6.7L POWER INCREASE
I recently acquired a used 2011 Dodge Cummins 6.7L. The truck came to me with an AFE cold-air intake already installed. The truck performs great now, but my question is what kind of programmer would you recommend that wouldn’t risk damaging the engine? I have read that just installing a turbo-back exhaust system on this truck could result in a trouble code unless a programmer or ECM program is added. I’m just looking for a little better fuel economy and a little more power to pull my 30-foot RV trailer.
Kyle Weston Via Email Reports from a few years ago, when the 6.7L was introduced, indicated that 14-15 mpg was somewhat typical when it was driven unloaded on the open road. The emissions regulations have had their effect on diesel fuel economy. All the newer diesel pickups incorporate a DPF (Diesel Particulate Filter), which traps nearly all of the soot particles that make their way out of the engine. DPFS slowly accumulate soot over time, which usually requires a periodic regeneration to oxidize (burn) the accumulation. Burning the accumulated soot requires fuel, which is injected into the exhaust system upstream of the catalytic converter (called active regeneration). This is raw fuel that contributes nothing to pushing the truck down the highway. As a result, Dpf-equipped trucks produce fewer miles per gallon than their pre-dpf predecessors. Truck owners who use their trucks to tow are reporting less of a hit to fuel economy because the average exhaust temperature is at a level that burns the accumulated soot without the need for raw fuel. This passive DPF regeneration occurs when exhaust temperatures are maintained above 1,100 degrees F for lengthy periods of time while out on the road. Any truck modification that alters programming, turbo boost pressures, fueling, or exhaust aftertreatment can result in the truck being out of compliance with the EPA emissions regulations. With a little searching you’ll likely find aftermarket manufacturers and vendors that offer “DPF Delete” kits that include exhaust system modifications and programming changes that prevent active regeneration. Delete kits are intended to be used off-road or in competition, but some find their way into street trucks. Vendors I spoke with recently do not install products like this, but will sell them for
a customer installation. In recent years, the EPA and some states have become more aggressive in enforcing the regulations. Fines are a possibility.
Moe at Usdieselparts.com told me that the H&S XRT Pro Race, Mini-max and Black Max tuners all offer a range of possibilities for the Dodge 6.7L. Most owners should see a slight increase in fuel economy with one of these tuners—perhaps 1.5 to 2 mpg. In addition to modifications in injection timing and fuel maps (that offer a small bump in fuel economy), you can also increase performance, correct for speedometer error due to a tire size change, and monitor some engine parameters. Whether a tuner, downloader, or plug-in device, they all present a risk to drivetrain durability, depending on how the truck is driven.
Dpf-back exhaust systems look great, and can change the way the truck sounds, but don’t expect much help with fuel economy. The real restriction in the exhaust system is the Diesel Particulate Filter. Good luck.