Q: Is a tuner required for this kit?

While the 2001-2007 trucks do not have complex DPF sensors, a performance tuner is highly recommended for LLY and LBZ models to optimize fuel mapping and prevent potential "Check Engine" lights related to EGR or CAT flow changes.

Q: How does T-409 Stainless compare to Aluminized steel?

T-409 stainless steel contains chromium, providing much better resistance to rust and corrosion in high-heat diesel applications. It will develop a surface patina (magnetic) but will not rot through like cheaper aluminized pipes.

Q: What is included for installation?

The package includes the necessary delete pipe sections, high-quality clamps, and hangers. Most users find the installation takes approximately 1 hour with basic hand tools.

2001-2007 6.6L GM Duramax LLY LBZ LB7 4" & 5"Downpipe-back Delete Pipe DieselPerf

2001-2007 6.6L GM Duramax LLY LBZ LB7 4" & 5"Downpipe-back Exhaust DieselPerf

2019-2025 6.7L Dodge Ram Cummins 5'' Downpipe-Back DPF Delete Pipe DieselPerf

2001-2007 6.6L GM Duramax LB7 LLY LBZ 4" & 5" Downpipe-Back Exhaust

$569.00

PATRIOT DAY SALE: 13% OFF

In stock

Ships from USA in 1-2 Business Days

Size

4" Downpipe-Back(2001-2007) 4" Downpipe-Back w/Muffler(2001-2007) 5" Downpipe-Back(2001-2007) 5" Downpipe-Back w/Muffler(2001-2007)

Shipping Policy at Dieselperf, Learn More

Product Specifications

SKU DIPSJ-007
Vehicle Fitment 2001-2007 LBZ LLY LB7 6.6 Duramax

Install difficulty: Moderate; recommended for those with mechanical experience.

Custom tuning is required after installation to clear codes and optimize performance.

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Upgrade the exhaust system on your 2001–2007 Chevrolet Silverado or GMC Sierra 2500HD/3500 equipped with a 6.6L Duramax LB7, LLY, or LBZ engine. This T409 stainless steel downpipe-back exhaust system replaces the exhaust section downstream of the factory downpipe and is available in 4-inch or 5-inch configurations, with or without a muffler. It is designed for pickup models only and does not fit Cab & Chassis trucks. Some shorter wheelbase configurations may require pipe trimming during installation.

2001-2007 Duramax downpipe-back exhaust for Chevy and GMC Silverado Sierra pickups

Key Features

Downpipe-Back Exhaust Configuration:
Replaces the exhaust system downstream of the factory downpipe while retaining the original turbo downpipe.

4-Inch and 5-Inch Pipe Options:
Choose a 4-inch system for a balanced exhaust upgrade or a 5-inch system for a larger exhaust path and deeper diesel tone.

Muffler and Non-Muffler Versions:
Muffler-equipped options provide a more controlled exhaust note, while non-muffler configurations deliver a louder and more aggressive sound.

T409 Stainless Steel Construction:
Built from durable T409 stainless steel for resistance to heat, corrosion, and demanding road conditions.

Mandrel-Bent Tubing:
Smooth mandrel bends help maintain a consistent pipe diameter and support unrestricted exhaust flow.

Heavy-Duty Construction:
The approximately 2 mm pipe wall is designed to provide strength and durability for diesel truck applications.

Deeper Duramax Exhaust Tone:
Enhances the natural sound and more aggressive exhaust note of the 6.6L Duramax engine, with the final volume depending on pipe size and muffler selection.

Available Options

Option	Pipe Size	Muffler
4" Downpipe-Back	4 inch	No
4" Downpipe-Back w/Muffler	4 inch	Yes
5" Downpipe-Back	5 inch	No
5" Downpipe-Back w/Muffler	5 inch	Yes

Which Option Should You Choose?

The 4-inch non-muffler system provides a more aggressive exhaust note without moving to the largest pipe diameter.

The 4-inch muffler system is a practical option for daily-driven or towing trucks where a more controlled sound is preferred.

