GM Duramax 6.6L Down-pipe Back Race Exhaust (2001-2007)
Type: Exhaust Systems | Fits: GM Duramax

Upgrade your Duramax with aΒ 4" or 5" Downpipe-Back Race Exhaust System designed to maximize exhaust flow and off-road performance. Built from high-grade stainless steel, this system removes restrictive factory components, improving power, throttle response, and fuel efficiency while reducing exhaust gas temperatures (EGTs). Perfect for competitive and heavy-duty applications.
Vehicle Fitment
- 2001β2007 Chevrolet Silverado 2500HD/3500HD 6.6L Duramax LB7, LLY, LBZ
- 2001β2007 GMC Sierra 2500HD/3500HD 6.6L Duramax LB7, LLY, LBZ
- Not compatible with Cab & Chassis trucks
Whatβs Included
- Choice of 4" or 5" stainless steel downpipe-back system
- All clamps and hardware for installation
- OE-style hangers for secure fitment
- Optional 4" or 5" muffler (for sound control)
Key Features
- 4" or 5" Stainless Steel Construction β Long-lasting durability and corrosion resistance.
- Downpipe-Back Design β Maximum flow by removing restrictive factory components.
- OE-Style Hangers β Simplifies installation and ensures a secure fit.
- No Bungs β Clean design optimized strictly for off-road use.
- Fuel Efficiency Boost β Increased airflow improves combustion efficiency.
Benefits
- Removes catalytic converter & DPF filter for unrestricted exhaust flow.
- Supports higher horsepower and torque output.
- Reduces EGTs for better performance under heavy load.
- Enhances throttle response and turbo spool-up.
- Available in multiple sizes for driver preference (4" for balance, 5" for max flow & sound).
Installation
This exhaust system is a direct-fit downpipe-back replacement for the OEM exhaust but requires race tuning after installation to function properly. While the kit includes all clamps and hardware, some modifications may be necessary depending on your truck configuration. Professional installation is strongly recommended for optimal results.
Important Notes:
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Important Notices
- OffβRoad Use Only
Products sold by JS Speed are intended for offβroad use and may be illegal on public roads where emissions or pollutionβcontrol 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 vehicleβs 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.



