6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2025

6.6L Duramax L5P 5 Inch Downpipe-Back Exhaust System | 2017–2025Introduction Unlock the full potential of your Chevrolet Silverado or GMC Sierra 2500 3500HD 6. 6L Duramax L5P with the Downpipe Back Race Exhaust System, available for 20172019 and 20202025 models. Built from 16 gauge stainless steel and offered in 4 inch or 5 inch variants. This L5P downpipe back exhaust delivers unrestricted flow, improved throttle response and a deep aggressive tone purpose built for serious off road and competition use. Available

Introduction

Unlock the full potential of your Chevrolet Silverado or GMC Sierra 2500/3500HD 6.6L Duramax L5P with the Downpipe-Back Race Exhaust System, available for 2017–2019 and 2020–2025 models. Built from 16-gauge stainless steel and offered in 4-inch or 5-inch variants. This L5P downpipe back exhaust delivers unrestricted flow, improved throttle response and a deep aggressive tone purpose built for serious off-road and competition use.

Available Variants

• 2017–2019 GM 2500/3500HD Duramax L5P
• 2020–2025 GM 2500/3500HD Duramax L5P

Both versions feature a 4” or 5” stainless steel configuration designed to fit each model generation precisely.

Features

• 16-gauge stainless steel construction for strength and corrosion resistance
• 4” and 5” diameter options to tailor flow, tone and application
• Downpipe-back race exhaust design for maximum airflow and power
• OEM-style hangers and prewelded contour bends for accurate fitment
• Improved flanges and stainless clamps for secure, leak-free connections
• OEM-style 4-bolt turbo flange (2020–2025 variant only)
• No bungs for a clean, unrestricted exhaust path
• Fits EC-CC/SB-LB-Dually configurations (not for Cab & Chassis trucks)
• Ease of installation with all necessary hardware included

Benefits

• Boosts horsepower and torque by reducing exhaust restriction
• Lowers EGTs during towing and heavy load operation
• Improves turbo spool and throttle response
• Enhances airflow for better engine breathing and efficiency
• Produces a deep, performance-driven exhaust tone
• Built from premium stainless steel for long-term durability in harsh conditions

Compatibility

• 2017–2019 Chevrolet Silverado / GMC Sierra 2500HD–3500HD 6.6L Duramax L5P
• 2020–2025 Chevrolet Silverado / GMC Sierra 2500HD–3500HD 6.6L Duramax L5P
• Fits EC-CC/SB-LB-Dually trucks
• Not compatible with Cab & Chassis models
• 2020–2025 models must have OEM-style 4-bolt turbo flange

Technical Specifications

• Material: 16-gauge stainless steel
• Diameter: 4” or 5” mandrel-bent tubing
• Configuration: Downpipe-back, single side exit
• Finish: Natural brushed stainless
• Hardware: Stainless clamps, contour-bent hangers, prewelded flanges
• Design: Bung-free, high-flow race system

Installation & Notes

• Direct bolt-on installation using factory hanger points
• No cutting or welding required
• Must be paired with off-road race tuning for proper performance
• Professional installation recommended for best results
• For off-road and race applications only

Frequently Asked Questions

Q1: What sizes are available?
A1: Choose between 4-inch or 5-inch stainless steel versions.

Q2: Does it require tuning?
A2: Yes. Race tuning is required for correct performance and to prevent error codes.

Q3: Are all components included?
A3: Yes. Each kit includes clamps, contour-bent hangers and improved flanges.

Q4: How does it change sound and performance?
A4: Expect a deeper exhaust tone, faster turbo spool, lower EGTs and improved throttle response.