Paccar PX-9 Vs Cummins L9: Which Engine Will Perform Better?

Growing your brand and expanding into new areas, you need the flexibility to switch equipment while still receiving excellent service. Vehicles powered by Paccar PX-9 or Cummins L9 come with the best, most reliable service system in the United States.

The engines in your trucks aren’t just machines that move; and they’re also the heart of the vehicle. Paccar PX-9 Engine is specifically designed for superior performance, efficiency, and power.

Using Cummins’ new L Series engines, the company gives its customers what they want. Cummins’ 2017 L9 diesel engine provides outstanding productivity, as well as high power-to-weight ratios.

Paccar PX-9 Vs Cummins L9: what’s the better engine? Keep reading for the answer. You’ll find out soon.

Paccar PX-9 Vs Cummins L9: Quick Comparison Table

SpecificationsPaccar PX-9Cummins L9
Configuration:-Inline 6 CylinderInline 6 Cylinder
Displacement:-8.9 liters8.9 liters
Horsepower:-260-450 HP260-380 HP
Bore x stroke:-114m x 145m102m x 120m 
Oil capacity:-29 U.S. quarts24-28 U.S. quarts
Dry weight:-1,695 lbs1,695 lbs
Peak torque:-860-1250 lb-ft720-1250 lb-ft
Clutch engaging torque:-500 lb-ft 575 lb.-ft.
Governed speed:-2100-2200 RPM2100-2200 RPM
Certification:-EPA 2021EPA 2021
Base warranty:-2 years/ 250K miles/ 400K km2 years/ 250k miles/ 402k km

Paccar PX-9 Vs Cummins L9: Whats The Difference Between Them?


According to Paccar PX-9, its power-to-weight ratio is among the best in its category. Both heavy-duty & medium-duty versions are available, and this engine provides superior performance and durability.

The higher-end versions are suitable for heavy-duty vehicles but can also be used with medium-duty vehicles. The PX-9’s lower end has features usually reserved for heavier trucks. It has cylinders with replaceable water liners and a bypass oil filter.

With high-strength components and features like reusable cylinder liners, high-quality engines aren’t just more durable; Cummins L9 also has a higher residual value.

L9 delivers exceptional performance under the most challenging workloads. The Cummins L9 “After Treatment System” and engines are designed and constructed in-house. As a result, they offer customers better quality, uptime, dependability, and efficiency.

Cummins L9 comes out on top in this comparison. Cummins L9 meets Environmental Protection Agency (EPA) and Department of Transportation (DOT) regulations regarding greenhouse gas emissions and fuel efficiency.


Paccar PX-9 can produce up to 380 horsepower and 1,250 lb-feet of torque. Providing efficiency and durability, the engine helps to reduce operating costs, improve productivity, and reduce maintenance. Your Kenworth dealer can provide you with brochures regarding engines.

For exceptional performance, the L9 shares the same technology as the heavy-duty ISX12 and ISX15. There is an XPI fuel supply, a high-capacity controller module from Cummins Turbo Technologies, & the patented VGTTM turbocharger.

Ranging from 260 to 380 horsepower (194 to 283 kW), with 550 pounds-feet for clutch engagement. For better control, the front-engine power takeoff (FEPTO) and rear-engine power takeoff (REPTO) options are available.

Cummins L9 wins. The Cummins L9 has been improving its performance record for years. Due to its highest power density, the L9 is suited for even the most demanding medium-duty tasks.


Paccar PX-9’s main promotional focus is its power to weight ratio, making it more powerful than PX-7. A Paccar PX-9 engine with an 8.9-liter displacement in the marketplace today is one of the most powerful engines.

Featuring heavy-duty components such as a replaceable wet liner, bypass oil filtering, roller-driven cam followers, and a piston-targeted cooling system.

Cummins designs develop and support each component as one fully integrated system, including air handling and exhaust after treatment.

