Turbocharger & Air Intake System for Cummins NH855 Engines

The Cummins NH855 is a legendary heavy-duty diesel engine that delivers exceptional power and reliability in marine, industrial, and generator set applications. A major factor in its performance is the turbocharger and supporting air intake system. Together, these components increase the volume of clean, pressurized air delivered to the cylinders, resulting in improved fuel efficiency, reduced emissions, and maximum horsepower output.

The Turbocharger on the Cummins NH855

The turbocharger is one of the most critical components on the NH855. It uses exhaust gases to spin a turbine, which drives a compressor that forces more air into the combustion chambers. By increasing the air density inside the cylinders, the turbocharger allows the engine to burn more fuel efficiently, generating higher power without significantly increasing engine size.

Key Benefits of the NH855 Turbocharger:

• Boosted Power Output: Delivers the horsepower needed for heavy loads and continuous duty cycles.

• Improved Fuel Economy: Better air-to-fuel ratios lead to more complete combustion and lower fuel use.

• Reduced Emissions: Cleaner combustion minimizes smoke, soot, and harmful exhaust gases.

• Durability in Demanding Conditions: Engineered to handle high exhaust temperatures and extended operation.

The NH855 turbocharger is specifically matched to the displacement and airflow requirements of the 855-series, ensuring reliability even under sustained high loads in marine propulsion or power generation.

Supporting Air Intake Components

A turbocharger cannot operate effectively without a properly designed and maintained intake system. For the Cummins NH855, Diesel Pro Power supplies essential components to keep airflow clean, unrestricted, and stable.

Cummins AirSep System

The AirSep system is a vital upgrade for many NH855 and NT855 engines. It combines high-efficiency air filtration with crankcase ventilation, removing contaminants, oil mist, and airborne particles before they reach the turbocharger or cylinders.

• Large 6-inch throat diameter ensures unrestricted airflow.

• Crankcase blow-by management prevents oil carryover into the intake.

• Prolonged turbo life by protecting compressor wheels from contamination.

• Cleaner combustion that improves power and reduces visible smoke.

This system is especially beneficial for marine operators, where exposure to salt, moisture, and fine airborne particles makes intake cleanliness a top priority.

Hump Hoses and Intake Adaptors

The turbocharger on the NH855 connects to intake piping through reinforced hoses designed to absorb vibration and withstand high airflow pressures.

• 6” to 5” hump hose – Adapts large-diameter filters or AirSep units to the turbo inlet.

• 6” to 5.5” hump hose – Provides flexibility for different intake setups where space or alignment is a factor.

• Reinforced construction resists heat, oil, and constant vibration.

• Smooth internal surface minimizes turbulence, ensuring efficient airflow into the turbo.

By keeping these hoses in top condition, operators prevent costly intake leaks that can reduce turbo efficiency and allow unfiltered air to enter the engine.

How the Turbocharger and Intake Work Together

The NH855 turbocharger and intake system are designed as a single airflow pathway:

1. Air enters through the filter or AirSep system, which removes dirt, dust, and oil mist.

2. The turbocharger compresses the air, raising its density for more efficient combustion.

3. Hump hoses and piping deliver the compressed air to the intake manifold and cylinders.

4. Clean, pressurized air mixes with fuel, generating powerful combustion strokes that drive the engine.

When these components are properly maintained, the NH855 runs with maximum efficiency, lower emissions, and longer turbocharger service life.

Maintenance and Common Issues

Like all high-performance components, the turbocharger and intake system of the NH855 require regular inspection. Common problems include:

• Turbo lag or reduced boost – Often caused by clogged filters, failing seals, or worn bearings.

• Excessive smoke – May indicate restricted airflow, damaged hoses, or oil entering the intake.

• Whining or grinding noises – A sign of worn turbo bearings or compressor wheel damage.

• Air leaks at connections – Caused by cracked hump hoses or loose clamps, reducing turbo efficiency.

Replacing intake components such as hump hoses, filters, or upgrading to an AirSep system can often resolve these issues before they cause major damage.

Diesel Pro Power Advantage

With over 40,000 satisfied customers worldwide, Diesel Pro Power is the most trusted source for Cummins NH855 turbochargers and intake system components. We supply only high-quality, tested parts designed for exact fitment, ensuring quick installation and long-lasting performance. Our fast worldwide shipping and expert support mean you can keep your NH855 engine running at peak power with minimal downtime.