Auxiliary Diesel Tank...

[13COBRA]

Question...

I've never run an auxiliary tank in the bed before, because I've never needed to. This year I'll be doing a lot more long distance hauling to tracks.

With just a gravity feed kit, can I run with the valve open and have the aux tank feed the OEM tank? In my head, as long as I don't open the trucks' fuel cap until the auxiliary tank is empty, it should be fine....but any input?

Thanks SVTP.

 

[Pribilof]

Never run an aux tank either but I had a Titan Tank 50 gallon replacement tank in my Ram 2500 Cummins. IMO that's the way to go. They have a 65 gallon tank for your F450.

 

[13COBRA]

Never run an aux tank either but I had a Titan Tank 50 gallon replacement tank in my Ram 2500 Cummins. IMO that's the way to go. They have a 65 gallon tank for your F450.

Yeah, but that's about 520mile range. Doing it this way, I'll have 850.

 

[_Snake_]

Question...

I've never run an auxiliary tank in the bed before, because I've never needed to. This year I'll be doing a lot more long distance hauling to tracks.

With just a gravity feed kit, can I run with the valve open and have the aux tank feed the OEM tank? In my head, as long as I don't open the trucks' fuel cap until the auxiliary tank is empty, it should be fine....but any input?

Thanks SVTP.

You got it sir. Don’t overthink it.

 

[13COBRA]

You got it sir. Don’t overthink it.

So leave the valve open all the time, don't open the truck's fuel cap until the aux tank is empty and all will be fine?

 

[_Snake_]

So leave the valve open all the time, don't open the truck's fuel cap until the aux tank is empty and all will be fine?

Are you concerned that if opened, fuel will come out of the truck’s fuel cap because the aux tank is full?

 

[13COBRA]

Are you concerned that if opened, fuel will come out of the truck’s fuel cap because the aux tank is full?

Yes. Concerned that the fuel may try to vent out of the truck's cap...since that cap is lower physically than the cap on the aux tank. Am I overthinking it?

 

[Crimson2v]

I would run a transfer tank gravity fed with a shut off valve so it’s not constantly flowing into the factory tank. When you run your fuel tank low just open the valve to fill the factory tank. That way you can prevent fuel spillage and I would also worry about the fuel return causing issues from the engine.

 

[COOL COBRA]

I’ve done this on 3 different trucks. It WILL overflow if the tank you’re feeding to gets full. What I did is drive the front tank to 1/4 tank or less, open the aux valve 1/4-1/2 open & then just drive & watch your fuel gauge. You’ll quickly get a feel of how much to open the valve by watching your fuel gauge. Mine were plumbed w/a 3/8” ball valve.
Be sure to shut the valve when you stop for the day or grass won’t grow there for years. Ask me how I know.

 

[Bullitt1448]

How about an electric solenoid valve with a dash switch to switch tanks? You could also run a auxiliary fuel gauge in the bed tank if you want, back in the day you could have wired the fuel gauge into the existing dash gauge, doubt you can do that with the electronic dash but worth looking into. Your service dept guys should be able to tell you the best way to run an auxiliary tank, they probably have the most experience with an F450

 

[13COBRA]

I’ve done this on 3 different trucks. It WILL overflow if the tank you’re feeding to gets full. What I did is drive the front tank to 1/4 tank or less, open the aux valve 1/4-1/2 open & then just drive & watch your fuel gauge. You’ll quickly get a feel of how much to open the valve by watching your fuel gauge. Mine were plumbed w/a 3/8” ball valve.
Be sure to shut the valve when you stop for the day or grass won’t grow there for years. Ask me how I know.

That's a good idea.

 

[COOL COBRA]

That's a good idea.

My career was in the oilfield. We got free fuel from the rig & 90% of us drove diesel pickups. I plumbed 3 trucks of mine like this & helped countless others do the same.
Two were L shaped tanks with a toolbox sitting on it & the last one was a square tank. Same concept. They all had a 3/8 drain on the side to screw the valve into & a 3/8 vent on top. The vent on top has to be finger tight or less, just screwed in about 1 turn or the tank will vacuum lock once you open the drain valve.
For some reason the drain was always on the passenger side. Screw in a “street L” there. It’s a Male x Female 90 degree fitting. Screw the ball valve into that & lay the fuel hose behind the tank, there’s room.
Drill a hole in the inner fender well just above the bed floor to run the hose through.
Then drill a 3/8 hole in the upper most part of the filler neck & screw in a 3/8 hose barb.
When you unscrew the truck fuel cap you can see the fuel flowing in approximately 1 1/2” down inside the filler neck. I shit you not, I drove 500k + miles with this simple setup.

 

[DSG2003Mach1]

Yeah, but that's about 520mile range. Doing it this way, I'll have 850.

Hope you got a she-wee or two with that kinda range

 

[13COBRA]

Hope you got a she-wee or two with that kinda range

Man I can usually go about 7 hours without needing to stop.

 

[roy_1031]

Yeah, but that's about 520mile range. Doing it this way, I'll have 850.

I feel like you should get close to 520 miles on the oem tank. Is your truck lifted and over sized tires? What kind mpg do you get towing, how heavy are you towing, and is the trailer enclosed? My friend with a 6.7 250 went with a titan tank and his range jumped to 900+.


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[gfcobra04]

I feel like you should get close to 520 miles on the oem tank. Is your truck lifted and over sized tires? What kind mpg do you get towing, how heavy are you towing, and is the trailer enclosed? My friend with a 6.7 250 went with a titan tank and his range jumped to 900+.


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He does get 18mpg towing 14,000lbs.

 

[Tractorman]

Question...

I've never run an auxiliary tank in the bed before, because I've never needed to. This year I'll be doing a lot more long distance hauling to tracks.

With just a gravity feed kit, can I run with the valve open and have the aux tank feed the OEM tank? In my head, as long as I don't open the trucks' fuel cap until the auxiliary tank is empty, it should be fine....but any input?

Thanks SVTP.

I ran a tank in my 2015 truck for 8 years. I left the valve open all the time. I had no issues.

I believe legally, though, you're not supposed to do that. Why, I have no idea.

 

[Pribilof]

Man I can usually go about 7 hours without needing to stop.

520 miles ÷ 75 mph = 6.93 hours

 

[13COBRA]

I feel like you should get close to 520 miles on the oem tank. Is your truck lifted and over sized tires? What kind mpg do you get towing, how heavy are you towing, and is the trailer enclosed? My friend with a 6.7 250 went with a titan tank and his range jumped to 900+.


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Yeah..leveled on 35x12.5s. I get about 8mpgs.

He does get 18mpg towing 14,000lbs.

That would be incredible.

I ran a tank in my 2015 truck for 8 years. I left the valve open all the time. I had no issues.

I believe legally, though, you're not supposed to do that. Why, I have no idea.

I might give it a go.

520 miles ÷ 75 mph = 6.93 hours

Yep. 75mph is pretty fast with a 45ft trailer.

 

[roy_1031]

Yeah..leveled on 35x12.5s. I get about 8mpgs.



That would be incredible.



I might give it a go.



Yep. 75mph is pretty fast with a 45ft trailer.

The tires kill it! My trucks an older 6.0. I leveled it and 35-12.5’s as well, cut my mileage in half! I didn’t think 35’s would do that as they not that much bigger then OE. I do want to get an aux rank as well as bigger titan tank as well. I would get an auxiliary tank that offers storage as well. Keep misc ratchet straps or whatever in there out of the cab and not flopping around the bed.


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