6.7 Powerstroke Deleted vs. Stock: Performance, MPG, Risks

A deleted 6.7 Powerstroke engine generally offers increased horsepower, torque, and fuel efficiency due to the removal of restrictive emissions components like the DPF and EGR, while a stock engine maintains emissions compliance and a cleaner exhaust. Deleting a truck results in higher performance but is illegal and may have other consequences, such as increased soot production in the exhaust and potential engine lifespan changes.

If you own a Ford Super Duty with the 6.7L Powerstroke diesel, you’ve likely heard the whispers at the job site or on the forums. Some owners swear that "deleting" the truck turns it into an unkillable, fuel-sipping beast. Others warn of federal fines, voided warranties, and resale nightmares.

So, who is right?

The debate of 6.7 Powerstroke deleted vs. stock isn't just about horsepower—it's about weighing the longevity of your engine against the legality of your registration. Below, we break down the real-world data on MPG, reliability, and performance to help you decide if the risk is worth the reward.

What Does "Deleting" a 6.7 Powerstroke Actually Mean?

Before we dive into the stats, let’s clarify what happens during a delete. "Deleting" a modern diesel truck involves physically removing the emissions control systems mandated by the EPA. On a 6.7 Powerstroke, this typically targets 3 components:

• EGR (Exhaust Gas Recirculation): Recirculates exhaust back into the intake to lower combustion temperatures. It is a notorious source of carbon buildup (soot) in the engine.
• DPF (Diesel Particulate Filter): A filter in the exhaust that traps soot. It requires "regen" cycles (dumping raw fuel into the exhaust) to burn off the soot, which hurts fuel economy.
• DEF (Diesel Exhaust Fluid): The fluid injected into the exhaust to reduce Nitrogen Oxide (NOx) emissions.

Once these physical parts are removed, the truck’s ECU (computer) must be tuned to stop looking for sensors that no longer exist. Without this tune, the truck would go into "limp mode."

The Case for Keeping It Stock (Pros & Cons)

For the vast majority of owners—especially those with newer trucks under warranty—keeping the truck stock is the smartest financial move.

The Pros of Stock:

• Warranty Protection: The 6.7 Powerstroke powertrain warranty (5 years/100,000 miles) is valuable. Deleting immediately voids this.
• Legal Compliance: You can drive through any state, pass any smog check, and trade it in at any dealership without hassle.
• Quiet & Clean: No "rolling coal," no raw diesel smell, and a whisper-quiet cabin.

The Cons of Stock:

• Reliability Anxiety: The emissions systems (specifically the EGR cooler and DPF sensors) are the most common failure points on modern diesels.
• MPG Penalties: During "regen" cycles, your fuel economy can drop drastically as the truck uses diesel to clean the filter rather than move the wheels.

Comparing 6.7 Powerstroke Deleted vs. Stock 

To help you visualize the trade-offs, here is a direct comparison of how a stock 6.7L Powerstroke stacks up against a deleted counterpart across the four most critical categories.

You can watch this video to learn about the different sounds of stock and deleted 6.7L Powerstroke engines:

1. Performance: Restrained vs. Unleashed

Stock: Out of the factory, the 6.7 Powerstroke is a marvel of engineering, delivering massive torque (up to 1,050 lb-ft on newer High Output models). However, the exhaust system is highly restrictive due to the DPF and catalytic converters. This creates backpressure that results in noticeable "turbo lag" and a muted throttle response.

Deleted: When you remove the DPF and EGR restrictions, you reduce exhaust backpressure to almost zero. Combined with an ECU tune, this typically unlocks an immediate 50–100 additional horsepower. The most noticeable difference isn't just peak speed—it is the throttle response. The turbo spools instantly, making the truck feel significantly lighter and more responsive.

2. Fuel Economy: The MPG Reality Check

Stock: A stock truck is forced to enter "Regeneration Mode" (Regen) periodically to burn off soot trapped in the DPF. During regen, the truck injects extra fuel into the exhaust stroke, effectively wasting diesel to clean the filter. This process drags down your overall average to roughly 13–16 MPG combined.

Deleted: By physically removing the DPF, you eliminate the need for regen cycles entirely. Without the computer dumping fuel into the exhaust, and with the engine breathing easier, owners consistently report gains of 20–30% in fuel efficiency. It is not uncommon to see highway numbers hit 19–21 MPG on a deleted single-rear-wheel (SRW) truck.

3. Legal and Environmental Considerations

Stock: A stock truck is compliant with the Clean Air Act and meets strict EPA standards for Nitrogen Oxide (NOx) and particulate matter. You can legally drive, sell, and register this truck in all 50 states.

