As your diesel build evolves, it’s a common question: “Can I upgrade my existing FASS Fuel System for more fuel flow?”
The answer is yes—you absolutely can.
If you’ve added performance upgrades like larger injectors, an upgraded injection pump, or more aggressive tuning, your fuel demand has likely increased.
In those cases, stepping up to a higher GPH (gallons per hour) FASS system—or upgrading components within your current system—can help ensure your engine gets the fuel it needs.
When Should You Consider Upgrading?
The vast majority of FASS Fuel System owners have plenty of fuel flow but if you’ve made upgrades such as:
- Larger injectors
- Upgraded CP3 or dual CP3 setups
- Bigger turbo(s)
- Aggressive custom tuning
Then your current FASS system might not be sized appropriately. To be clear, this isn't common—FASS Fuel Systems are overbuilt and conservatively rated. For example, a 165GPH FASS Fuel System for a 6.7 Cummins might be rated for 900hp, but will typically support 1,000-1,100+hp without skipping a beat.
However, if your fuel and tuning setup has managed to "outrun" your existing FASS setup, you might benefit from increasing your GPH.
Upgrading to a higher-flow system can help maintain:
- Consistent fuel pressure
- Proper injector performance
- Reliable operation under load
- Ample fuel delivery at higher horsepower levels
What Does an Upgrade Involve?
Upgrading a FASS Fuel System isn’t always as simple as swapping one part (though can might be). Depending on your current setup and your target GPH, upgrades may include:
- Pump/motor assembly changes
- Different fittings or plumbing
- Line size adjustments
- Electrical components
- Mounting considerations
Because every truck and build is different, the exact components needed can vary.
The Best Way to Get the Right Setup
To make sure you get exactly what you need (and nothing you don’t), the best approach is to contact our team directly.
We’ll help you:
- Identify your current system
- Understand your fuel demand
- Recommend the correct upgrade path
- Ensure compatibility with your setup
You can reach us through any of the following:
- DM us on Facebook, Instagram, or TikTok
- Call us at (636) 433-5410
- Email: [email protected]
