How Much Horsepower Can You Gain with L5P Delete Kit?

The 6.6L Duramax L5P engine is known for its impressive factory performance and reliability. However, for truck owners who want to push their power to the next level—whether for towing, competition, or recreational performance—installing a delete kit remains one of the most impactful upgrades available. But exactly how much horsepower can you gain with an L5P delete kit, and what does the process involve?

In this in-depth article, we will explore the real-world horsepower improvements, the key components involved, the reasons for the gains, and what you need to successfully complete an L5P delete.

Understanding the L5P Platform and Emissions Control Limitations

The L5P engine, introduced in 2017, was a major leap forward for GM's Duramax diesel lineup. With a factory-rated 445 horsepower and 910 lb-ft of torque, it offered substantial power for heavy-duty tasks. However, these numbers are achieved while the engine is burdened with modern emissions control systems, such as the Diesel Particulate Filter (DPF), Exhaust Gas Recirculation (EGR) system, Diesel Exhaust Fluid (DEF) injection, and the Diesel Oxidation Catalyst (DOC).

These systems, while environmentally mandated, create restrictions in the engine’s breathing, reduce thermal efficiency, and introduce failure-prone components that increase maintenance costs. That’s where an L5P delete kit enters the picture.

How Much Horsepower Can You Actually Gain?

The most frequently asked question about deleting an L5P is simple: How much more horsepower can I get?

The answer depends on several factors, including the quality of your delete kit, the tuning software you use, the exhaust modifications you install, and your specific vehicle configuration. However, in general:

• A fully deleted and tuned L5P can gain between 100 to 150 additional horsepower over stock.

• Torque increases are also substantial, with gains of up to 200–250 lb-ft reported.

These numbers are achieved through improved airflow, optimized fueling, higher turbo efficiency, and the absence of performance-sapping emissions cycles. In many cases, truck owners also report faster throttle response, quicker turbo spool, and reduced heat buildup under load.

Why Deleting the L5P Increases Horsepower

The horsepower gains from an L5P delete kit are not just about turning off warning lights or avoiding regen cycles. They stem from fundamental mechanical and thermal improvements:

• Reduced Backpressure: The DPF and DOC restrict exhaust flow, which increases turbo lag and limits boost pressure. Removing these components dramatically improves exhaust velocity.

• Cooler Combustion Temperatures: The EGR system recirculates hot exhaust gases back into the intake. Deleting it reduces intake temperatures, improving combustion efficiency.

• More Aggressive Fuel Mapping: Custom tuning software that accompanies delete kits allows for significantly more aggressive fueling strategies, timing adjustments, and boost control.

• Consistent Performance: Without emissions system interruptions like regen cycles, power delivery becomes more predictable and consistent under all conditions.

Combined, these changes allow the engine to operate closer to its true mechanical potential, unhindered by artificial restrictions.

What's Needed to Delete L5P?

To fully unlock the power of your L5P Duramax through a delete kit, you will need several key components and supporting tools. A proper delete is not a single part—it is a system of upgrades that work together to eliminate restrictions, improve airflow, and enhance tuning flexibility. Here's what you'll need:

1. DPF Delete Pipe or Turbo-Back Exhaust

This replaces the factory Diesel Particulate Filter and offers a straight-through exhaust flow. Commonly available in 4” or 5” diameters, these exhaust systems significantly reduce restriction, improve turbo spool, and enhance exhaust tone.

2. EGR Delete Kit

This includes block-off plates, coolant reroute lines, and the necessary hardware to fully remove the EGR valve and cooler assembly. Eliminating the EGR system prevents soot buildup and intake contamination, leading to a cleaner and more efficient combustion cycle.

✅ Recommended Product: For a complete and proven solution, consider the DynoVox EGR & DPF Delete Kit for 2017–2023 Sierra/Silverado L5P 6.6L Duramax. This all-in-one kit includes everything needed for a comprehensive delete, ensuring compatibility, performance gains, and a straightforward installation process.

