Are you looking to upgrade the performance of your fuel system? Unleash the full potential of your 5.9L 12V Cummins by upgrading to a FASS Fuel System. These pumps are available in multiple optimized flow rates to match everything from stock trucks to higher-demand builds. You’re looking at a premium, complete fuel system upgrade designed to replace your factory lift pump and completely transform how your diesel delivers fuel.

These systems are designed to address common 12V Cummins fuel issues, such as inconsistent fuel pressure, air intrusion, and inadequate filtration, which can affect pump performance and long-term reliability. Whether you’re running a stock setup or have turned up the fuel, upgrading to a FASS system means cleaner fuel, more consistent pressure, and added confidence every time you get into the throttle.

Which Flow Rate should you choose?

When it comes to upgrading your fuel system, choosing the right GPH (gallons per hour) rating isn’t about picking the biggest number; it’s about matching your pump to your truck’s real-world demands. A FASS aftermarket fuel system doesn’t just supply fuel, it improves filtration, removes air/vapor, and ensures your injection system gets consistent, reliable pressure. But choosing between 140, 240, and 260 GPH? That’s where a lot of people get stuck.

140 GPH: STOCK TO MILD BUILDS (STOCK-700 HP)

• If your truck is mostly stock or running a mild tune, a 140 GPH system is a solid, reliable upgrade. It provides more than enough fuel for daily driving and light towing while improving filtration and overall system efficiency.

240 GPH: THE SWEET SPOT FOR MOST TRUCKS (600-900 HP)

• For most diesel owners, the 240 GPH system strikes the perfect balance. If you’ve added tuning, upgraded injectors, or regularly tow heavy loads, this is typically where you want to be.

260 GPH: FOR BIG POWER AND HEAVY DEMAND (900-1200 HP)

• If you’re pushing serious horsepower or working your truck hard day in and day out, the 260 GPH system delivers the flow you need. This is the go-to option for high-performance builds and trucks that live under heavy load.

The Titanium Signature Series diesel fuel Systems are the superior fuel System and filtration System in the diesel industry. This is because at FASS Diesel Fuel Systems, they focus on perfecting their systems and engineering, taking the extra steps that the competitors ignore while rushing to get product out the door. By doing this, they have a less than 1% failure rate with the motor and a design that implements unique features you can only get with FASS Diesel Fuel Systems.

• FASS Whispering Technology (FWT)was engineered to meet the stringent demands of today’s quiet diesel engines. FASS Whisper Technology was under development and testing for over two and a half years to meet FASS Fuel System’s high-quality and durability standards. FASS Whisper Technology effectively and drastically reduces the sound levels of the Signature Series FASS Diesel Fuel System to a “whisper” while at the same time increasing fuel flow rates. Our competition reduces noise levels by reducing flow rates.
• Performance Radius Cuts (PRC)are an advanced machining technique used to improve fuel flow through the FASS System by creating smooth, flowing cuts in the aluminum housing. This prevents the reintroduction of air and vapor into the fuel and prevents eddy currents from forming at the corner of a 90-degree angle. FASS Titanium Signature Fuel Systems are the only Fuel Air/vapor Separation System that incorporates these exclusive Performance Radius Cuts; lesser competitors commonly use T-Bone and square 90-degree fittings that can limit fuel flow, cause restrictions, and reintroduce air/vapor back into your fuel.
• Mass Flow Return (MFR)technology continually polishes your fuel by maintaining a positive pressure on the fuel delivered to the engine, preventing cavitation and galling/scoring, and then returning the fuel that’s not yet needed back to the tank after it's passed through the filtration process, removing dirt, air, vapor, and water. This means your fuel is constantly “Polished” (cleaned), ensuring your diesel truck always has the cleanest fuel possible. The MFR, in combination with the optional FASS Fuel Heater options, will help ensure “EXTREME” cold weather operations!
• Bolt-On Bracket Mounts: old mounting styles required drilling or welding when mounting your new System. This has now been simplified with our new bolt-on brackets that utilize your Ford Super Duty factory bed bolt, the bolt that secures your truck bed to your frame. Mounting your Titanium Signature Series System takes only minutes, and all brackets are made from machined steel for superior support and strength.