2016 Nissan Titan XD Cummins Engine 2-Stage, 4-Mode Turbocharger Explained

The turbocharger in the 5.0-liter Cummins turbodiesel engine mounted in the new Titan XD pickup truck is made to boost power at all levels. This video explains how it works.

The 5.0L V8 turbodiesel from Cummins that powers the new 2016 Titan XD is a monster of an engine consider that its 555 lb-ft of torque will be powering a half-ton pickup truck. It also features a unique Cummins M2 Two-Stage Turbocharger that works in four modes to boost both high and low engine speeds.

It's a series-sequential turbocharging system that has two different turbos in one unit, using the smaller to facilitate low-flow requirements and the larger for higher flow. This gives the dual advantage of having a smaller, faster-response turbo for the lower end and a higher-volume, larger turbo for the higher end, eliminating most of the turbo lag traditionally associated with large block diesel engines.

A patented rotary valve controls the airflow between the turbochargers, opening ports that allow bypass or waste gate functionality with exhaust after-treatment thermal management. It's a complex-sounding, but relatively simple system that gives the big V8 Cummins its long torque curve.

The video shows the four modes the turbocharger unit acts within. High-pressure mode provides maximum airflow and bypasses many of the other systems to avoid bottlenecks. In Low-pressure mode, the unit uses different routing to push smaller volumes of air with a smaller fan along with exhaust gas mixing for reburn. Wastegate mode offers maximum power for high-torque requirements, such as when starting a load pull or climbing a hill under load. Finally comes Regen mode.

The video shows how the systems work, how the bypass valves move airflow, and more.