The 5-inch non-muffler system offers the deepest and most aggressive exhaust tone of the four configurations.

The 5-inch muffler system combines the larger 5-inch appearance and tone with a muffler to help reduce overall exhaust volume.

Actual sound will vary based on engine condition, cab and bed configuration, existing modifications, and selected exhaust option.

Technical Specifications

Specification	Detail
Product Type	Downpipe-back exhaust system
Engine	6.6L Duramax V8
Engine Codes	LB7, LLY and LBZ
Model Years	2001–2007 LB7/LLY/LBZ applications
Vehicle Models	Chevrolet Silverado and GMC Sierra 2500HD/3500
Pipe Diameter	4 inch or 5 inch
Material	T409 stainless steel
Wall Thickness	Approximately 2 mm
Construction	Mandrel-bent tubing
Muffler	Available with or without muffler
Cab & Chassis Fitment	Not compatible

Vehicle Fitment

Chevrolet Silverado

2001–2004 Silverado 2500HD/3500 with 6.6L Duramax LB7
2004.5–2005 Silverado 2500HD/3500 with 6.6L Duramax LLY
2006–2007 Silverado 2500HD/3500 with 6.6L Duramax LBZ

GMC Sierra

2001–2004 Sierra 2500HD/3500 with 6.6L Duramax LB7
2004.5–2005 Sierra 2500HD/3500 with 6.6L Duramax LLY
2006–2007 Sierra 2500HD/3500 with 6.6L Duramax LBZ

Important Fitment Notes

Does not fit Cab & Chassis models.

What’s Included

Downpipe-back exhaust pipe sections
Exhaust clamps
Exhaust hangers
Muffler on options specifically labeled “w/Muffler”

The number and shape of individual pipe sections may vary by selected diameter and muffler configuration.

Installation Notes

This system is designed to connect downstream of the factory turbo downpipe. Some shorter wheelbase configurations may require cutting or trimming an intermediate pipe section to achieve the correct overall length.

Installation time varies depending on vehicle condition, corrosion, wheelbase, exhaust configuration, and installer experience. Professional installation is recommended when exhaust alignment or pipe modification is required.

Check all clamps, connections, hangers, and clearances after installation. Recheck and retighten the exhaust clamps after the first complete heat cycle.

Frequently Asked Questions

Is this a DPF delete pipe?
No. The listed LB7, LLY, and LBZ trucks were produced before the 2007.5 LMM DPF-equipped platform. This product is a downpipe-back exhaust system for compatible 2001–2007 Duramax applications.

What does downpipe-back exhaust mean?
A downpipe-back exhaust replaces the exhaust components after the factory turbo downpipe. It does not replace the downpipe itself.

Does this system replace the factory turbo downpipe?
No. A downpipe-back system begins downstream of the factory downpipe. It should not be confused with a turbo-back exhaust system.

What is the difference between the 4-inch and 5-inch systems?
The main difference is pipe diameter. The 5-inch system has a larger exhaust path and generally produces a deeper tone. The 4-inch system offers a more moderate pipe size and exhaust sound.

Which options include a muffler?
The 4" Downpipe-Back w/Muffler and 5" Downpipe-Back w/Muffler options include a muffler. Options without “w/Muffler” use a non-muffler configuration.

Will the non-muffler version be louder?
Yes. A non-muffler exhaust configuration generally produces a louder and more aggressive exhaust note than the corresponding muffler-equipped version.

Will cutting be required?
Some shorter wheelbase, cab, or bed configurations may require trimming an intermediate pipe. Measure and test-fit all components before cutting.

Does it fit Cab & Chassis trucks?
No. This system is not designed for Cab & Chassis applications.

Is a tuner required?
A tuner is not automatically required for a conventional downpipe-back exhaust installation. Requirements may vary depending on the truck’s existing exhaust configuration, calibration, and other modifications.

Is a downpipe-back exhaust illegal?
Legality depends on local and state emissions and noise laws. Check all applicable regulations before purchase and installation.

