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 11-15.5 6.6L Duramax LML is an incredible workhorse, but it is notorious for being heavily strangled by its complex first-generation DEF/SCR and DPF/CAT emissions systems. As these trucks age, the factory DPF ceramic core plugs up permanently with non-burnable ash.
- This results in your truck entering endless Active Regeneration cycles, which forcefully dumps raw diesel into the exhaust stroke just to heat up the filter.
- Your fuel economy tanks to a miserable 13-14 MPG, your EGTs skyrocket, and the immense backpressure puts extreme fatigue on turbocharger, frequently dropping the truck into Limp Mode.
Key Features
- True 4" Mandrel-Bent Flow: CNC mandrel-bent 4" T-409 SS tubing ensures smooth, high-velocity exhaust flow. Completely unrestricted with No Bungs to interrupt the air path.
- Massive Fuel Mileage Gains: Eliminates the fuel-hungry active regeneration process. Most LML owners see fuel economy recover from a clogged 13 MPG up to a clean 18-19 combined MPG on the highway.
- Drastic EGT & Backpressure Relief: Allows hot exhaust gases to escape instantly right out of the downpipe. This reduces structural heat-soak and lowers EGTs, protecting your turbocharger under heavy towing loads.
- Retain Factory Muffler: Replaces only the choked emission center sections. By keeping stock rear tailpipe and muffler, truck maintains a near-stock sound profile—slightly deeper, but completely free of annoying highway cab drone.
FAQ
Q: Can I keep my factory muffler with this pipe?
A: Yes. Because it replaces only the center section, your stock muffler and tailpipe stay intact. The sound remains nearly stock—silent and drone-free at highway speeds. (Note: To replace the full system quietly, choose 4“ muffler).
Q: Will this stop my truck's DEF system from throwing codes and failing?
A: Yes. Paired with a Minimaxx Tune, your entire DEF/SCR system deactivates in the software. The injector, tank heater, and NOx sensors stop cycling—ending DEF-related fault codes and countdown timers forever.
Q: Will this delete pipe fix the common LML CP4 fuel pump problem?
A: No. This pipe only resolves exhaust backpressure and emissions issues. However, because the factory CP4 fuel pump has a high failure rate on 11-16 trucks, many owners combine this upgrade with an LML CP3 Conversion Kit to protect their fuel system from catastrophic pump failure.
Q: How is this different from the full downpipe-back system?
A: This section pipe replaces only the under-cab DPF and CAT, letting you reuse stock downpipe and tailpipe. A Full DP-Back system replaces the entire line from turbo to tailpipe. If your factory downpipe and tailpipe are in good condition, this section pipe is a much more affordable choice.
