to find the post if you'd like.

Hope this at least gives you some ideas...

BruceTS' F-150 tank swap.

how easy would it be to add an aux gas gauge? would i use the sending unit that is already in the new (to me) tank?

i actually hang out at t4r.org a lot and someone asked this question (kinda) and someone referred him to this site LOL

Gerdo, i wanted to eliminate the need for a separate filler and pluming into the stock lines buy just having the aux tank fill my stock tank instead of using the aux tank directly to fuel the truck and just having the filler tube fill the aux tank (i hope this makes sense)

G fresh, i really like the second idea you had... the only thing that would suck would be rotating the fuel stored in those tanks (unless i only mount them when i need them)

CYi5 said:

BruceTS' F-150 tank swap.

Click to expand...

the guy in this thread said if he were to keep both tanks... i'll just copy and paste the quote: Now if I were to keep both tanks, I'd wire the low fuel light in the main tank to a relay, switching the secondary pump on, transferring the fuel. For filling, I'd just add a "Y" to the filler neck so you can fill both tanks at the same time.

i really like the relay idea so i don't have to worry about even turning on my secondary pump. using a relay i can wire it to turn on when my primary low fuel light is on, and wire it to turn off when the low fuel light on the aux tank is on... i think this may work. any other ideas?

I'm actually dealing with the fuel capacity situation right now. I've got a big trip planned (Moab) and I want to add fuel capacity to the 4runner. Last year when I went to Death Valley (DVNP) I carried a 5 gallon plastic gas can (the kind you keep in the garage to fuel up your lawnmower or snowblower) and it was not a good solution - since I sleep in the back of my 4runner having a smelly gas can back there is not a good idea (and mine was wrapped in 2 black plastic trash bags but it still stunk, even after it was empty.)

Since my fabrication skills are nonexistent, I decided to go with a more low-tech idea: I have a Yakima rack which I will attach to the stock roof rack rails using the Landing Pads and control Towers, and I have a roof basket (basket case, the older, cheaper one) that I got about 20 years ago. Into that basket will go a set of RotoPax fuel packs. I like the RotoPax because they are very flat and won't protrude much into the air. They also have a reputation of being very sturdy. There are a couple of different ways of mounting and they have multiple sizes - at this point I'm thinking 2 of the 3 gallon gas packs on their universal mounting plate should be perfect.

Obviously, it's not a permanent solution but it's "good enough" for my intended uses, which would be occasional trips into the back country. Eventually I'll get a setup like SOAZ Tim has, a swing-away rear carrier with the capacity for 3 x 5 gallon cans. But for now, the RotoPax should work.

If the new aux tank is smaller than the stock tank, you could fill the aux tank and pump the gas to the stock tank. The problem would be that you could run the aux tank dry and burn up that pump. also when on a long road trip, refills would take a long time. You would have to fill the aux tank, transfer the gas to the stock tank and refill the aux tank. Having a filler for both tanks would shorten refueling time. Another problem with transferring fuel is that you really don't know how full the tank is. If you over fill the stock tank you run the risk of killing your evap. I still think that the switched tank system will be best.

An advantage to the dual fillers is that you can fill one tank for normal trips or both for extended trips. There is no reason to haul the extra weight/fuel around town.

18 gallons of gas, the tank and a skid are going to weigh ~250#.

I'm rebuilding my tire carrier/swingout to carry my spare tire, Hi-lift and one or two Jerry cans (depending on the trip). It will also have a few hidden spots for some other small things.

It would be nice on those cross country trips to drive till you need a break instead of break when you need gas.

man gerdo didn't think of all that... i did find this http://www.expeditionswest.com/equipment/tacoma/fuel_tank.html

i was thinking of adding a relay to have the pump turn off once the low fuel light turned on so i wouldn't burn out the pump... this would also make it stop transferring before it goes empty and since the f150 tank is the same size as ours, it would ensure that my stock tank wouldn't get filled all the way so i don't kill my evap. or like the guy in that link, he made the pump work in 5 minute intervals...

i like what he did about the filler neck on his aux tank, looks clean