We took our time with this story. Unlike some of our product installs, which are last-minute thrash fests to bolt on parts, run to the dyno, and report the findings, we've been examining the hidden mileage benefits of some commonly installed products for the past six months and 15,000 miles using our '07 1/2 Dodge Ram Mega Cab with the emissions-neutered 6.7L Cummins.
That's not to say the 6.7L isn't a performer. Its 350 hp and 650 lb-ft move the 8,000-pound barge with authority. But thanks to EPA regulations and Dodge's insistence on coming to market with a 2010 emissions-compliant package a few years early, the first string of 6.7L trucks weren't without their glitches.
For starters, the newfangled diesel particulate filter (DPF) and the use of exhaust gas recirculation (EGR) on these 6.7L engines results in a lot of soot entering the turbo and abysmal fuel economy numbers when compared with the early '07 trucks that came with the 5.9L engine. But since the computer management in the 2010-compliant trucks is more complicated, convoluted, and intertwined with every aspect of the vehicle, you can't just slap on an "off-road" exhaust and piggyback a few programmers to boost performance and mileage. The ECM is harder to crack and is able to store more codes and log fuel, timing, and boost parameters. Bottom line? It knows if it has been modded, and because of the high number of warranty issues with these trucks, the factory has begun to look for any reason it can find to void warranties.
 The factory Dodge airbox draws...  The factory Dodge airbox draws cold air from an opening in the fender only. With the stock exhaust system and all of its filters in place, air flow into the engine is just about adequate, but there's always room for improvement. |  The stock air tube is insulated,...  The stock air tube is insulated, baffled and uses a large-vaned silencer that's pressed into the tubing. Some argue that the curved vanes of the baffle actually help direct airflow into the turbo. While we didn't have the chance to conduct any flowbench comparisons, we can see how the baffle cuts perceived turbo and exhaust brake noise at all boost levels. |  The S&B intake kit (PN 75-5015)...  The S&B intake kit (PN 75-5015) does away with the entire factory intake up to the turbo. The kit uses the company's seven-layer filter, which in S&B's independent ISO testing, proved 99.16 percent efficient compared with the factory paper element's 99.83 percent efficiency, yet it flowed more than 59 percent better. |
 The stock 6.7L paper filter...  The stock 6.7L paper filter element is an elephant, with lots of tall pleats. Notice the distinctive outline of the stock airbox opening after less than 3,800 miles of driving. |  The S&B filter comes pre-oiled...  The S&B filter comes pre-oiled and the cotton gauze material is nicely bonded to the rubber shell. Notice the smooth flow potential as viewed from the inside of the filter. |  The actual S&B installation...  The actual S&B installation is straightforward and almost boring. The only notable exception is on the mass airflow (MAF) sensor. The sensor wiring harness makes contact with the S&B intake tube before the terminals are able to fully seat. Per S&B's instructions, we left the MAF loose until we clipped on the connector, then we finished tightening the mounting screws. |