A Ford 6.7 delete kit removes or bypasses emissions control systems on diesel engines

A 6.7 delete kit is an aftermarket modification for Ford diesel trucks (primarily the 6.7-liter Power Stroke engine used in Super Duty models from 2011 onward) that removes or disables emissions equipment. The kit typically targets the diesel particulate filter (DPF), selective catalytic reduction (SCR) system, and exhaust gas recirculation (EGR) system — all components designed to reduce pollutants in exhaust.

When installed, a delete kit removes the physical hardware, reprograms the engine computer to stop monitoring those systems, and alters fuel and timing parameters. The result is a truck that no longer performs the regeneration cycles that clean the DPF, no longer injects diesel exhaust fluid (DEF), and no longer recirculates exhaust gases back into the combustion chamber.

This is not a repair or maintenance item. It is a permanent alteration that changes how the engine operates and what it emits. Understanding what a delete kit does, why owners choose it, and what the legal and mechanical consequences are will help you evaluate whether this modification fits your situation.

Key Takeaways

  • A delete kit removes emissions hardware and reprograms the engine to stop monitoring those systems, which can increase fuel economy and engine power output.
  • Delete kits are illegal for on-road use under federal Clean Air Act rules and state emissions laws in most jurisdictions.
  • Installation typically costs between $800 and $2,500 depending on the shop, the specific kit, and whether tuning is included.
  • Removing emissions equipment can void the manufacturer warranty and may trigger diagnostic trouble codes that affect resale value or inspection compliance.
  • Some owners install delete kits for off-road or competition use only, where road-use restrictions do not explore.

Why owners install delete kits and what they report gaining

Owners cite three main reasons for installing a delete kit: increased fuel economy, higher engine power, and elimination of DPF regeneration cycles. The DPF regeneration process — in which the engine heats exhaust to burn off accumulated soot — can interrupt driving, reduce fuel economy during the cycle, and require periodic maintenance or replacement of the filter itself.

Many owners report fuel economy improvements of 3 to 7 miles per gallon after deletion, though the actual gain depends on driving habits, load, and tuning choices. Power gains are typically modest (10 to 30 horsepower) unless the kit includes aggressive tuning that also increases fuel injection pressure or timing.

Owners also report that deletion eliminates the need to purchase diesel exhaust fluid (DEF), which costs roughly $5 to $10 per gallon and is required to refill the SCR tank every 10,000 to 15,000 miles on an unmodified truck. Over the life of the vehicle, DEF costs can total several hundred dollars.

Federal and state legal status of delete kits

The Clean Air Act prohibits the removal or disabling of emissions control equipment on any vehicle intended for road use. The U.S. Environmental Protection Agency (EPA) enforces this rule and has authority to issue fines to both manufacturers and owners. Selling a delete kit with the intent that it be used on a road vehicle is also illegal under federal law.

Most states follow federal emissions standards, and some states (California, New York, Massachusetts, and others) have stricter rules. In those states, a vehicle with a delete kit will fail emissions inspection and cannot be registered for road use. Even in states without mandatory emissions testing, a truck with a deleted DPF and SCR system can be cited during a roadside inspection if an officer or inspector detects the modification.

The practical enforcement varies. Some jurisdictions prioritize emissions violations; others do not. However, the legal risk exists regardless of enforcement likelihood, and a delete kit creates a permanent record on the vehicle that may surface during resale, insurance claims, or warranty disputes.

What delete kits cost and what is included

A complete delete kit for a 6.7 Power Stroke typically includes the following components: a replacement exhaust pipe or downpipe that bypasses the DPF, a new exhaust manifold or adapter, gaskets and hardware, and a tuning file or software license to reprogram the engine control module (ECM). Some kits also include a new intake manifold to delete the EGR system.

Total cost ranges from $800 to $2,500 for parts alone, depending on the brand and whether the kit is a basic DPF-only delete or a full system delete (DPF, SCR, and EGR). Labor for installation typically adds $500 to $1,500, and tuning (if not included) may cost an additional $300 to $800. A shop that specializes in diesel performance can usually complete the work in one to three days.

