Following. Definitely jealous of this option on Landcruisers...

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Following this for sure, I'd like the extended range. Also an excuse to get a rear tire carrier

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Might take a look at what they have here https://www.summitracing.com/search...ells?PageSize=100&SortBy=Default&SortOrder=Ascending&tw=gas tanks&sw=Fuel Cells I've used them over the years for some of the builds I've done. They have great customer service and tech support that can give you some ideas on how to best do your project.

 

Looks promising, the OEM tanks might be a tad too big that I was looking at. I'll have to narrow it down to a few and see what the total cost is.

 

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Run plumbing to fill the aux fuel tank. Don't use a pump. Line from bottom of aux fuel tank to a lower spot on main tank. Let gravity feed main tank from aux tank. No messing with electrical or wiring or anything? My initial thought.

 

On motorcycles I've seen where they run the vent from the main tank up into the aux tank and let gravity feed gas from the aux into the main's vent. Then both tanks vent through the aux tank's vent. Of course it might not be so easy to mount the aux tank higher than the main tank on a X...

 

The whole thing doesn't have to be higher. I would be comfortable with the bottom of the aux tank coming 3/4 way down the main tank with the gravity fed line coming in at the half tank mark on the main tank. Once you see your fuel gauge start dropping below half tank, you know your aux tank is empty.

 

The fill solution looks like it should work.

But, why connect the two tanks together? I think it would be much easier to have a switch to control which tank is active.

You'd have to merge the two fuel lines at some point and rig the fuel pumps to work off the switch, but that seems to be about it (at least in my mind).

 

Back in the day dual tanks in pickups were common - and they used a dual tank fuel solenoid that split the line - 2 lines coming in - one going to the engine. Hit the button and it switched from one to the other. Not sure if this woudl work on the X but I don't see why not? Just google dual gas tank solenoid and see lots of examples.

The benefit I could see is you won't have to mess with the OEM tank at all - just add the second tank, split the lines, install the solenoid.

Subscribed. I would love to have a second tank

 

If a pioneer does the heavy lifting for us and gets this done I am definitely putting one in too

 

This was because old vehicles had a mechanical pump outside the tank, so you could just put two feeders coming from the pump to each tank, with one line out to the engine. Our fuel pumps are in the tank so this won't work. If you wanted a dual system, you might have to plumb it all the way into the main feeder line to the engine and would be more complicated (at least in my mind).

This is not true, as ford continued using dual tanks with fuel injection. However they did go away from them eventually, so maybe there was a reason.

However I don't think where the pump is changes anything. A normal electric fuel pump has an internal bypass, and it pumps fuel constantly. Whatever fuel the engine doesn't need is simple circulated back into the tank. Your fuel pump is on if you turn your key to run, even when the engine isn't running. So if you had a dual tank set up, I would think (I have no proof) that leaving both pumps running should be no problem, as the one not enabled through the splitter would just continually circulate fuel without using any. At least I think that would be the case - I have never looked into it that deeply.

 

There are a myriad of tanks systems that manufactures put out (like dual saddle tanks in Audi's that are connected by a line and have two pumps, one to just throw fuel into the other side) or Land cruisers with dual pumps and tanks etc.. My point is the old system with the exterior pump was easy to run two separate tanks off the same pump.

I don't think with ours it would be that easy. I'm not sure on the routing going out to engine and if messing with that portion would cause issues. If you had the aux pump turn on with the main pump, and plumbed in a return line from the main tank to the aux tank there is still the issue of getting the fuel back to the aux tank since it will be mounted higher. You would need another pump or something...my head hurts just thinking about it lol!

 

I would agree with you, that a transfer pump into the main tank would likely be easier.

 

Just be aware this will drive the DTE (distance to empty) calculations crazy as it is watching the fuel level in your main tank to calculate, and it thinks you only have ~18 gals. Your current MPG reading will probably be OK as that is being derived from the flow rate.

 

Should be ok, as stated the DTE is based on your current MPG and current level in the main tank. So, if my tank gets near empty and DTE says like 50 miles, and I switch on the aux pump to fill up the tank, it should recalculate the DTE as if I just filled the tank at a service station no? Keep in mind the aux pump will not be continuously replenishing the main tank, only when I turn it on. If it were to be constantly on maybe there would be an issue.

 

Just going to say, the photobucket fiasco has made this a huge PITA trying to look at what people in other forums have done! Anyway, after talking with a mechanic friend of mine, top filler style tanks might be too tight to use in the location I want (mostly due to the cross member for the spare tire hanger). Looking at some side filler options, more than likely a fuel cell. A lot of fuel cells are available with a sending unit and pump (and they tell you the sending unit's ohm reading for full and empty which is nice).

