Cummins ISB performance upgrades can improve power delivery, throttle response, fuel efficiency, and reliability in trucks, buses, RVs, and other commercial applications. The ISB family includes several generations and ratings, so the best upgrade path depends on the engine's displacement, model year, emissions level, and intended use.

Turbocharger Upgrades

The turbocharger is an important part of the ISB's airflow system. Depending on the engine generation, the ISB uses either wastegated or variable-geometry turbocharging. Cummins describes the VGT system on newer ISB6.7 engines as being optimized for strong low-speed torque and improved drivability.

A properly matched replacement or upgraded turbo can improve airflow while maintaining useful low-end response. For commercial applications, selecting a turbo based on the engine's original specifications and power requirement is more important than simply choosing the largest available unit.

Intake and Airflow Improvements

Improving airflow is another useful area to consider. A clean high-quality air filter, leak-free intake plumbing, and properly maintained charge-air cooler can help the engine maintain efficient airflow.

On newer ISB6.7 engines, Cummins combines high-pressure common-rail fuel injection with turbocharging and electronic engine management to balance performance, fuel economy, and emissions.

Fuel System Upgrades

The fuel system should also be maintained before adding performance components. Newer ISB6.7 engines use a high-pressure common-rail system with electronically controlled injectors. Cummins states that the system can operate at injection pressures of up to 1,800 bar on certain applications.

Useful supporting upgrades can include:

• High-quality fuel filters
• Fuel-pressure monitoring
• Properly serviced injectors
• Clean fuel delivery
• Replacement fuel-system components
• Correctly matched calibration

Cummins also highlights advanced fuel filtration as an important part of protecting the ISB fuel system.

Exhaust and Cooling

A healthy exhaust and cooling system is essential when an ISB is operating under sustained load. Before adding performance hardware, inspect the exhaust system, turbocharger, cooling system, radiator, hoses, and charge-air cooler.

For example, Cummins lists ISB6.7 EPA 2010 ratings from 200 to 325 hp and 520 to 750 lb-ft of torque, depending on configuration. Newer 2017 ISB6.7 truck and bus versions can reach up to 320 hp and 1,200 Nm of torque in certain configurations.