Deleted: This is the biggest hurdle. Deleting a truck is a violation of federal law. While enforcement is primarily targeted at shops selling the kits, individual owners in states with emissions testing (like California, Colorado, or New York) will fail inspections immediately. Furthermore, deleted trucks emit visibly darker exhaust ("rolling coal") if tuned improperly, which draws negative attention and potential fines.

4. Maintenance and Longevity

Stock: Maintenance involves regular refills of Diesel Exhaust Fluid (DEF) and eventual service of the DPF system, which can cost upwards of $3,000 to replace if it clogs. However, the stock tuning is designed to keep cylinder pressures within safe limits, protecting head gaskets.

Deleted: A deleted engine runs cleaner internally. By removing the EGR (Exhaust Gas Recirculation), you stop abrasive soot from being fed back into your engine's intake, which keeps your oil cleaner for longer and extends the life of internal bearings. The downside? If you run a "hot" tune (high HP) on a deleted truck, you risk blowing head gaskets or damaging the transmission, as the stock components weren't built for that extra stress.

The Dark Side: Legal, Warranty, and Financial Risks

You cannot talk about deleting without addressing the elephant in the room: It is federally illegal in the United States.

1. The EPA and Legality

Under the Clean Air Act, tampering with emissions devices is a federal offense. While the EPA historically targeted manufacturers and large shops (handing out millions in fines), individual enforcement varies by state.

• Strict States: If you live in California, Colorado, or strict counties in the Northeast, you will fail inspection. You cannot register the truck.
• "Free" States: In states without emissions testing, you might drive daily without issues, but it remains federally illegal.

2. Warranty & Insurance Nightmares

Warranty: If you blow a turbo or spin a bearing on a deleted truck, Ford will deny the claim. You are effectively your own warranty station.

Insurance: In the event of an accident, some insurance adjusters look for modifications. If they determine the delete (and subsequent HP increase) contributed to the accident, they could theoretically deny coverage.

3. Resale Value: The Split Market

• Dealerships: Most franchise dealerships (Ford, Chevy, Ram) will not accept a deleted truck on trade-in because they cannot legally resell it without spending thousands to restore it to stock.
• Private Party: Ironically, deleted trucks often command a premium in the private market among enthusiasts who want a pre-modified, "reliable" rig. However, your pool of buyers is limited to cash buyers or those in non-testing states.

Model Year Nuances: 2011–2016 vs. 2017+ Alumiduty

Not all 6.7 Powerstrokes are created equal when it comes to deleting.

• 2011–2014 (Early Gen): These have a problematic ceramic ball bearing turbo. Deleting often helps preserve this turbo, but these trucks are aging.
• 2015–2016: Improved turbo design. Very popular candidates for deletion.
• 2017–2019 (Alumiduty): The sweet spot. The aluminum body reduces weight, and the engine is robust. Deleting these turns them into absolute rockets.
• 2020+ Models: Ford changed the game with a steel piston design and a more complex dual-cooler EGR system. Deleting these is significantly more expensive and complex due to the sophisticated ECU encryption and transmission tuning required for the 10-speed transmission.

Spetuner all-in-one 6.7 powerstroke delete kit combines EGR delete, DPF delete, and tuner solutions into one powerful package for your 6.7L diesel delete.

Should You Delete Your 6.7 Powerstroke?

Keep it Stock IF:

• You have a factory warranty remaining.
• You live in an area with emissions testing.
• You plan to trade the vehicle in at a dealership within 3 years.
• You run a commercial DOT-regulated fleet (DOT officers check for deletes).

Consider Deleting IF:

• The truck is out of warranty.
• You plan to keep the truck "until the wheels fall off" (300k+ miles).
• You use the truck exclusively for off-road work, farming, or ranching.
• You are prepared to pay cash for any major engine repairs.

FAQs

How much MPG does deleting a 6.7 Powerstroke add?

Most owners see an increase of 2 to 5 MPG during highway driving. Towing MPG sees a smaller improvement, typically 1–2 MPG, but the engine runs cooler.

Does deleting a 6.7 Powerstroke make it reliable?

Mechanically, yes. By removing the EGR and DPF, you eliminate the most common failure points and stop soot from recirculating into the engine oil. However, it introduces legal unreliability regarding registration and resale.

Can I trade in a deleted truck?

Most major dealerships will not accept a deleted truck or will offer you a "wholesale" price significantly below market value (auction price). You are usually better off selling it privately.

Is it illegal to delete a diesel truck in all states?

Yes. Tampering with emissions control systems is a violation of Federal law (Clean Air Act), regardless of whether your specific state or county requires emissions inspections.

Disclaimer: This article is for educational and informational purposes only. We do not condone or encourage the removal of emissions equipment on vehicles used on public highways. Always check your local laws and regulations.