Red Chili's

I begin wondering the possibility about installing an auxiliary fuel tank on my 1998 4Runner. It would be nice to drive in a longer 4wheeling trip without a frequency "pit stop".

I have seen the Padro with V6 engine (LC 90 Series) has it as standard in Australia and optional in some countries. I believe a Padro has a similar frame as 4Runner, please correct me if I am wrong. An auxiliary tank mounted in the area where a spare tire located under the 4Runner. The fuel filling neck location is same on both models. I don't know if it can be a direct bolt-on installation without a major modification.

Anyone has an idea where I can get a kit? Who can import the parts from Japan or any countries? I am planning to build a custom rear bumper with spare tire carrier very soon. So, there will be a room for aux. fuel tank. Your help would be greatly appreciated. Thanks!

Woodbert

I know the Prado shares the same frame as the 2003 Surf but I don't think the same is for previous years.

I saw a new Prado delivered last week, and they have one on the showroom floor and I don't recall a spare fuel tank.

jx94148

A few Tacoma pickup guys have put a junkyard tank from Jeep Cherokees (XJ) where the spare goes. They are about 10.5 inches tall and tapred to a semi-wedge shape on the rear for clearance. Also they are plastic with sheetmetal armor around the bottom. The filler neck is on the left side, same as your existing tank. The tough part is cutting the body and fitting the door and securing the neck. A feed and vent return are run from the Jeep electric in tank pump to the front tank and back by drilling holes for pipe fittings. A cab mounted switch controls the electric pump to move fuel from the back tank to the front.

I picked up a Jeep Wrangler (YJ) 20 gallon tank for $50 including pump and sending unit, filler neck, cap... everything. I think it will be too big to fit in my truck. I want one from a Suzuki Samuari. They are tiny at 11 gallons but dimensions are easy to fit on my truck. The neck is on the right side which is good for my application. I just need to find an EFI one for the in-tank electric pump. I'll probably also use a petcock from a junkyard motorcyle so I can pump it either to the front tank or through a hose to another truck if needed on the trail.

There are a few companies that make custom tanks to any dimensions you want. They are really expensive though. Also some people have used fuel cells from Summit racing products, also pretty expensive for my taste.

$80 for a junkyard tank is about all i'd spend on it.

jx94148

Also NWOR and Downey sell tanks for a similar setup. I'm not sure about there the filler is on those.

I see that our member WATRD has a 15 gallon Downey aux tank. I hope he rings in and shares details of his setup.

DH6twinotter

I've been tinkering around with the idea for a while. I noticed that under my 4Runner, there is alot of space in front of the stock tank. I wonder if an aux. tank could fit there? My 4Runner is a 2wd though, so maybe the front driveshaft takes up this space on you all's 4x4s. I dunno. Just a thought. A small air tank might fit there too. I think the fuel tank is mounted on the opposite side on you all 3rd gens, so I'm not sure how different that would be.

Have fun.
DH6twinotter

ALee27

has anyone ever relocated their original tank to the spare tire location? this would fix the problem w/ the driveshaft hitting the gas tank skid so it wouldnt limit the amount of lift in the rear.

Cebby

Saw a writeup somewhere on the web where that was done on a 2nd Gen. I'll post it if I can come across it.

WATRD

I DO have the 15 gallon Downey aux tank under my rig The filler neck is located in the wheel well.

I don't know if it would work on a runner or not, but I could easily take photos, were someone interested. The nice thing about going with a manufactured tank is the federal approval. At least if you get rear ended and the tank goes up, you are not going to be charged with unsafe modifications that way. It uses a fuel pump to transfer fuel to the main tank.

jx94148

Hi Rob. I'd like to know more about your setup. Did you have to drop the front tank to do the plumbing? What had to be done to the front one to pull it off?

WATRD

Fair enough then...

The install was a breeze. I did it in my driveway in about three hours, by myself, one sunny summer afternoon. The first step is unpacking. The box contains a bewildering array of hoses, fittings, wires, and accessories. At this point I *almost* put it all back in the closet. But, I decided to stick it through and started laying out all the parts to get organized. After leafing through the instruction sheet, I began to get a feel for the task at hand.

The first step is to make some connections to the tank itself. The tank is divided into two chambers to help prevent slosh and has a variety of vents, pick ups other spots to attach stuff. When the tank is fully fitted, it begins to look like some sort of steel medusa. Of course, it is all that plumbing that earns the tank it's DOT and DOE approvals.

