How Much HP Do You Gain from Deleting a 6.7 Cummins?

The term 'delete' gets thrown around loosely, but there are actually three distinct configurations, each with different results:

1. DPF-only delete — Replaces the Diesel Particulate Filter (DPF) and associated Diesel Oxidation Catalyst (DOC) with a straight delete pipe. Requires a supporting tune to disable regen cycles and clear DPF-related DTCs.
2. DPF + SCR/DEF delete — Adds removal of the Selective Catalytic Reduction (SCR) system and Diesel Exhaust Fluid (DEF) dosing hardware. Common on 2013+ trucks where both systems are present.
3. Full delete — Removes DPF, SCR, EGR (Exhaust Gas Recirculation), throttle valve, and all associated sensors. This is the most comprehensive configuration and delivers the largest HP and reliability gains when paired with a full performance tune.

Here's the thing — removing hardware alone doesn't make power. A 4-inch delete pipe dropping in place of the DPF assembly reduces exhaust backpressure, but the ECM still has its factory fueling and boost limits in place. The tune is the multiplier. It rewrites fueling maps, raises torque limits, optimizes injection timing, and eliminates the fuel-wasting post-injection events that drive DPF regen cycles.

The EGR system (Exhaust Gas Recirculation) routes hot exhaust gases back into the intake manifold to reduce combustion temperatures and NOx output. That's great for emissions, but it displaces fresh oxygen in the intake charge, increases intake soot contamination, and introduces pumping losses. Delete the EGR and the engine breathes cleaner air with more oxygen available for combustion — which translates directly to more efficient fuel burn and better response to tune adjustments.

Bottom line: if you're researching HP gains, understand that you're really asking "how much can a good tuner free up on this engine?" The delete hardware just removes the bottlenecks. The tune does the work.

The 6.7L Cummins ISB has been in production for Ram HD trucks since 2007.5, and the factory power ratings have climbed significantly across generations. According to Cummins ISB 6.7 specification data ^[2], the engine platform has supported ratings from 325 HP all the way to 400 HP in high-output configurations — and those are crankshaft HP figures per SAE J1349 rating methodology, not wheel horsepower.

Due to drivetrain losses through the transmission, transfer case, driveshaft, and differentials, a stock 6.7 Cummins will typically show 275–325 RWHP on a chassis dyno, depending on model year and equipment. Keep that in mind when you see "RWHP" figures online.

These numbers represent stock, unmodified trucks on a calibrated chassis dyno with standard correction factors applied. Altitude, tire size, and dyno type (inertia vs. load-bearing) will shift these figures by ±15–20 HP. The table is your anchor — every gain percentage you read online needs to be measured against one of these baselines, not a vague "stock" claim.

The DPF-only delete is the entry-level configuration. You're swapping out the DPF and DOC assembly for a straight 4-inch delete pipe, eliminating the physical restriction in the exhaust path, and loading a tune that disables regen cycles and clears DPF-related DTCs.

Here's what that physically does for power:

• Reduced exhaust backpressure — The DPF assembly creates meaningful restriction, particularly under load. Removing it lowers drive pressure on the turbo's exhaust side, improving turbine efficiency and spoolup.
• No regen fuel dosing — Factory calibrations inject additional fuel post-combustion to raise exhaust gas temperatures (EGTs) and burn accumulated soot in the DPF. Eliminating this frees up fuel that was being wasted on thermal management.
• Optimized fueling maps — The tune raises torque limits, sharpens injection timing, and leverages the lower backpressure to push more air and fuel through the engine efficiently.

On a 2007.5–2012 truck rated 350 HP at the crank, a well-executed DPF delete with a mild tune typically pushes output to approximately 390–420 crank HP — or roughly 315–350 RWHP on the dyno. That's real, usable power you'll feel immediately in throttle response and mid-range pull.

On a 2013–2018 truck starting at 370–385 HP, the same configuration can reach 420–450 crank HP, which translates to about 340–375 RWHP. The Diesel Dudes Technical Team has processed hundreds of these builds across all Cummins generations, and the 30–50 RWHP range consistently holds for DPF-only configurations on stock-hardware trucks ^[6].

One important clarification: some online sources quote these numbers as total HP, not gains. A truck making 350 RWHP after the tune isn't a 350 HP gain — it's a 350 HP truck. Make sure you're reading before-and-after numbers, not just post-tune peak figures.

This is where the numbers get interesting. A full delete removes every major emissions restriction simultaneously — and the tune can take full advantage of that clean slate.

The EGR system is the biggest player here. By routing hot, inert exhaust gas back into the intake manifold, the EGR system displaces fresh oxygen, raises intake air temps, and deposits soot throughout the intake tract and EGR cooler. Delete it, and your combustion chamber sees denser, cooler, cleaner air. The tune can then push more fuel into that improved charge without exceeding safe EGT targets.

