Auxiliary Fuel Tank Setup

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Joined
Jan 25, 2020
Messages
3
Wondering if anyone has any experience/expertise they can lend to my addition of an Aux Fuel Tank.

I have a 2017 Ram 3500 DRW (diesel) truck towing a Montana 5th Wheel, and am looking to add a 92 gallon auxiliary fuel tank to the bed and have a direct feed to the filler line going to the factory gas tank. From my research, the system can be setup to either gravity feed or use an inline fuel pump.

Here are the items I am looking to install:
Tank: Amazon.com: Dee Zee DZ91768XB (92 gallon) Auxiliary Diesel Fuel Transfer Tank - Black Aluminum: Automotive
Connector: Amazon.com: Southern Truck 11408 Fits 2013-2019 Dodge Trucks Diesel Auxiliary Install Kit, 1¾" Fill Line: Automotive

I plan to have a manual ball (shutoff) valve connected to the tank, but would like to be able to open this valve and "turn on" the flow from inside the cab while driving. I do not want to have to stop and manually turn the shutoff on/off while traveling. I also don't want to leave the gravity feed open once the tank is full for risk of spillage. The gravity feed should process approx 12-15 GPH. Assuming 10 MPG while towing, this would only increase the factory tank fuel level by 6-9 gallons per hour. So worst case scenario, it would take 5 hours to "refill" the factory tank while driving.

My thoughts are to add a solenoid and/or a inline fuel pump to the setup that can be activated from within the cab.

The fuel pump would allow the tank to fill much faster, but would not stop the gravity flow effect once the factory tank is full.
The solenoid would stop the flow, but would be need to be open a significant amount of time to refill the tank (heat issue?).
Utilizing both seems to the way to go, but it also seems to be overkill and add a lot of failure possibilities to the mix.

Any input or experience would be appreciated. Thanks.
 
Joined
Nov 2, 2019
Messages
2,386
Location
WA, MT or somewhere else!
RV Year
2018
RV Make
Newmar
RV Model
Mountain Aire 4047
RV Length
40'
TOW/TOAD
2014 Honda CR-V
While I have never had such a setup, I have friends that do. Most of their setups function as a transfer system where fuel is moved from the auxiliary tank to the OEM tank via pump. I don't see why gravity feed wouldn't work, but I think it would be pretty slow and managing the level of the OEM tank would take some attention. Certainly, there are fuel-rated 12V ball valves available. The "fuel-rated" aspect is important for safety reasons.

Why not just go with the conventional fuel transfer system?

TJ
 
Joined
Nov 3, 2019
Messages
433
Location
TGO Titusville FL
RV Year
2015
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Newmar
RV Model
Dutchstar 4369
RV Length
43
TOW/TOAD
2014 Honda CRV
Jeff,
I think you are trying to over complicate the system. Simple ON/OFF valve, and a 12V pump will be fine. You have to stop every 2-3 hrs to walk around, make a pit stop etc. Flip the switch and replenish your main tank in 10 minutes.
Here you can find a pump to fit your requirements www.enginegearonline.com. I know the owner and will get you 10% discount if you decide to get one
 
Joined
Jan 25, 2020
Messages
3
The purpose for the aux tank is so that I don't have to stop every 4-5 hours to refuel.

TJ&Lady. How would the fuel pump stop the flow from continuing to siphon and overflow the tank once turned off?
Buly. I don't stop every 2-3 hours. (Or at least I don't want to :) $240-$600 pump is not worth it to me.
 
Joined
Nov 3, 2019
Messages
433
Location
TGO Titusville FL
RV Year
2015
RV Make
Newmar
RV Model
Dutchstar 4369
RV Length
43
TOW/TOAD
2014 Honda CRV
On diesels, there is usually a return line that returns the unused fuel back to the tank. If that’s the case, you will need a 6 port valve to feed and return to the same tank Light Truck 6-Port Motor Driven Valve On Pollak
This way you can switch from the cabin from main to AUX tank without stopping.
 
Joined
Nov 3, 2019
Messages
433
Location
TGO Titusville FL
RV Year
2015
RV Make
Newmar
RV Model
Dutchstar 4369
RV Length
43
TOW/TOAD
2014 Honda CRV
Let us know how you did it, so we can all benefit from your experience.
 
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