Cummins L9 engines are well known for their reliability in medium-duty applications. Cummins’s’ brand-new aftertreatment system is 70 percent smaller and 30 percent lighter compared to the previous model, resulting in greater efficiency.

Cummins L9 won the game easily as well. It features a bypass oil filter, robust roller followers, and focused piston cooling. These features extend the life of the machine. No matter how tough the work environment is.


As a mid-range engine, the Paccar PX-9 is truly all-around. The PX-9 variations are a great fit for your truck, whether you want a medium-duty truck to have more power.

If you’d like some of the simplicity offered by a medium-duty engine, the PX-9 is an excellent choice for your heavy hauler.

A PX-9’s ECM is responsible for accurately controlling all engine functions so that fuel economy and output are maximized.

With its newest generation of L Series engines, Cummins is helping customers redefine efficiency in 2017.

Cummins L9 diesel engines are the most productive and have the most favorable power-to-weight ratio in their class. Designed to keep running for years, Cummins L9 diesel engines are the most reliable.

The faster and more accurate engine means greater uptime, as well as a 15% improvement in fuel economy than previous engines.

The Cummins L9 includes a turbocharger, fuel injectors, water pump, fuel pump, air compressor, and several engine sensors.

To meet trade cycles and specific needs, extended coverage plans are available.  So, there is no confusion that Cummins L9 is the clear winner. 

Maintenance & Warranty

The Paccar PX-9 has a similar maintenance schedule to the previous models, with the exception of having the coolant filter installed, which alters the formula to 15-15-15-200.

Compared to the PX model, the PX-9 comes with a 2-year warranty & 250,000 miles, as well as plan extensions.

For decades, Cummins L9 engines have provided reliable service, even after the original warranty period has expired.

They offer extended warranty plans with up to 2 years and 250,000 miles and 402k kilometers coverage on any registered parts & labor. 

Paccar PX-9 Vs Cummins L9: Price

In the United States, the price of the Paccar PX-9 is around $15,800.

In the USA, Cummins L9 Diesel Engines are also priced at around $15,800.

The price range can vary and can increase or decrease depending on many factors. These include model, year, capacity, purchasing country, and more.

Paccar PX-9 Or Cummins L9: Which One Should You Choose?

What are the differences between Paccar PX-9 Vs Cummins L9? How do you decide which to buy? The 8.9 liter Paccar PX-9 engine is among the most powerful engines, capable of moving heavy payloads with ease.

This engine is suitable in both heavy-duty and medium-duty configurations, allowing you to save money, improve productivity and reduce maintenance.

However, fuel economy is up to 1.5% more economical on the Cummins L9 Productivity Series engines compared to the other models. You should go with your preferred one counting on various factors.


Is the Cummins L9 a good engine?

The latest Cummins L9 engine delivers class-leading torque and power ratings, unmatched power to weight ratio, as well as reliability & uptime you want from Cummins.

The L9 series engines have higher fuel efficiency than previous models by up to 1.5%.

Is a Paccar engine a Cummins?

Cummins engines will be badged Paccar even though they are built by Cummins. In other words, the truckmaker is able to brand its own powertrain and brand itself vertically.

Similarly, Cummins also supplies 4-liter and 6-liter midrange engines to the European truck maker DAF owned by Paccar.

Who makes PACCAR PX-9?

Kenworth has produced “informative brochures’ ‘ on Paccar’s new PX-9 and PX-7 engines. The system was designed in compliance with the “Environmental Protecting Agency” (EPA) requires that all engines for the 2013 model year must have an “On-Board Diagnostics’ ‘ (OBD) system.

Last Word

Paccar PX-9 Vs Cummins L9 is already clear to you. A targeted piston cooling system and a bypass oil filter reduce internal temperatures in the Paccar PX-9, extending engine life and protecting the engine components system.

In the Paccar PX-9, the ECM achieves optimal performance and fuel economy through precise control of all engine functions.

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