Installing Smeding Diesel’s S400 Kit On A Fourth-Gen 6.7L Cummins
Right out of the box, the 6.7L Cummins is a potent performer. But while its variable geometry Holset HE351VE provides instant throttle response, promotes huge off-idle torque, and offers a factory exhaust brake function, its track-record for long-term reliability isn’t exactly commendable. Oftentimes the VGT actuator stops functioning, but occasionally mechanical turbo failure transpires. When either of these problems occur, the owner is faced with a decision to either stick with the problematic VGT or start over with a proven, fixed geometry replacement. Thanks to the displacement increase the 6.7L enjoys over its 5.9L predecessor, a BorgWarner S400-based turbo can be run with no tangible sacrifice in drivability—even with a completely stock fuel system.
With the factory Holset VGT beginning to check out on our ’12 Ram 2500 test mule, the products offered by Smeding Diesel caught our eye. The Texas-based company has earned a reputation for developing high-quality, comprehensive turbo kits in recent years, and its pricing is on-point. We reached out for one of Smeding’s S400 turbo kits, its one-piece stainless-steel exhaust manifold, True-Flow intake horn, and the company’s grid heater delete. Following the install, and despite the truck still sporting the factory fuel system, it was immediately apparent that the newfound airflow had uncorked the engine’s true potential. If you’re on the fence about ditching the factory VGT, don’t be. Adding an S400 to a 6.7L Cummins is one of the best mods you can make to an ’07.5-current Ram.