Why Towing 20+ Tons Demands More From Your Diesel

Towing loads exceeding 20 tons—whether it’s heavy equipment, a fifth-wheel RV, or a livestock trailer—pushes a pickup’s chassis, brakes, and drivetrain to their limits. For Cummins-equipped trucks, the engine itself is capable of immense torque, but modern emissions controls can strangle that potential. In stock form, a 6.7L Cummins ISB produces around 900 lb‑ft of torque; with a delete kit and proper tuning, those numbers often climb past 1,100 lb‑ft, and some builds reach 1,300 lb‑ft or more. That extra twist translates directly into easier hill climbs, less gear hunting, and lower EGTs under heavy load. This article expands on how a Cummins delete kit can let you safely tow 20+ tons while keeping engine temperatures and fuel economy in check.

Understanding Cummins Delete Kits

A Cummins delete kit removes or disables emissions control components: the exhaust gas recirculation (EGR) system, diesel particulate filter (DPF), and selective catalytic reduction (SCR) system. While these systems are required for on-road operation, they create significant back-pressure, increase under-hood temperatures, and reduce fuel efficiency. For dedicated tow trucks used off-highway or in regions with no emissions testing, a delete kit unlocks the engine’s true capability.

The Science Behind Power Gains

EGR Delete

The EGR system routes exhaust gas back into the intake to lower combustion temperatures and reduce NOx. That exhaust is hot and dirty; it cakes intake valves with soot, reduces throttle response, and raises intake air temperatures. Deleting the EGR system cleans up the intake charge, lowers IATs, and allows the turbocharger to operate more efficiently. The result is a measurable increase in air density entering the cylinders, which supports more fuel and more power without exceeding safe exhaust gas temperatures.

DPF and SCR Delete

The DPF traps soot particles and requires periodic regeneration, which injects extra fuel to raise exhaust temperatures and burn off the soot. This process wastes fuel and adds heat stress to the engine. The SCR system requires diesel exhaust fluid (DEF) and adds further back-pressure. Removing both the DPF and SCR with a delete pipe (often called a “straight pipe” or “turbo-back exhaust”) reduces exhaust restriction dramatically. On a 6.7L Cummins, this alone can free up 30–50 horsepower and 60–80 lb‑ft of torque at the wheels. The turbo also spools quicker, improving transient response when you’re pulling away from a stop with a heavy trailer.

Tuning and ECM Recalibration

A delete kit is only half the equation. The engine control module (ECM) must be reprogrammed to disable the deleted systems and to optimize fuel timing, rail pressure, boost limits, and torque management. Popular tuning platforms include EFILive, PPEI, and EZ Lynk. Custom tuning tailored to your specific truck and typical load weight yields the safest and most effective results. Tunes that prioritize towing often increase low-end torque while keeping peak cylinder pressures within safe limits.

Safety Considerations When Towing 20+ Tons

Adding power is exciting, but towing 40,000+ pounds demands thorough preparation beyond the engine. A delete kit alone does not make a truck safe for extreme towing.

Braking and Exhaust Brake

Stopping 20+ tons requires brakes that can handle the heat. Stock brakes on a one-ton dually will work, but they can fade on steep grades. An exhaust brake or aftermarket auxiliary braking system becomes essential. Many 6.7L Cummins trucks come with a VGT turbo that can be tuned to act as an air brake; delete kits and tuning can actually improve exhaust brake performance because there is no DPF to dampen the back-pressure. For maximum control, consider upgrading to larger rotors, carbon‑ceramic pads, or a driveline brake.

Coolant and Transmission Temperatures

Under sustained heavy load, coolant and transmission oil temperatures climb quickly. The delete kit reduces engine heat rejection because lower back-pressure means the engine doesn’t have to work as hard, but that benefit can be offset by the increased power output. Install a coolant temperature gauge, transmission temperature gauge, and EGT gauge (pyrometer) before and after the delete. If you plan to tow 20+ tons regularly, upgrading the cooling system (larger radiator, high-flow water pump, auxiliary transmission cooler) is a wise investment. Many owners report that a deleted and tuned 6.7L Cummins actually runs cooler with moderate towing loads than a stock truck does, because the engine is not fighting the DPF regeneration cycle.

Suspension and Tire Ratings

Towing 40,000 pounds gross combined weight (GCWR) requires a truck that can handle the payload. Verify your truck’s gross vehicle weight rating (GVWR) and combined weight rating are not exceeded. Overloaded tires and leaf springs can cause catastrophic failure. Replace old tires with load range G or higher, and consider air bags or supplemental spring packs to level the truck and reduce sway. Proper weight distribution and a stout fifth‑wheel or gooseneck hitch are non‑negotiable.

Choosing the Right Delete Kit

Not all delete kits are created equal. The best kit for towing heavy loads prioritizes flow without compromising structural integrity.