The next step was surprisingly easy. Since the tank is designed to allow continued use of the spare tire hanger, it has a channel in the center to allow the stock hoist to stick through. Thoughtfully enough, Downey sized that hole just such that you could use the hoist to lift the tank into position. Stuff the retainer through the tank and hoist away.

Once the tank is in position, (it straddles the crossmember that the hoist is bolted to), it requires that four holes be drilled into the crossmember. The tank has ears welded onto either side that are pre-bent to match up to the shape of the crossmember and those tabs have holes drilled through them so marking and drilling is a breeze.

Now that the tank is bolted into position, it's plumbing time. Running the lines requires a fair bit of time spent up underneath, but the instructions make it pretty easy. Vents go to the existing vents, etc. I have plenty of room to sit upright under my rig, but if you are lower than me, this definitely will require some jackstands, a lift or a pit.

The outlet line goes to a small external pump, then routes into a nifty fitting shaped like the symbol for "pi" that inserts into the vent line for the stock filler. You do not have to drop the stock tank.

The filler for the aux tank mounts up under the drivers side wheel well and requires a small bolt be inserted through a hole drilled through the wheel well. This is another spot where I would worry about a stock height rig. To fill the tank, your reach above the tire and remove the filler cap. On my rig I have plenty of room, but it's going to be REALLY tight on a non-lifted truck.

Finally, figure out where to mount the switch and run the wires back to the pump You are now ready to fill it up.

I am not terribly pleased with the filler location, it gets pretty grimy, so I intend to relocate it. I am also not happy with the lack of a gauge. It makes it a task to remember how much fuel you have left. I would also like to see some sort of auto shut off on the pump, I keep forgetting to turn it off and I am sooner or later going to ruin the pump. My plan for now is to install a timed switch so that it will run for 10 minutes or so, then shut off.

jx94148

Good info, thanks.

Yota_clear

What is the possibility of using the main fueler pipe to fill the aux tank and just pumping from the aux into the main to completely fill both tanks?? What is the flow rate of the aux pump, that would make a difference in the possibility of it being feasible??

WATRD

I thought about that, but a couple of problems came to mind. First, you would have to come up with a way to cap off the stock filler then and since it takes about 15+ minutes to transfer the entire AUX tank to the main, you would be standing at the gas station for a long time. Plus, I like being able to decide which tank get's filled. There are times that I just don't need another 105 pounds of gas hanging back there.

ringo234

I not sure how it's done but I'm pretty sure the Downey Aux tank is gravity fed to the main tank.

It would nice to fill both takes from the stock filler location. There must be a way to acomplish it.

Wouldn't having the filler pipe in the wheel well cause a rubbing problem with larger tires?

Andy

WATRD

Nope. Gravity feed did not meet the DOT/smog regulations, so it feeds the main tank with a small fuel pump.


I have wheeled it hard with 32's, 33's and now 35's and so far it hasn't touched That was my first thought when I saw the set up, but it hasn't proven to be true.

Of course, as I mentioned above, I suspect that it might rub in a stock height rig.

Runner003

Just Called Downey, They are in the works for a 99 4runner Aux tank. Still months away.

garrett1478

nice. i was wondering when this thread was gonna be updated.

FilthyRich

what are your plans for the spare??

Runner003

24 fitness, you mean For the 4runner... Roof Rack with the spare tire Carrier

Macgyver

Okay keep in mind that my 4Runner is under major construction and nothing is finished, I'm still in the designing phase. Also please don't comment on the removal of the catalytic converter and it's effects on pollution and it's illegal and blah blah blah, It's a real pet peave of mine when people go off on those issues in forums. My 4Runner will never be inspected or smogged so let's just leave it at that. In the aux-tank pic you can see the space where I'll be building my aux fuel tank. It should be a little bigger than the stock tank at ~20-22 gallons & it'll be made from stainless steel. The dual fuel filler is from an OZ 80 series Land Cruiser. The filler has a knob by the cap to select which tank needs to be filled. Of course none of this is possible without deleting the catalytic converter and installing the muffler it's place. I went through 2 mufflers(magnaflow 24", Flowmaster 70) before I settled on a 2.5" Walker Quietflow muffler from a Cadallic application. Since the catalytic converter really cuts down on the sound I wanted the quietest muffler I could find that would fit, It's just a little louder than my old TRD setup mostly due to the side exiting exhaust. I don't smell any fumes with all of the windows down but I may snake the exhaust to the back of the vehicle in the future if room allows. Should be done between 1 and 5 months