The Top 5 Upgrades for the L5P Duramax

Custom Tuning

Though the L5P makes nearly 450 horsepower and over 900 lb.-ft of torque from the factory, thousands of Duramax owners purchase custom tuning to push the power even further. But the benefits of aftermarket emissions-on tunes aren’t just about grunt. 

When purchased from a reputable company, custom tunes for your L5P Duramax can also improve efficiency—allowing your dollars to take you further. 



Best of all, installing custom tuning on your L5P Duramax is easier than ever. Up until recently, tuning an L5P was a costly upgrade—often running $5,000 or more! Thanks to recent software advancements by several popular tuning companies, the cost (and complexity) has been reduced significantly. 

Fuel Systems

Simply put, upgrading the fuel filtration on your L5P Duramax is “insurance for your injection system”. Though it ditched the notorious CP4 pump, the L5P’s injection components are still vulnerable to contaminated fuel. 

Despite being $5.00 or more a gallon in some areas, diesel fuel contains air, water, and debris. If left untreated, these contaminants can (and often do) wreak havoc in modern diesel injection systems like the one found on the L5P. 

With injector replacements running $2,000+ and replacement HP4 pumps coming in at $600+ for parts alone, it’s easy to see how injection system failures on the L5P Duramax get expensive in a hurry. 

That’s where FASS comes in! Engineered specifically for the L5P Duramax, our new Drop-In Series Fuel Systems protect your injection system with industry-leading filtration. 3rd-party proven to remove over 99% of the water found in diesel fuel, along with air and debris down to 2 Microns, this system provides unmatched fuel quality. 

By eliminating fuel contaminants, this L5P Fuel System Upgrade will increase the lubricity of your fuel by at least 10%—as well as:

• Restore horsepower
• Improve throttle response
• Maximize MPG
• Optimize cold-weather performance

And, unlike other options on the market, our Drop-In Series Fuel System retains full functionality of the L5P’s factory water-in-fuel (WIF) sensor. While other systems leave the WIF sensor in place, they disable it due to poor placement. If you were to reach critical levels of water in your fuel system without a functioning WIF sensor, catastrophic damage can occur. 

If that’s not enough, the FASS Drop-In Series Fuel System is a 100% bolt-in upgrade! Designed to install in your driveway, few (if any) upgrades are as simple and effective as the Drop-In Series. 

Turbochargers

As with nearly all diesel engines, aftermarket turbochargers are a popular upgrade for the L5P Duramax. While there are compound kits available, the majority of L5P Duramax turbo upgrades come in the form of drop-in replacements. 

With emissions-on tuning to compliment the improved airflow, L5P Duramaxes with turbocharger upgrades can make north of 600 rear-wheel horsepower. In competition setups, the L5P Duramax is capable of over 1,000rwhp (with supporting modifications). 



In addition to improved performance, turbo upgrades can help reduce EGTs on the L5P and optimize the driving experience. 

Cold Air Intakes

Anyone familiar with performance upgrades will likely consider a cold air intake for their L5P Duramax. Designed to improve airflow, cold air intakes are a bolt-on upgrade that increases horsepower—often without any tuning changes. 



Engineered to drop intake temperatures—cold air intakes are an easy, bolt-on upgrade that usually be installed right in your driveway. 

Additionally, many of the most popular L5P cold air intakes are a visual upgrade. While not all manufacturers offer powder coating, some offer custom colors to give owners a clean, custom look. 

Piping Kits

Expanding on cold air intakes, piping kits for the L5P Duramax are extremely popular for owners looking to maximize performance. While the details of a piping kit can vary according to manufacturer and stage, they often include:

• Intake Pipe
• Intake Horn
• Air Intake Enclosure
• Intercooler Piping
• Downpipe 

While tuning the L5P may not be required when installing a piping kit, it’s typically recommended to take full advantage of the improved airflow. 

As you might expect, custom colors or color-matching the piping kit to your truck is extremely common. 

Modifying your L5P Duramax

The upgrades discussed here are just the beginning for some L5P owners. With GM putting such a potent engine in the Silverado/Sierra, we expect to see more and more over-the-top L5P builds in the future. 



From fully built engines to trick suspensions and more, trucks equipped with the L5P Duramax only seem to be gaining popularity.