A DPF delete kit removes or disables your truck's diesel particulate filter system
A DPF delete kit for a 2020 Ram 2500 6.7L removes the diesel particulate filter (DPF) from your exhaust system and reprograms your engine computer to stop monitoring it. The DPF is a factory emissions control device that traps soot and ash from diesel combustion. Deleting it increases engine power and fuel economy, but it also makes your truck illegal to drive on public roads in all 50 states and voids your manufacturer warranty.
The 2020 Ram 2500 6.7L Cummins diesel comes with a DPF as standard equipment. Aftermarket delete kits physically remove the filter and install a straight pipe in its place, then use a tuner to reprogram the engine control module (ECM) so it no longer expects DPF sensor data. Without the reprogramming, your truck will throw diagnostic trouble codes and go into limp mode.
Key Takeaways
- DPF delete kits are illegal for on-road use under the Clean Air Act, and using one can result in fines up to $37,500 per vehicle from the EPA.
- Deleting the DPF typically adds 50 to 100 horsepower and improves fuel economy by 3 to 5 miles per gallon, but these gains come with legal and mechanical trade-offs.
- Your Ram 2500 6.7L warranty is void once a delete kit is installed, and Cummins dealers will refuse warranty work on engine and emissions components.
- Diesel particulate filters require periodic regeneration cycles; deleting the system eliminates this maintenance but removes a layer of engine protection.
- Off-road use of a deleted truck is legal in most states, but selling a truck with a delete kit installed can expose you to liability if the buyer is caught driving it on public roads.
How a DPF delete kit physically works on the 6.7L Cummins
The delete kit includes a replacement exhaust pipe that bypasses the DPF canister entirely. On the 2020 Ram 2500, the DPF sits between the turbocharger outlet and the muffler. The kit removes this section and installs a straight pipe, which reduces backpressure and allows exhaust gases to flow more freely to the atmosphere.
The physical removal alone is not enough. The engine computer continuously monitors DPF pressure, temperature, and regeneration cycles. Without a tuner that disables these sensors and removes the DPF logic from the ECM, your truck will store fault codes P0401 (EGR flow insufficient) and P0471 (exhaust pressure sensor range/performance) within minutes of startup. The check engine light stays on, and the truck may enter reduced power mode.
Most delete kits for the 2020 6.7L come bundled with a tuning device or require a separate ECM tune from companies like EFILive, Smarty, or H&S Performance. The tuner connects to your OBD-II port, reads the factory calibration, removes DPF-related code, and writes the modified file back to the ECM. This process takes 30 to 60 minutes and is permanent until you reflash the truck back to stock.
Legal consequences and EPA enforcement
The Clean Air Act prohibits removing, disabling, or rendering inoperative any emissions control device on a vehicle intended for on-road use. The EPA and state environmental agencies enforce this rule through roadside inspections, emissions testing, and dealer reports. Penalties for individuals caught with a deleted truck range from $2,500 to $37,500 per vehicle, depending on the state and whether it is a first or repeat offense.
Manufacturers and shops that sell delete kits face separate liability. The EPA has issued consent decrees against companies like Diesel Injection Services and others for selling defeat devices. Shops that install deletes can be fined and lose their ASE certifications. Some states, including California, have additional penalties and may impound the vehicle.
Enforcement is inconsistent. Some states conduct regular emissions testing and visual inspections at registration renewal; others do not. However, the legal risk exists regardless of enforcement likelihood. Insurance companies may deny claims if they discover a deleted truck was involved in an accident, and some policies explicitly exclude coverage for modified emissions systems.
Performance gains and fuel economy trade-offs
A deleted 2020 Ram 2500 6.7L typically gains 50 to 100 horsepower and 100 to 150 pound-feet of torque, depending on the tuner used and whether other modifications are present. This comes from two sources: reduced backpressure from the straight pipe and the removal of DPF regeneration cycles, which normally consume fuel and engine resources.
Fuel economy improvements range from 3 to 5 miles per gallon under normal driving. Towing and heavy load scenarios show smaller gains because the engine is already working near its limit. Some owners report 2 to 3 mpg improvement when towing, while others see no change.
