Few vehicles, if any, are as much fun as a rowdy diesel truck. The sound, the power, the speed—it's addicting.
That said, everything has a cost. And when you start adding horsepower to a Cummins, Duramax, or Powerstroke, said cost can get out of hand really fast if you're not planning ahead!
That said, our team here at FASS Motorsports is made up of die-hard diesel enthusiasts—we live and breath fast trucks. So, we thought we'd share some insight from our own experiences; and maybe save you a headache or two.
Fuel Delivery: The Foundation of Power
One of the first roadblocks diesel owners hit is the fuel system. Stock lift pumps and filters were never designed for big injectors or aggressive tuning. Starving the injection pump leads to low rail pressure, injector damage, and even catastrophic pump failure.
Solution: Upgrade to a FASS Diesel Fuel System! With 2-micron filtration, water separation, and air/vapor removal, FASS provides FAR better filtration and flow than stock—ensuring your high-performance setup has consistent, clean fuel.
This protects injectors, extends pump life, and provides the flow needed for higher horsepower builds.
Transmission Strain
The torque that a modified Cummins, Powerstroke, or Duramax can generate is brutal on transmissions. Even a modest tune can can drastically shorten the life of your transmission—especially with aggressive driving.
Many truck owners quickly realize that horsepower is easy to add—keeping the transmission alive is the hard part!
Solution: Budget for transmission upgrades early! Whether it’s a valve body, torque converter, or full build, a healthy transmission is key to putting power to the ground.
Turbo Lag and Driveability
Bigger turbos mean more airflow and higher horsepower potential, but they can also create lag. A setup that shines on the dyno may feel sluggish on the street if not matched properly with injectors and tuning.
Solution: Do your homework before buying—ask other owners, check out Facebook groups, and see what online reviews say.
Depending on your horsepower goals, a compound turbo kit or well-matched single turbo will give the best of both worlds—strong top-end power with street-friendly spool-up!
Cooling and EGT Control
More fuel and boost equals more heat. Exhaust Gas Temperatures (EGTs) can skyrocket under load, risking engine damage if not controlled. Stock intercoolers, radiators, and exhaust systems often can’t keep up with higher output builds.
Solution: Invest in upgraded intercoolers, high-performance radiators, and proper tuning. Also, monitoring EGTs with a quality gauge is critical, especially when towing or running aggressive tunes.
Legal and Reliability Considerations
It’s also worth noting that some modifications may affect emissions compliance (on trucks built after 2007) and factory warranties. Additionally, aggressive tuning without supporting mods will often lead to reliability problems that cost more in the long run.
Make no mistake; tampering with, disabling, and/or removing emissions components is federally illegal—period. While your state or local laws may not specifically ban such practices, the EPA and DOJ are still (as of October 2025) actively pursuing both civil and criminal cases for such modifications.
Solution: Plan your build. Decide whether your truck will be a daily driver, dedicated tow rig, or competition build—and choose parts that match your goals. This keeps your truck reliable while delivering the performance you want.
If you own a diesel truck built after 2007, understand the legal and financial risks associated with emissions-system tampering.
Work With Experts Who Understand Diesel Performance
At FASS Motorsports, we live and breathe diesel performance. From fuel systems and turbo kits to transmissions, suspension, and wheels, our team in Washington, Missouri has helped countless truck owners in Franklin County and the greater St. Louis area build reliable horsepower.
Please Note: We do not sell, promote, or install emissions-defeat devices of any kind. Please do not contact us for related parts or services—we will not be able to help.
If you’re ready to start upgrading your diesel, don’t just throw parts at it. Let’s build a plan that makes sense—so your truck stays strong, powerful, and ready for whatever you throw at it.
Questions? We’re Here to Help.
Not sure which performance parts are right for your diesel? Contact FASS Motorsports and we’ll get you dialed:
- Phone: 636-429-7020
- Email: info@fassmotorsports.com