How much HP will a downpipe-back exhaust add?
Power gains vary by vehicle condition and setup. This product is primarily designed to improve exhaust flow and sound rather than guarantee a specific horsepower increase.

Is a downpipe-back exhaust bad for the engine?
When properly installed on a compatible truck, it is not inherently bad for the engine. Always confirm fitment and install all components correctly.

Compliance Notice

The purchaser and installer are responsible for confirming that the selected exhaust configuration complies with all applicable federal, state, and local laws.

General Performance & Technical Questions

Q1: What are the primary benefits of an EGR delete on a Duramax?

Engine Longevity: Stops abrasive soot and carbon from entering your intake manifold and scoring cylinder walls.
Lower EGTs: Reduces overall engine operating temperatures by eliminating the recirculation of hot exhaust gases.
Improved MPG: Many owners report up to a 20% increase in fuel economy when paired with a proper off-road tune.
Turbo Protection: Prevents "carbon choking" of the turbocharger vanes and intake valves, extending the life of your top-end components.

Q2: What tools are required for installation?

You will need a standard set of metric sockets, wrenches, and screwdrivers. Since the EGR cooler is integrated into the cooling system, you will also need coolant catch pans and fresh Dex-Cool to refill the system after the reroute.

Q3: Will an EGR delete damage my engine?

No. When installed correctly with supporting tunes, it actually improves reliability. It optimizes airflow, reduces thermal stress on the head gaskets, and prevents the common "clogged EGR" issues that lead to expensive repairs.

Q4: Will removing the EGR cause my truck to smoke?

With a high-quality "clean" tune (from platforms like EFI Live or EZ Lynk), your truck should not produce excessive black smoke. Without proper tuning, the air-fuel ratio will be unbalanced, leading to poor combustion and heavy smoke.

Q5: Is an EGR delete legal for street use in the U.S.?

No. These kits are sold strictly for OFF-ROAD / RACING USE ONLY. Under EPA federal law, removing emissions equipment from a vehicle operated on public highways is illegal and will cause the vehicle to fail emissions inspections (Smog Checks).

LLY (2004.5–2005) Specifics

Q6: Does the LLY kit include a high-flow intake pipe?

Yes. Most LLY kits feature a high-flow intake bridge designed to replace the restrictive factory piece, significantly increasing airflow for your 2005 Duramax.

Q7: Can I install the 2005 LLY kit myself?

Yes. The LLY is a very DIY-friendly platform. It is a direct bolt-on solution that typically takes 2–3 hours for an experienced enthusiast with basic hand tools.

LMM (2007.5–2010) Specifics

Q8: Which trucks are compatible with the LMM kit?

This kit is specifically for 2007.5–2010 Silverado and Sierra 2500/3500 HD models equipped with the 6.6L LMM engine.

Q9: How long is the installation for an LMM Duramax?

Due to the engine bay layout, the LMM is more labor-intensive than the LLY. Expect a 4–6 hour installation time.

LML (2011–2016) Specifics

Q10: What materials are used in the LML delete kit?

Our LML kits are manufactured from CNC-machined billet aluminum and high-grade stainless steel to ensure they handle the high boost pressures and heat cycles of the 6.7L platform.

Q11: Is this compatible with a 2015 Chevrolet Silverado?

Yes. It is fully compatible with 2011–2016 LML models, including the 2015 Silverado/Sierra 2500 and 3500 HD.

L5P (2017–2025) Specifics

Q12: What does the L5P EGR delete improve?

By removing the EGR valve and cooler on the 2017+ L5P, you allow the engine to pull in 100% fresh, oxygen-rich air. This results in more consistent torque and lower coolant temperatures—highly noticeable when towing heavy loads.

Q13: Is the L5P installation complicated?

While the L5P engine bay is compact, the kit is designed for a precise fit. Most DIYers can complete the installation within a few hours. Note: L5P tuning is specialized; ensure your ECM is unlocked and ready before starting the physical install.

Troubleshooting & Maintenance

Q14: Will this kit fix the issue of intake heater bolts falling into the engine?