These gains come with hidden costs. Without the DPF, unburned soot and particulates exit directly into the atmosphere. Engine oil accumulates more soot over time because the DPF normally traps it before it can enter the crankcase. Oil change intervals may need to shorten from 15,000 miles to 10,000 miles or less, offsetting fuel savings. Turbocharger life may also shorten due to increased exhaust temperatures and soot load.
Warranty implications and dealer service
Cummins and Ram void the entire powertrain warranty once a DPF delete is detected. Dealers can identify a deleted truck through a straightforward ECM scan; the absence of DPF sensor data and the presence of modified calibration code are when ready red flags. Warranty denial applies to the engine, transmission, turbocharger, and all emissions-related components.
This means any engine failure, turbo failure, or transmission issue after deletion is your responsibility to repair, even if the failure is unrelated to the delete itself. A Cummins 6.7L engine rebuild can cost $4,000 to $8,000 in parts and labor. Turbocharger replacement runs $1,500 to $3,000. These costs fall entirely on the owner once the warranty is void.
Some independent diesel shops will service a deleted truck, but they cannot perform warranty work. You will need to find a shop willing to work on modified engines, and labor rates may be higher because the shop assumes liability for any issues that arise.
DPF regeneration and what happens without it
The factory DPF on the 2020 6.7L undergoes active regeneration cycles, where the engine heats exhaust to 600+ degrees Fahrenheit to burn off trapped soot. This happens automatically during highway driving and can be triggered manually through the truck's diagnostic menu. Regeneration cycles consume fuel and add heat to the engine, but they prevent DPF clogging and maintain engine efficiency.
Without a DPF, regeneration no longer occurs. Soot that would have been trapped instead enters the engine oil and atmosphere. Over time, this can lead to oil sludge buildup, increased wear on piston rings and cylinder walls, and higher particulate emissions. The engine runs hotter because there is no backpressure regulation from the DPF.
Some owners report that deleted trucks run hotter under load, which can shorten engine life if cooling system maintenance is neglected. Keeping coolant fresh and ensuring the radiator is clean becomes more critical on a deleted engine.
Off-road use and private property considerations
Using a deleted truck exclusively off-road or on private property is legal in most states. The Clean Air Act applies to vehicles "intended for use" on public roads. If your truck never leaves private land, enforcement is unlikely. However, this distinction is difficult to prove if you are caught, and some states have closed this loophole through additional regulations.
If you plan to use a deleted truck only for off-road work, farm use, or private land, document this clearly. Keep records of where the truck is stored, who has access to it, and what it is used for. Do not register it for on-road use, and do not drive it on public roads, even briefly.
Selling a truck with a delete kit installed transfers liability to the buyer. If the new owner drives it on public roads and is caught, you could face legal questions about whether you knowingly sold a non-compliant vehicle. Some states treat this as a violation of consumer protection laws. It is safer to reflash the truck back to stock before selling it, even if you lose the performance gains.
Frequently Asked Questions
Can I get caught with a DPF delete during a regular traffic stop?
A police officer cannot tell a truck is deleted just by looking at it. However, if you are pulled over for another reason and the officer requests an emissions inspection or runs a diagnostic scan, a deleted truck will fail. Some states conduct random roadside emissions testing at inspection stations. The risk depends on your state's enforcement level.
Will a delete kit damage my engine if I keep it installed long-term?
A deleted 6.7L can run reliably for years, but soot accumulation in the oil and higher operating temperatures increase wear over time. Shorter oil change intervals and diligent maintenance can mitigate this. However, you are accepting higher long-term engine wear compared to a stock truck.
Can I reflash my truck back to stock and remove the delete?
Yes. If you have the original factory calibration file, a tuner can reflash your ECM back to stock. The physical DPF pipe must be reinstalled, which requires removing the straight pipe and bolting the original DPF assembly back in place. This is reversible but takes time and money.
What is the difference between a DPF delete and a DPF delete tune?
A DPF delete is the physical removal of the filter and installation of a straight pipe. A DPF delete tune is the ECM reprogramming that disables DPF monitoring. You need both for the truck to run properly. Some kits bundle them together; others require separate purchases.
Will a deleted truck pass a smog check or emissions test?
No. A deleted truck will fail any emissions test that includes an OBD-II scan or tailpipe particulate measurement. Some states only test OBD codes; others measure actual emissions. Either way, a deleted truck cannot pass.