Who Makes the Best L5P Delete Kit? 2026 Buyer's Guide

TL;DR

• The best L5P delete kit is a complete one: EGR, DPF/CAT and DEF/SCR handled together, with a matched delete tune. Our L5P Full Delete Bundle is built that way.
• Stock, the L5P makes 445 hp and 910 lb-ft (2017–2023). The 2024 refresh raised that to 470 hp and 975 lb-ft.
• Our L5P delete tune offers five power levels, Stock up to +200 hp, switchable from the steering wheel.
• The L5P's E41 ECM is locked from the factory. Our bundle includes the unlock/ECM upgrade kit, so no separate unlocked ECM is needed.
• Hardware without a tune means codes, "See Dealer" messages and limp mode. Tune and hardware have to go in together.

The L5P is the strongest Duramax GM has built. It's also the one most weighed down by emissions hardware: frequent DPF regens, DEF faults on cold mornings, EGR soot in the intake and the occasional derate at the worst possible moment.

A proper delete fixes all of it at once. The catch is that "proper" matters more on the L5P than on any older Duramax. Its ECM is locked, its emissions parts talk over a CAN network, and a half-done job leaves you fighting the truck's computer. Here's what separates a kit that works from one that doesn't.

What Is an L5P Delete Kit and What Does It Include?

An L5P delete kit removes the factory EGR, DPF/CAT and DEF/SCR systems and reprograms the ECM so the truck runs without them. A complete kit is hardware plus tuning; either one alone leaves you with codes.

The L5P carries three emissions systems:

• EGR (Exhaust Gas Recirculation) routes hot exhaust back into the intake, raising intake temps and coating the manifold and valves in soot.
• DPF (Diesel Particulate Filter) traps soot and forces active regens that burn extra fuel and spike exhaust gas temperatures (EGT).
• DEF/SCR (Diesel Exhaust Fluid / Selective Catalytic Reduction) injects urea to cut NOx. When a sensor or heater fails, the truck derates.

A complete L5P kit covers each one:

• EGR delete — block-off plates and hardware to seal the EGR circuit. See our L5P EGR Delete Kit.
• DPF/CAT delete — a stainless DPF & CAT delete pipe or a 5" downpipe-back exhaust.
• DEF/SCR delete — handled by the tune, plus CAN bus plugs that replace the NOx and DEF module connectors.
• Delete tune — custom ECM calibration that shuts off regens and clears emissions codes.

What Are the Real-World Gains from an L5P Delete?

With a full delete and our tune, you pick from five power levels: Stock, +50 hp, +80 hp, +130 hp and +200 hp. The top level can swing about 20 hp either way depending on whether you run a cold air intake and full exhaust.

GM calibrated the L5P for emissions compliance first. Stock output is 445 hp and 910 lb-ft on 2017–2023 trucks, and 470 hp and 975 lb-ft on the 2024 refresh. Remove the EGR and DPF restrictions, recalibrate fueling and boost, and that headroom opens up.

• Fuel economy: customers typically report 2–5 MPG better, mostly from ending regen cycles that dump extra fuel into the exhaust.
• Exhaust temps: no more regen-driven EGT spikes, which is easier on the turbo when you tow.
• Reliability: no DEF heaters, NOx sensors or EGR coolers left to fail, and no "Exhaust system service required" limp mode.
• Drivability: sharper throttle and faster spool without hot EGR gas in the charge air.

Need help choosing a power level for how you use your truck? Contact our tuning team.

How Do the L5P Delete Kit Options Compare?

Only a full bundle deletes all three systems with a tune written for that exact hardware. Tune-only and hardware-only setups can work, but only if you source the missing half correctly.

Prices as listed on tunerdepot.com at time of writing. Hardware without a tune leaves the ECM expecting parts that are gone, which means codes and derates.

What Makes Our L5P Full Delete Bundle Stand Out?

The GM/Chevy Duramax 6.6 L5P Full Delete Bundle (2017–2023) ships as one matched system, so the tune is written for the exact parts in the box.

What's included:

1. Tuning unlock tool, including the E41 ECM Upgrade Kit by HP Tuners (no separate unlocked ECM to buy)
2. MPVI4 delete tuner and custom tune files with Shift on the Fly
3. CAN bus plugs for the NOx and DEF module connectors
4. Stainless DPF/CAT delete pipe or 5" full exhaust, with or without muffler
5. Full EGR delete kit with hardware and gaskets

Optional add-ons: a 3.5" stainless downpipe that also removes the DOC and flows about 20% better than stock, and a 1-year extended warranty on the bundle.

After checkout you'll get a vehicle information form (VIN, year, model). We build your custom tunes from it, and a step-by-step video shows the tune install.

Which L5P Trucks Are Compatible?