If that is the case, I might consider using the rear plastic quarter panel as a filler point rather than try and get the Nissan Patrol filler neck to work. I'd like to use the driver's side, but the evap canister is there so I'm not sure there is enough room. I'll take the quarter panels off and see what can be done there. Also should this project cause non resolvable codes to come up or be a huge failure, the only thing I would need to return to stock would be a new plastic quarter panel and a new rubber hose for the filler neck to replace the piece I plan on splicing into.

I'm in the process of buying a second vehicle. I sold my Corvette that was driven only 2k miles in the last two years to free up some capital. I hated washing it (currently in a condo) and my fiance could not drive it so it just sat. When I find a second vehicle, this will be moving forward much quicker since I won't need the X as a DD. I'll definitely post up a proper parts list, then start a new thread in the how-to for install.

 

The VQ is a returnless system so the bypass is in the fuel pump in the tank, I would recommend not messing with a splitter.

By far the easiest way would be the original idea of having a transfer pump from the aux tank to the main tank. You wouldn't want the aux pump running all the time because once it's empty it will burn up the pump. You could use a fuel level sender to create an automatic shutoff, the fuel sender is just a resistor so the output is a variable voltage, when the sender gets to a specific voltage you could have the aux fuel pump shut off.

the factory fuel sender and fuel gauge react fairly quickly so you wouldn't have to worry about only transferring fuel when your main tank is almost empty, I have filled my truck while it was running and the increase in fuel level was registering almost immediately.

As for the DTE and MPG calculations, who cares, they are incorrect anyways. My odometer is around 10% slow and the speedo is about 5% with 255/85/16 tires

 

Could you elaborate on the auto shut off and link a part? I'm more of a visual type. A momentary switch to activate the pump with an auto shut off would be ideal, especially if the switch is accidentally activated.

 

as to the evap system, as long as you have everything sealed up, you should not have a problem. the main problem would be that the ECM can only monitor the pressure levels inside the main tank, and all purge/vent actions would be based on that. The vacuum that is pulled on the system is just engine vacuum, with the purge valve allowing and stopping air to enter the intake from the evap system. The vent valve opens and closes to allow pressure to release when the engine is off.


That is essentially how the EVAP system works.

 

Got myself a second vehicle, will probably start putting parts together for this next week.

 

Took some more accurate and in-depth measurements today. After looking at clearance for the departure angle from the rear bumper, the tank can't be all that thick, maybe a height of 10 inches, but more than likely a bit less because I plan on mounting a skid to protect it. Another option is running one rectangular tank before the cross member the spare hangs off of and possibly a second aux tank in front/underneath the spare tire cross member. Initially I was hoping for around 20 gallons so I am now looking at fuel tanks to fit the dimensions, more on this next week.

I'm going to run something like this for my gauge and to activate the pump. I have to check with them to see what resistance the gauge is rated for. Typically sending units are 0-90 ohms, but it varies.

 

Cut the spare tire brace out.

 

It's not that simple, even if it was gone, the height of the tank would still be limited to about 10-12 inches for the departure angle and to leave room for the lines on top. I will cut the sides (it is u shaped) and keep the top portion. Then I'll fab a brace from it to the other cross member towards the front. That will serve as mounting for the tank and skid.

 

This is exciting

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Oh, I know what it's like under there. I shoved my shocks up as high as I could get them after the body lift.

 

I would look into a single high volume fuel tank.

How about swapping in the fuel tank from a Titan?
The standard Titan tank should be around 28gallons and the long bed 08 Titans had a 36gallon tank.
If your lucky, the wiring to the tanks may be the same.
If you decide to swap in an Xterra pump it may be a crap-shoot deciding to use a Titan fuel float or a Frontier/Xterra.

 

There's no room underneath for the titan tank. The stock tank takes up as much room as possible where it's mounted

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Maybe something like this as another option
https://www.pickupspecialties.com/Titan_Fuel_Tanks/spare_tire_auxiliary_fuel_tanks.html

 

Too big. I offroad my Xterra so I have to stick with a certain height limit.

 

So settled on a tank from RCI. If I remember it is under the street aluminum fuel cell category with dimensions of 30x12x9" with a 15 gallon capacity. It wasn't common finding a tank with a sending unit and a remote side filler provision given the height restriction. I believe the spare is approx 10" wide for perspective, plus I can cut away at the crossmember that held the spare if I have to.

 

Do you have a link to it?

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