FITMENT
- 2015.5-2016 6.6L Silverado & Sierra Duramax 2500HD/3500HD LML engine models with the 3-bolt flange.
- Does NOT Fit 2011-2015.5 model with the V-Band Clamp style.
- Please physically inspect underneath your truck to verify your turbo discharge style before purchasing!
DESCRIPTION
Product Overview
- In mid-2015.5, GM updated the 6.6L Duramax LML downpipe connection to a 3-hole triangular flange. Installing an earlier LML pipe on a 2015.5–2016 model results in severe fitment issues and exhaust leaks. Additionally, running a completely open straight pipe on these late LML trucks can cause intense cabin drone during highway towing.
- The 5" LML DPF Delete Pipe is engineered specifically for late-model LML trucks. The integrated high-flow straight-through performance muffler flushes out intense backpressure and lowers towing EGTs while keeping the exhaust tone deep, refined, and completely drone-free inside the cab.
Key Features
- Premium Material: Full 5-inch mandrel-bent T409 stainless steel tubing built to resist extreme thermal stress, road salt, and harsh winter corrosion.
- Substantial Towing EGT Reduction: Relieves intense backpressure directly behind the downpipe, allowing scorching gases to exit rapidly to protect your turbo and engine under heavy towing.
- Permanently Stop DEF Limp-Mode Errors: Eliminates failure-prone DEF heaters, pumps, and NOx sensors that trigger automatic Limp Mode lockouts.
- Full Downpipe-Back System: Replaces the entire restrictive mid-section and rusted OEM tailpipe from the turbo downpipe flange all the way to the rear exhaust exit.
FAQ
Q: What is the sound and performance difference between a 4" and a 5" Downpipe-Back kit on a 2015.5–2016 LML
A: 4" pipe is easier to install, keeps low-end exhaust velocity high for daily driving, and retains a tighter chassis fit. A 5" full system is built for high-horsepower setups seeking maximum flow, lowest EGTs, and a much louder, deeper V8 rumble.
Q: Will this 5" pipe clear my rear axle, shocks, and spare tire?
A: Yes. The rear axle over-bend tubing is CNC mandrel-bent to follow GM's OEM routing contours, leaving safe clearance around the rear axle, shock absorbers, and factory spare tire.
Q: How much weight will I save by replacing the full OEM exhaust on my 2015.5–2016 LML?
A: The heavy OEM emissions mid-section and restrictive stock tailpipe combined weigh over 85–90 lbs. Installing this lightweight 5-inch T409 stainless steel full system shaves off over 50+ lbs of unnecessary underbody dead weight.
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.