Full vs. Partial Delete Kits

Full kits include an EGR delete plate or cooler block-off, a DPF-back exhaust system (often 4″ or 5″ stainless steel), and a downpipe that replaces the restrictive factory unit. Partial kits may only remove the DPF and tune out the EGR without physically removing it. For maximum performance and reliability, a full delete is recommended. The EGR cooler is prone to failure, and leaving it in place risks coolant leaks into the intake. A full delete eliminates that failure point.

Brand Selection and Compatibility

Stick with reputable brands that supply the heavy-towing aftermarket: Fleece Performance Engineering, PPEI, Sinister Diesel, and H&S Motorsports (for older trucks). Confirm the kit matches your engine year and chassis. The 5.9L (L-B and later common-rail) and 6.7L (ISB) have different configurations. A 2013–2018 6.7L delete kit differs from a 2019+ model due to emissions hardware changes.

In the United States, the Clean Air Act prohibits tampering with emissions controls for on-road use. Delete kits are sold “for off-road use only.” If your truck is registered and driven on public roads, you are legally required to retain all emissions equipment. Many states also enforce visual inspections or OBD‑II readiness tests that will fail if emissions monitors are disabled. Know your local laws before proceeding. If you only tow on private property or in areas without inspections, an off-road delete is permissible, but expect to keep documentation of your truck’s operational status.

Installation Tips for Delete Kits

Installing a delete kit is an intermediate-to-advanced DIY job, but many owners choose professional installation to avoid mistakes. The process typically takes 6–12 hours. Key steps include:

  • Disconnect the batteries and allow the engine to cool completely.
  • Remove the DPF and DEF components – these are heavy and may require a transmission jack or helper.
  • Remove the EGR cooler and valve – on 6.7L trucks, the EGR cooler is under the turbo. Use new gaskets and O-rings.
  • Install the delete downpipe – ensure it clears the transmission cooler lines and cab mounts.
  • Assemble the exhaust system – clamp or weld, depending on the kit. Avoid leaks at V-bands.
  • Reprogram the ECM – using a tuning device, load the correct calibration file for your truck and delete kit. Do not skip this step; running a deleted truck without tuning will cause check engine lights, limp mode, and potential turbocharger overspeed.

Common pitfalls: overtightening bolts on aluminum parts (EGR cooler block-off), failing to plug vacuum lines if the kit deletes EGR valve actuation, and not updating the transmission tuning (for 68RFE or Aisin transmissions) to handle the higher torque. If your truck has an automatic, always pair a transmission tune with the engine tune to prevents harsh shifts and overheating.

Testing Your Setup Before Heavy Towing

After installation and tuning, test the truck incrementally. Start with a short drive with no trailer to verify no boost leaks, no coolant leaks, and no abnormal smoke. Check for DTCs with a scan tool. Then attach a trailer weighing around 10 tons and take a test route that includes a moderate grade. Monitor EGTs, boost pressure, coolant temperature, and transmission temperature. Ensure the exhaust brake functions as expected. Once you’re satisfied, you can proceed to your maximum 20+ ton load. A data-logger (like the Edge Insight CTS3 or a Banks iDash) provides real-time info and can log runs for tuning refinement.

Maintenance Considerations After Deleting

A deleted and tuned Cummins demands more disciplined maintenance. Oil change intervals should not exceed 5,000 miles because the higher EGTs can shear oil viscosity. Use a heavy-duty diesel oil (CJ‑4 or CK‑4) with a high TBN. Fuel quality is also critical – poor fuel can cause injector sticking or over-fueling. Keep a spare set of boost and EGT sensors because higher power levels can shorten their lifespan. Inspect the exhaust system annually for cracks at welds or hangers, especially if you tow off-road on rough terrain.

Real-World Towing Performance

Owners of deleted Cummins trucks report towing 20–28 tons (fifth-wheel and gooseneck trailers) with significantly lower fuel consumption and less driver fatigue. For example, a 2015 Ram 3500 with a 6.7L Cummins, 4″ turbo-back exhaust, EGR delete, and a PPEI tow tune will typically see 12–14 mpg unloaded and 8–10 mpg towing 25,000 pounds on flat highway. Stock, those figures are closer to 10–11 mpg unloaded and 6–7 mpg towing. More importantly, the deleted truck maintains highway speed on 6% grades without downshifting, whereas a stock truck will drop to 55–60 mph and require frequent throttle inputs. The reduced engine stress from lower EGTs and no DPF regens adds confidence during hour-long climbs. For more first-hand data, consult communities like Cummins Forum or tuning-specific resources such as EZ Lynk and PPEI.

Conclusion

Cummins delete kits and proper tuning allow you to safely tow 20+ tons with improved power, torque, and fuel efficiency. By removing restrictive emissions equipment and optimizing the ECM, the engine reaches its full potential without sacrificing reliability. However, safety requires more than just a powerful engine: choose a quality kit, ensure professional installation or careful self-installation, upgrade your brakes and cooling system as needed, and never exceed your truck’s structural or tire ratings. With the right preparation, your deleted Cummins will deliver miles of confident towing under the heaviest loads.