GM Duramax L5P 6.6L Downpipe-Back Exhaust System (2017-2025)
Type: Exhaust Systems
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 pre-welded 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.
Important Notes:
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Important Notices
- Off‑Road Use Only
Products sold by JS Speed are intended for off‑road use and may be illegal on public roads where emissions or pollution‑control laws apply. - Check Local Laws
Before purchasing or installing, verify all applicable local, state/provincial, and federal regulations to ensure the modification is legal in your area. - Professional Installation Recommended
These parts should be installed by qualified professional mechanics. Improper installation can cause performance issues or vehicle damage. Unless a product page explicitly states otherwise, installation instructions are not included. Components are designed for users with solid mechanical knowledge, and minor adjustments or modifications may be required for proper fitment. Returns or refunds cannot be accepted due to difficulty completing an installation or the absence of instructions. - Warranty Impact
Use of these parts may void your vehicle’s factory warranty. Confirm with your vehicle manufacturer before purchase and installation. - Limitation of Liability
JS Speed is not responsible for damage, failures, or issues arising from the use or installation of these products. - Product Images
Images are for illustration only and may differ from the actual product due to manufacturer updates or improvements. - No Performance Guarantees
While these products are designed to enhance performance, JS Speed does not guarantee specific performance results.
