Project Double-Duty Ram: Adding More Diesel Capacity

This 2018 Double-Duty Ram 3500 is being built to be a versatile pickup. It wheels, it camps, it hauls, it tows, and it gets groceries. It has been used around town most of its life, but also makes long-haul runs from time to time, thus more fuel capacity could provide both convenience and a longer cruising range.

After lifting the truck and upgrading to 37-inch tires, the owner mounted a matching spare tire in the bed. There was little need for the stock-sized spare under the bed, so it could be removed. This would leave a perfect open area to fit one of Titan Fuel Tank's Spare Tire Auxiliary Fuel Systems (STAFS). In addition to its line of extra-capacity stock replacement tanks, the company manufactures spare tire tanks to fit a number of applications. In this case, the added tank adds 30 gallons of diesel on board.

The Titan tank is constructed from military-grade, cross-linked polyethylene and weighs only about 30 pounds. The tank kit includes everything needed for installation, including an added filler neck that can be mounted on the outside or inside wall of the bed. Once diesel fuel is in the Titan tank, it can be transferred over to the main tank using the provided fuel pump. When commanded from the Titan electronic controller in the cab, the pump pushes fuel into a hose that taps into the tank vent line going to the factory fuel tank.

The installation is not complex and can be done with common mechanic's tools. The trickiest part of the project is probably routing some of the hoses in tight spaces under the bed. The truck now has about double the available fuel capacity compared to stock form. With a total capacity exceeding 60 gallons, the truck will surely remain fueled long beyond the bladder capacity limit of any driver.