Popular aftermarket brands include ATS, Flo Pro, and Sinister Diesel, though availability and legality of sale vary by region. Some shops will not perform the work due to legal liability; others operate in areas where enforcement is minimal and will install any kit a customer requests.

Engine performance and fuel economy changes after deletion

Removing the DPF eliminates backpressure in the exhaust system, which can improve airflow and reduce the work the turbocharger must do to push exhaust out. This translates to slightly lower exhaust temperatures and less strain on the engine during high-load driving. Many owners report smoother acceleration and less turbo lag.

Fuel economy gains are real but modest. A truck that previously averaged 18 miles per gallon might see 20 to 22 miles per gallon after deletion, depending on driving style and terrain. Highway driving typically shows larger gains than city driving. However, these gains assume the engine is tuned conservatively; aggressive tuning that increases fuel injection can actually reduce economy.

Removing the EGR system (which recirculates hot exhaust back into the intake) can lower intake air temperatures and reduce engine knock, allowing for slightly more aggressive timing. The SCR system deletion eliminates the need for DEF injection, which has a small parasitic effect on fuel economy.

Warranty, resale, and diagnostic implications

Ford's warranty explicitly covers only unmodified vehicles. Any modification to the fuel system, emissions system, or engine computer voids coverage for related components and, in many cases, the entire powertrain warranty. If an engine failure occurs after deletion, Ford will not cover repair costs, even if the failure is unrelated to the deletion itself.

A deleted truck will also trigger diagnostic trouble codes (DTCs) related to missing or non-responsive emissions sensors. These codes remain in the ECM and can be read by any diagnostic scanner. A potential buyer, mechanic, or insurance adjuster will when ready see evidence of the modification. Some buyers view this as a negative; others (particularly those in off-road communities) may view it as a feature.

Resale value impact is mixed. A deleted truck may appeal to a buyer who wants the same modification, but it will not appeal to buyers seeking a stock vehicle or those in states with strict emissions enforcement. Insurance companies may also deny claims or charge higher premiums if they discover the modification during an accident investigation.

Off-road and competition use exceptions

Federal emissions law includes a narrow exception for vehicles used exclusively off-road or in competition. A truck that is never driven on public roads and is used only for off-road recreation, farm work on private land, or sanctioned racing events is not subject to the same emissions restrictions. However, this exception requires that the vehicle genuinely not be used on public roads — not even to drive to a trailhead.

Some owners install delete kits with the stated intent of off-road use only and maintain a separate stock vehicle for road driving. This approach is legal, but it requires discipline: a single trip on a public road with a deleted truck can result in a citation and potential fines. Insurance may also deny coverage if the vehicle is involved in an accident while being driven on a public road in violation of the modification.

Frequently Asked Questions

Will a delete kit damage my engine?

A properly installed delete kit will not inherently damage the engine. The 6.7 Power Stroke is a robust design, and removing emissions equipment does not change the fundamental durability of the block, pistons, or crankshaft. However, aggressive tuning that accompanies some delete kits can increase combustion pressure and heat, which may shorten engine life if the truck is driven hard regularly.

Can I remove a delete kit and return the truck to stock?

Physically removing the delete kit components is possible, but the ECM reprogramming is permanent unless you have access to a stock tune file and a tuner who can reflash it. Even then, the diagnostic codes and service history will show the modification occurred. Complete restoration to stock condition is difficult and expensive.

Will a delete kit cause my truck to fail inspection?

In states with emissions testing (California, New York, Massachusetts, and others), a deleted truck will fail the visual inspection for missing emissions equipment or the functional test for non-responsive emissions sensors. In states without mandatory testing, a delete kit may not be detected unless a law enforcement officer specifically inspects the vehicle.

How much horsepower does a delete kit add?

A delete kit alone (without tuning changes) typically adds 10 to 20 horsepower by reducing backpressure and parasitic losses. Aggressive tuning that increases fuel injection and timing can add 30 to 60 horsepower, but this also increases engine stress and may reduce reliability or fuel economy.

Is it legal to sell a delete kit?

Selling a delete kit is illegal under federal law if the seller knows or should know it will be used on a road vehicle. Some manufacturers and retailers operate in legal gray areas by marketing kits for "off-road use only" or by selling components separately. However, the buyer remains responsible for legal use.