According to The Diesel Dudes' own data from full delete builds ^[9], a properly tuned 6.7 Cummins with full emissions hardware removed typically gains 75–150 crank HP over stock on an unmodified engine. Here's how that plays out across generations:

• 2010–2012 Ram 2500 (350 HP stock) — Full delete + performance tune: 430–490 crank HP. Approximately 355–400 RWHP.
• 2015 Ram 2500 (370 HP stock) — Full delete + tune: 450–500+ crank HP. Approximately 370–420 RWHP.
• 2019–2024 HO (400 HP stock) — Full delete + tune: 480–530+ crank HP. Approximately 390–440 RWHP.

For builds that go further — larger turbocharger, upgraded CP3 fuel pump replacing the factory CP4, performance injectors, better intercooling — the 150–250 HP over-stock range is achievable. But these are built setups, not what you get from bolt-on delete hardware and a tune alone. Frame your expectations accordingly.

The Diesel Dudes' full delete bundles are spec-matched by model year and include everything needed: EGR delete kit, DPF delete pipe, and a tuner calibrated specifically for the hardware being removed ^[6]. From $1,784 for a 2010–2012 bundle up to $6,734+ for a 2022–2024 truck, the kit pricing reflects the complexity of each generation's emissions architecture.

Disclosure: The Diesel Dudes sells some of the products mentioned in this article. Our recommendations are based on hands-on testing and customer feedback.

Here's exactly why the numbers are all over the place, and how to read them critically:

1. Crank HP vs. RWHP — This is the biggest source of confusion. A 100 crank HP gain translates to roughly 75–85 RWHP after drivetrain losses. Some sources quote crank; others quote wheel. If they don't specify, assume the lower number is RWHP and the higher is crank — and mentally translate accordingly.
2. Starting baseline — A 2008 truck at 350 HP stock showing 480 HP after a full delete is a 130 HP gain. A 2022 HO truck at 400 HP showing the same 480 HP is only an 80 HP gain. The absolute number post-tune is irrelevant without the baseline.
3. Tune aggressiveness — A mild tow tune optimized for reliability and transmission longevity delivers far less peak HP than a "race" or "max effort" tune. Both are legitimately "deleted and tuned" trucks.
4. Dyno methodology — Inertia dynos and load-bearing dynos produce different numbers on the same truck. Altitude correction factors, ambient temperature, and tire size all move the needle by ±15–25 HP on a single vehicle.
5. Supporting mods — HP numbers from a truck with a larger turbo, upgraded injectors, and a free-flowing intake are often quoted without disclosing those mods. A stock-hardware delete will not replicate those results.
6. Fuel quality and altitude — ULSD fuel quality varies by region. High-altitude dyno pulls consistently show lower output than sea-level numbers.

The Diesel Dudes cuts through this noise with generation-specific guidance. A 2013–2018 truck running our full delete bundle with an EFI Live Autocal V3 tune on a stock engine will realistically land in the 450–500 crank HP range. That's the honest number — and it's still a major improvement over a 385 HP stock truck grinding through regen cycles every 300 miles.

Let's talk about what actually affects your day-to-day ownership experience — because for most 6.7 Cummins owners, the HP gains are secondary to fixing the truck's chronic annoyances.

Fuel Economy: Real-world reports from deleted 6.7 Cummins trucks consistently show 2–4 MPG improvements on mixed driving cycles ^[9]. The gains come from multiple directions simultaneously: no fuel-wasting regen post-injections, improved combustion efficiency from better intake air quality (no EGR soot), and reduced exhaust pumping work. At $4.50/gallon diesel and 15,000 miles/year, a 3 MPG improvement on a truck averaging 15 MPG saves roughly $450–600 annually.

EGT Reduction: Exhaust gas temperatures (EGTs) under sustained load — towing, grades, high-speed highway — typically drop 100–200°F after a full delete and tune. This happens because the tune optimizes injection timing for efficiency rather than emissions management, and because the EGR system is no longer introducing hot exhaust into the combustion process. Lower EGTs mean more thermal headroom for the turbocharger and pistons under demanding conditions.

Regen Elimination: Active DPF regeneration cycles on stock trucks can trigger every 200–500 miles depending on duty cycle, soot load, and driving conditions. Each regen injects fuel to raise EGTs to 1,000–1,200°F to burn soot — and that fuel ends up partially in your crankcase oil, diluting it. Deleting the DPF ends regen cycles entirely. Oil stays cleaner longer, and you're not watching your fuel economy crater every few hundred miles on the highway.

Throttle Response: Factory calibrations include significant tip-in delays and torque limiters designed to protect emissions hardware and meet emissions test cycles. A delete tune removes those limiters, resulting in noticeably more linear and immediate throttle response. Trucks that felt sluggish off the line or hesitant under load respond completely differently after tuning.

