IMPROVING A 2012 LML DURAMAX

tube and some modification to the factory fuel basket within the stock tank to feed that hungry lift pump, but we’d skipped that part knowing we’d soon be installing this big tank and we hated the thought of dropping the fuel tank twice.

Because we had opted to skip the fuel pickup modifications, our lift pump was running a little louder than it should because it was working harder to pull fuel through the restrictive stock pickup. We knew installing a sump kit with the new Titan tank would be the ultimate upgrade for supplying fuel to the Titanium pump. Deviant Race Parts (DRP) of Coeur d’alene, Idaho, has been selling a billet fuel sump kit for a few years and now offers one with a fuel return port. The new design makes installation simple and allows the lift pump return line to plumb to the bottom side of the tank rather than through the fuel fill neck. Returning fuel below the fuel level within the tank leaves less chance of unwanted air being introduced into the system, which would create more aeration to the fuel and more work for the lift pump. The large feed port will feed fuel directly to the lift pump, reducing load on the pump, quieting it down and hopefully extending its lifespan. The sump also makes the fuel feed the lowest part of the system, which can eliminate some of the concerns with pump cavitation at low tank levels.

All of this was done in a home garage using basic hand tools, and while a two-post life and the truck six feet in their air would’ve made it easier, a couple of jack stands and some finagling to get the tank in/out from under the frame wasn’t too tough. This truck is currently averaging around 17.3 miles per gallon and the Titan tank

 Fuel sumps are nothing new to the market, but the latest version from Deviant Race Parts offers a built-in return port. Rather than returning fuel back through a vent tube or the fill neck, which can create even more aeration to the fuel, the sump-fed return can reduce fuel aeration and help maintain proper fuel supply to the lift pump, regardless of fuel level. You can see how the sump’s internal divide allows the system to work at efficiently feeding quality fuel flow to the pump. Returned fuel can be pushed back into the pump, always below the fuel level, to keep additional air from entering the system.

 Titan’s Super Series tank and a fuel return sump kit from Deviant Race Parts are on the docket for installation in Part 6 of our lengthy 2012 LML Duramax build. The massive 57-gallon replacement underbody fuel tank will nearly double the range between fill-ups, while the sump kit aids the previously installed FASS Titanium’s ability to draw and return fuel to and from the tank more efficiently.

 Using a hole saw, the pilot hole was drilled in the center and the 3-1/4” hole could be bored all the way through. Once the cut is complete you’ll want to be sure to deburr the edges and vacuum or blow out all the debris from inside the tank.

 At this point it’s time to overcome the fear of drilling a 3-inch hole in the bottom of a brand-new fuel tank. The optimal place for this return-style sump is directly below the factory pickup, and the mold of the Titan tank made this an easy installation.

 The billet clamp plate slides up in through the hole and will center itself due to the exacting machined surface.