No. This kit deletes the EGR system. The "heater grid bolt" issue is a separate hardware failure. If you are concerned about those bolts, we recommend a "Grid Heater Delete" in addition to this kit.

Q15: Will my truck pass emissions with this kit?

No. Removing the EGR system is a "fail" for visual and OBDII emissions scans in states that require testing.

Shipping & Delivery Policy

At DieselPerf, we specialize in high-performance diesel emission system accessories. Our mission is simple: to deliver the parts you need with maximum efficiency, security, and transparency. Below are the guidelines we follow to ensure your order reaches you safely.

1. Perfecting Your Delivery

To ensure a seamless experience and avoid unnecessary surcharges, please keep the following in mind:

Precision Matters: Always verify your shipping address at checkout. Accurate data prevents costly rerouting fees.
Address Classification: Carriers determine rates based on zoning. If your business is located in a residential area, it will be classified and billed at the Residential Delivery rate.
Stay Reachable: Please provide a valid phone number. Carriers often need to coordinate delivery windows; missed connections can lead to significant delays.

2. Order Consolidation

To get your parts to you as fast as possible, we ship items as they become available. This means your order may arrive in multiple packages. Rest assured, you will never be charged extra for these split shipments.

3. Our Logistics Network

We partner with world-class carriers, including UPS, FedEx, DHL, USPS, and Amazon Logistics.

Global Fulfillment: We fulfill orders from our strategic hubs in the U.S. and Hong Kong, prioritizing the location closest to you.
Lead Times: While most orders arrive within 5–15 business days, specialty items or factory-direct shipments may require additional transit time.

4. Damaged or Missing Shipments

Your satisfaction is our priority. If your order arrives compromised, please follow this protocol:

For Damaged/Incomplete Deliveries:

Document Immediately: Note any visible damage or missing pieces on the delivery receipt before signing.
Contact Us: Reach out within 2 business days at service@DieselPerf.com or via phone at +1 325-013-1608 / +852 5381 0098.
Preserve Evidence: Keep all original packaging and take clear photos of the damage to expedite your claim.

For Lost Shipments:
If a package goes missing, we will initiate a dock check with the carrier (typically taking 2–7 business days). If the items cannot be located, we will work with you to provide a full replacement or a refund.

5. Estimated Timeframes

Processing: Orders are generally dispatched from our warehouse within 1–2 business days.
Transit: Standard U.S. ground shipping typically takes 7–10 business days, though many items arrive sooner.
Holiday & External Factors: Please account for seasonal peaks (Christmas, Thanksgiving, etc.) and unforeseen "Force Majeure" events like extreme weather, which may naturally extend delivery windows.

Customer Support

Our team is here to help you get back on the road.

Hours: Monday – Friday | 9:00 AM – 6:00 PM
Email: service@DieselPerf.com

All Dieselperf products enjoy a 1-year limited warranty starting from the date of goods receipt, covering defects in product materials and workmanship.

Warranty Coverage

This warranty only covers failures arising from original material and manufacturing defects under proper installation and normal use. The warranty is non-transferable and exclusively available to the original buyer. An order number or valid purchase receipt is mandatory for warranty claims.

Warranty Exclusions

The 1-year limited warranty does not apply to the following circumstances:

Normal wear and tear and surface scratches generated during regular use
Damage caused by improper installation, unauthorized disassembly or modification
Damage resulting from misuse, accidental impact, negligence and natural disasters
Natural aging loss of consumable spare parts
Labor costs incurred from product disassembly, assembly and maintenance

Warranty Claim Process

Submit Application: Email customer service with your order number, detailed fault description and clear photos or videos of product defects.
Claim Review: Our technical team will verify the issue. Additional information or product return inspection may be required.
Settlement Solutions: Upon claim approval, we reserve the right to take one of the following measures:

Repair the defective product
Replace with a brand-new authentic item
Deliver compatible replacement parts for repair

Limitation of Liability

Within the scope permitted by law, Dieselperf shall not be responsible for any special, incidental, indirect or consequential losses, including but not limited to profit losses, business suspension losses and other economic damages.