Legal Notice: Removing or tampering with emissions equipment may violate the federal Clean Air Act and state emissions regulations. Penalties can include fines up to $5,000 for individuals. Check your local and state laws before modifying emissions equipment on any vehicle driven on public roads.

The EPA's position on emissions tampering is grounded in federal statute. Under the Clean Air Act, 42 U.S.C. § 7522(a)(3), it is a prohibited act to remove or render inoperative any emission control device on a motor vehicle used on public roads — and to manufacture or sell parts designed to bypass such devices.

The EPA has actively pursued enforcement against both installers and parts sellers. In January 2024, the EPA and DOJ reached a major settlement with Cummins, Inc. over emissions defeat devices on 630,000 model year 2013–2019 Ram 2500 and 3500 diesel vehicles ^[2]. That settlement confirmed that defeat device enforcement extends to OEM-level software and is not limited to aftermarket modifications.

EPA enforcement actions against aftermarket parts sellers have resulted in multi-million dollar consent decrees, as documented in the publicly filed consent decree ^[3], which establishes the legal precedent for civil penalties against defeat-device sellers and installers.

On the regulatory front, the EPA issued new 2026 guidance removing the requirement for DEF sensors specifically, allowing NOx sensors as a substitute — but this guidance does not legalize DPF or EGR removal for on-road vehicles ^[4]. It's a narrow technical update, not a green light for full deletes on street trucks.

Warranty implications: Ram/Mopar warranty documentation specifies that damage resulting from modification or tampering with emissions control systems may not be covered under the powertrain warranty. For trucks still under factory warranty, this is a direct financial risk beyond the regulatory exposure.

The Diesel Dudes sells delete products for off-road, competition, and closed-course use only. If your truck operates on public roads in a jurisdiction with emissions inspections or opacity testing, research your state's specific requirements before proceeding.

A tuned and deleted 6.7 Cummins making 150+ HP over stock is a legitimately powerful truck. It's also a truck with higher cylinder pressures, higher drive pressures on the turbo, and significantly more torque running through a transmission that was calibrated for a 650–1,000 lb-ft engine. Here's what to watch:

68RFE Transmission: The 68RFE automatic is the standard transmission in most Ram 2500 and 3500 trucks from 2007.5 onward. It's a solid unit at stock power levels but is widely documented as a weak point when torque climbs past 900–1,000 lb-ft at the input shaft. Clutch packs, the valve body, and line pressure management are the common failure modes under elevated torque. If you're running an aggressive performance tune on a 68RFE-equipped truck, either get a transmission tune that manages shift pressure and line pressure appropriately, or budget for built transmission internals on high-mileage trucks you're pushing hard.

EGT Management: Exhaust gas temperatures are the health indicator for your turbocharger and pistons under load. Factory calibrations are designed to keep EGTs in a safe window — typically below 1,250°F sustained. A delete tune that's too aggressive on fueling can push EGTs beyond safe limits, especially under extended towing loads or at altitude. Monitor EGTs with a quality pyrometer during the first several tow cycles after tuning. The Edge EAS EGT Probe Kit available through The Diesel Dudes gives you real-time EGT data at the turbine outlet.

Aisin AS69RC and G56: If your truck has the Aisin automatic (HO configuration) or G56 6-speed manual, you have meaningfully more transmission headroom. These units handle elevated torque significantly better than the 68RFE, but they're not bulletproof at extreme power levels either.

Fuel System: The 2011–2018 trucks use a CP4.2 high-pressure fuel pump (HPFP), which has a known failure mode under aggressive fueling demands and is sensitive to fuel quality. Trucks running aggressive power levels should run quality ULSD and consider CP3 conversion kits at high mileage. The 2007.5–2010 platform uses the more robust CP3, which handles elevated fueling demand better.

The Diesel Dudes Technical Team recommends matching tune aggressiveness to your actual use case. A conservative tow tune on a daily driver that hauls 5th-wheel trailers will deliver 50–80 HP over stock, protect your transmission, and run for 200,000+ miles without drama.

One of the most common mistakes buyers make is assuming all 6.7 Cummins delete kits are interchangeable. They're not. Each generation runs different EGR cooler configurations, different exhaust routing, and different aftertreatment architectures. The tune files are also year-specific — a 2018 tune loaded on a 2013 ECM will not calibrate correctly.

Each bundle includes the EGR delete kit, DPF delete pipe, and a matched tuner — everything you need to complete the conversion without sourcing components piecemeal. The 2013–2018 bundle starts at $1,832 and the 2019–2021 bundle starts at $2,394, reflecting the more complex fifth-gen emissions architecture ^[9]. The 2022–2024 platform requires significantly more engineering work and starts at $6,734, consistent with the complexity of the latest-generation SCR and EGR systems.

Cab & Chassis configurations require a different pipe setup — if you're running a 4500 or 5500 series truck, make sure you select the C&C-specific bundle rather than the standard pickup configuration.