FITMENT
- 2011-2015.5 6.6L Silverado & Sierra Duramax 2500HD/3500HD LML engine with a V-Band Clamp.
- Does NOT Fit 2015.5-2016 models equipped with the 3-bolt flange. Please check underneath your truck!
- Please physically inspect underneath your truck to verify your turbo discharge style before purchasing!
DESCRIPTION
Product Overview
- The 6.6L Duramax LML features a heavy, highly restrictive factory emissions mid-section and necked-down tailpipe that trap extreme thermal heat behind the turbo housing. These restrictive components trigger constant fuel-wasting active regens, raise towing EGTs, and cause DEF sensor failures that lock your work truck into Limp Mode.
- The 5" LML Turbo Downpipe-Back Race Exhaust Kit is a complete, unhindered exhaust solution. By dropping system backpressure to near zero, it sharply lowers towing EGTs, restores fast turbo spool-up, improves fuel economy by 2–3 MPG, and delivers an aggressive, deep V8 diesel tone.
Key Features
- Premium Material: Full 5-inch mandrel-bent T409 stainless steel tubing built to resist thermal expansion, road salt, and harsh winter chassis rust.
- Unleash Unmistakable V8 Turbo Sound: Removes all restrictive emissions baffles to restore a deep, throaty diesel V8 roar and crisp turbo spool whistle under acceleration.
- Sharply Drop Towing EGTs: Flushes out extreme exhaust backpressure right behind the turbo downpipe, allowing hot exhaust gases to exit rapidly to protect your LML V8 during heavy towing.
- Permanently Eliminate DEF & DPF Errors: Stops failure-prone DEF heaters, pumps, and NOx sensors that trigger automatic 55-MPH dealer Limp Mode lockouts.
FAQ
Q: What is the main difference in sound and performance between a 4" and 5" Downpipe-Back kit on an LML?
A: 4" pipe is easier to install, keeps your stock tailpipe layout, and preserves low-end towing torque for daily street tunes. A 5" full system is built for high-horsepower setups seeking maximum flow, lowest EGTs, and a much louder, deeper V8 rumble.
Q: Does this 5" full kit include an exhaust tip, or do I need to buy one separately?
A: The system terminates with a clean, raw 5-inch outer diameter (OD) stainless steel tailpipe. It does not include a decorative tip, but it is ready to accept any standard aftermarket clamp-on or bolt-on exhaust tip.
Q: Will installing a 5" straight-pipe exhaust noticeably increase turbo spool-up and throttle response?
A: Absolutely. By eliminating the heavy, clogged factory DPF, CAT, and SCR canisters, turbine backpressure drops to near zero. This allows your turbocharger wheel to spool up much faster, giving you crisp throttle response when accelerating or passing under load.
Q: Do I need a custom delete tuner to run this 5" Downpipe-Back exhaust on an LML Duramax?
A: Yes. Factory LML DEF heaters and NOx sensors frequently fail, triggering a countdown that locks your truck into a Limp Mode. Removing the emissions system with a custom ECM tune completely bypasses these sensors, permanently eliminating limp-mode lockouts.