Our L5P bundle fits 2017–2023 Chevy Silverado and GMC Sierra 2500HD/3500HD pickups with the 6.6L L5P. 2024+ bundles are listed but not yet available.

Not sure which you have? Use our Build a Kit or call 866-401-6313 before ordering.

What Tuning Options Are Available for the L5P?

Every L5P tune starts with unlocking the E41 ECM, which GM locks from the factory. Skip it and no tune file will load.

From there you have two routes:

• Full bundle with MPVI4 tuner — the L5P Full Delete Bundle includes the unlock/ECM upgrade kit, the MPVI4 and custom tunes. Best for most owners doing the whole job at once.
• Software only — the Duramax L5P 2017–2023 Delete Software is the tune files with Shift on the Fly, plus the 8 required tuning credits as an option. Good if you already have hardware, a tuning device or credits.

Both give you the same five power levels (Stock to +200 hp), stop regens and clear emissions codes. Either way you'll need a Windows PC to load the tune; Mac and Linux won't work. Clear all existing codes before flashing, or some can become permanent.

Browse all delete tuners.

How Hard Is It to Install?

Most owners do it themselves in a garage or driveway with basic hand tools; no cutting or welding. Plan on a full day for a first-timer, longer if you add the 5" exhaust and downpipe.

The EGR is the longest part because of the coolant lines, so have fresh coolant on hand. Detailed instructions and videos are emailed after purchase, and our tech support team can walk you through any step. A diesel shop that has done L5P deletes can usually finish in one working day.

What Upgrades Pair Well with an L5P Delete?

A cold air intake and EGT monitoring are the two best add-ons once the emissions hardware is gone.

• Cold air intake: the S&B Cold Air Intake for the L5P flows 47.7% more air than the factory box and keeps the MAF in its stock spot, so no extra tuning is needed. It also helps you get the most from the +200 hp level.
• EGT monitoring: the Edge EAS EGT Probe Kit reads through an Edge CTS3 monitor so you can watch exhaust temps when towing hard.
• Muffler: a straight pipe is louder. Our 5" Optimal Flow Muffler takes the drone out of the cab.

Gear Up: Your L5P Shopping List

Related Reading

• Get the Most Out of Your 2011-2016 Duramax LML with the Full Delete Kit
• 6.6L Duramax L5P Delete Guide: Complete Guide for 2017-2025 L5P Models

Can You Get an L5P Delete Kit with an EZ Lynk Tuner?

Yes. You can build an L5P delete kit with an EZ Lynk tuner using the Build a Kit tool on Tuner Depot. It shows every tuning option available for your truck, so you can pick EZ Lynk instead of taking whatever tuner comes in a fixed bundle.

The builder walks you through each step and only shows parts that fit your truck:

1. Select your truck — year, make, engine (L5P) and body style.
2. Pick your tuner — choose EZ Lynk from the available tuning options. Each package lists the tune files, cables and switches it includes.
3. Pick your EGR delete kit.
4. Pick your delete pipe or exhaust — straight delete pipe or a full downpipe-back system.
5. Add a muffler and exhaust tips — only sizes that match your pipe diameter are shown.
6. Add a cold air intake and accessories — CAN bus plugs, harness plugs and other compatible parts appear for your truck.
7. Complete your build — review everything in one summary, then add it all to the cart together.

Save 5% with Build a Kit: when your build includes a tuner, an EGR kit and an exhaust, Tuner Depot takes an extra 5% off select products. All three are required for the discount.

Start your EZ Lynk L5P build →

The Bottom Line

Frequently Asked Questions

Do I need a tuner with an L5P delete kit?

Yes. The ECM monitors all three emissions systems and will set codes and derate the truck if hardware is removed without a delete tune.

Does the L5P need an unlock before tuning?

Yes. The E41 ECM is locked from the factory. Our full bundle includes the HP Tuners E41 ECM Upgrade Kit, so you don't need to buy a separate unlocked ECM.

DPF/CAT pipe or 5" full exhaust?

The delete pipe sounds close to stock, especially with a muffler. The 5" downpipe-back exhaust flows more and is louder, and it's the better match for the +200 hp level and heavy towing.

Are CAN bus plugs really required?

Yes. They replace the NOx and DEF module connectors and close the signal back to the ECM. They're included in the full bundle, or sold separately as the L5P CAN Bus Plug Kit.

Will a delete void my GM warranty?

Expect it to. Dealers routinely deny powertrain claims on trucks with emissions hardware removed or ECM changes. Many owners wait until the factory warranty runs out.

Can I go back to stock later?

The pipes bolt to factory mounts, so keep your original parts. Several customers have needed them later for troubleshooting or resale.

Shop the Parts

• Full Delete Kits
• Delete Tuners
• Delete Pipes
• EGR Delete Kits
• Harness Plugs