GM Duramax 6.6L Down-pipe Back Race Exhaust (2001-2007)

This 4-inch or 5-inch downpipe-back race exhaust system is designed for Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks equipped with the 6.6L Duramax LB7, LLY, or LBZ engines.

The system replaces the exhaust from the downpipe back to reduce restriction and improve exhaust flow. The larger diameter piping helps lower backpressure, supporting better turbo response and more consistent power delivery.

Vehicle Compatibility

• Years: 2001-2010
• Makes: Chevrolet Silverado, GMC Sierra
• Models: 2500, 3500HD
• Engine: 6.6L Duramax LB7/LLY/LBZ (diesel)
• Body: Pickup

Technical Specifications

This exhaust system is available in 4-inch or 5-inch diameter options and is built from mandrel-bent stainless steel for smooth airflow and long-term durability. The layout runs from the turbo downpipe back to the tail section, replacing the full exhaust path. The kit includes band clamps, hangers, and all required installation hardware. It is designed for race-only use, with no sensor bungs included. In terms of sound, the 5-inch system flows more air and is louder than the 4-inch option; a muffler can be added if reduced exhaust noise is preferred.

Seamless Installation Process

The Downpipe-Back Exhaust for Duramax LB7 LBZ is exclusively crafted for off-road usage. Unlock its full potential with race tuning for peak performance. The package includes all essential clamps and hardware for a bolt-on installation with basic tools; however, cutting of old hardware may be required. For optimal outcomes, professional installation is advised to ensure precise tuning and fit.