ROI Series | 2001-2010 Chevrolet/GMC with 6.6 Duramax
Jake H • January 8, 2025

Please note: MPG improvements depend highly on the owner’s driving habits, record-keeping methods, fuel quality, and more. While observing increased fuel economy is extremely common after installing a FASS Fuel System, we cannot guarantee a measurable MPG improvement.


Have questions about a FASS Diesel Fuel System for your Duramax, Powerstroke, or Cummins-powered truck? Contact us today!


We’re proud to be a family-owned, U.S.-based manufacturer. From our production facility in Marthasville, Missouri, we serve diesel owners around the world.

What is a FASS Diesel Fuel Systems No-Drop Kit_Blog Image
By Jake H December 8, 2025
What is a FASS No-Drop Kit? It’s a FASS Diesel Fuel System that includes a Fuel Sump for quick installation and consistent fuel delivery—no tank drop required.
Why your STOCK diesel truck benefits from a FASS Fuel System_Blog Image
By Jake H December 5, 2025
Upgrade to FASS and enjoy 3× injector life, smoother performance, and unmatched 2-micron filtration for your class 8 truck, pickup, or diesel-powered equipment!