3. Tuning Software

A tuner or tuning device is required to reprogram the ECM (Engine Control Module) so it no longer expects inputs from the now-removed emissions systems. It is also what delivers the horsepower and torque gains by modifying fuel delivery, boost pressure, and timing curves. Popular L5P tuning platforms include custom handheld tuners or bench/remote ECM programming options—many of which work seamlessly with delete kits like DynoVox’s.

4. DEF Delete (If Applicable)

You may also choose to remove the DEF tank and dosing system. This step requires additional tuning but eliminates the need for DEF refills and resolves issues related to faulty DEF sensors or freezing fluid in colder climates.

5. Installation Tools and Expertise

While experienced diesel enthusiasts may choose to handle the installation themselves, many truck owners prefer to work with a professional diesel performance shop. Proper installation ensures optimal results and avoids common mistakes during ECM tuning or exhaust system fitment.

🛠️ The DynoVox L5P delete kit is designed with ease-of-installation in mind, offering high-quality components that are precision-engineered for a perfect fit on 2017–2023 GM 6.6L Duramax trucks.

Important Note: Delete kits are strictly intended for off-road or competition use only. They may not be legal for on-road use in certain jurisdictions. Always review local and federal regulations before modifying any emissions-related components on your vehicle.

5 Game-Changing Performance Benefits of an L5P Delete Kit

While horsepower gains are often the headline, the real-world benefits of deleting your L5P Duramax go much further. Here are five key reasons performance enthusiasts and heavy-duty drivers choose to upgrade:

1. Improved Throttle Response

Stock emissions components—especially the DPF and EGR—cause hesitation in acceleration. Deleting these systems allows for instant throttle feedback, especially under load. This means quicker highway merges, better off-road control, and faster turbo spool.

2. Lower Exhaust Gas Temperatures (EGTs)

EGTs play a critical role in engine health, especially when towing. With emissions systems in place, EGTs can soar beyond safe limits. Post-delete, users often report reductions of 100–200°F in sustained towing conditions, which helps preserve turbo longevity and piston integrity.

3. Better Fuel Economy

With reduced backpressure and optimized air/fuel ratios through custom tuning, L5P trucks often see a fuel economy improvement of 10–20%. That's up to 3 extra MPG, especially when combined with a high-flow exhaust system.

4. Increased Towing Performance

Whether you're hauling a camper, boat, or trailer, delete kits make towing effortless. Increased torque and faster power delivery mean fewer downshifts, less strain on the engine, and smoother climbs, even at altitude or over long grades.

5. Reduced Maintenance Costs

Emissions systems are notorious for expensive repairs. A failed DPF, EGR cooler, or DEF sensor can cost thousands. By deleting these systems, owners eliminate regen cycles, prevent soot buildup, and avoid costly component replacements altogether.

Together, these benefits transform your L5P from a capable work truck into a high-performance, long-haul powerhouse that’s cheaper to operate and more fun to drive.

Conclusion: Should You Delete Your L5P for More Power?

If your goal is to maximize the horsepower, torque, and long-term reliability of your Duramax L5P engine, a complete delete kit is an extremely effective solution. With gains of over 100 horsepower, improved fuel economy, and fewer maintenance concerns, it offers substantial value to truck owners who demand more from their vehicles.

However, the decision should be made carefully, with full understanding of the legal and warranty implications. For off-road builds, competitive towing, or dedicated work trucks, an L5P delete kit can transform your vehicle into a more powerful and reliable machine.

Frequently Asked Questions About L5P Delete Kits

Q: Will deleting my L5P void the warranty?
Yes. Any modification to emissions systems will void the powertrain warranty. However, many owners believe the long-term benefits outweigh the warranty concerns.

Q: Is custom tuning required for an L5P delete?
Absolutely. The ECM must be reprogrammed to prevent limp mode and maximize performance. Simply removing components without tuning will trigger error codes and reduce drivability.

Q: Can I daily drive a deleted L5P?
While legally it must be used for off-road purposes, a deleted L5P is often smoother and more responsive in daily driving than stock—especially for those who tow frequently or live in extreme climates.

Q: How long does installation take?
Depending on experience, installation typically takes 4 to 8 hours. Tuning may require ECM removal and reinstallation, which can add time.