Wehrli 3-Inch Down Pipe — 2004.5-2010 Chevrolet 6.6L LLY/LBZ/LMM Duramax
Maximize exhaust flow and unleash the potential of your 2004.5-2010 Chevrolet Duramax with the Wehrli Custom Fabrication 3-Inch Down Pipe for LLY, LBZ, and LMM engines. The factory down pipe is a well-known restriction on these Duramax platforms, throttling turbocharger performance and elevating exhaust gas temperatures under load. Wehrli's mandrel-bent 3-inch down pipe removes this bottleneck, delivering measurable improvements in spool response, power output, and EGT reduction.
Key Features
- 3-inch diameter down pipe — major improvement over the restrictive OEM unit
- Covers LLY (2004.5-2005), LBZ (2006-2007), and LMM (2007.5-2010) Duramax engines
- Mandrel-bent for smooth, continuous exhaust flow with no pinch points
- Reduces exhaust back pressure for faster turbo spool and more power
- Lowers EGTs under towing and performance driving conditions
- Precision-fit for the Duramax turbocharger outlet to downpipe connection
- Built by Wehrli Custom Fabrication — trusted name in diesel performance
One Pipe, Three Generations of Duramax
Wehrli engineered this down pipe to cover the LLY, LBZ, and LMM Duramax platforms — three of the most popular diesel performance generations. Whether you're running a stock tune or a full performance build, this down pipe is an essential first step in improving your Duramax's exhaust system.
Fitment: 2004.5-2010 Chevrolet 6.6L LLY / LBZ / LMM Duramax
Part Number: WCF100120
Brand: Wehrli Custom Fabrication (WCFab)