PPE 117000600 – 3" 304 Stainless Steel High-Flow Downpipe for 2011–2015 LML Duramax

Upgrade the most restrictive part of your LML exhaust. The factory downpipe uses a crushed oval, crimped design with an abrupt turn right off the turbo. That chokes flow, raises EGTs, and slows spool. PPE’s 3-inch mandrel-bent 304 stainless steel downpipe replaces it with a smooth, round, unrestricted path.

Why it matters

• Lower EGTs and better turbo efficiency
• Quicker spool and improved response
• Reduced backpressure for more usable power and torque
• Deeper, throatier exhaust note
• Better heat control under the hood

Built from corrosion-resistant 304 stainless with TIG-welded, fully machined flanges for a leak-free fit. It retains the factory sensor ports (2× M20-1.5 and 1× M14-1.5) so OEM sensors and injectors stay in place. A woven titanium heat sleeve, secured with stainless clamps, helps keep under-hood temperatures down.

Key features

• 3" mandrel-bent 304 stainless steel construction
• Smooth, full-diameter flow path (no oval crush or indentations)
• TIG-welded, machined upper and lower flanges
• Woven titanium heat wrap with stainless clamps
• Factory sensor/injection ports retained
• Compatible with stock or PPE up-pipes
• CARB EO D-701-30 — 50-state legal
• Direct bolt-on replacement (OEM ref. GM 12643610)
• 3-year manufacturer warranty

Fitment 2011–2015 Chevrolet Silverado / GMC Sierra 2500HD & 3500HD with 6.6L Duramax LML.

Important: This part is for V-band / clamp-style connections. Early 2015 trucks typically use the V-band. Later 2015 trucks with a 3-bolt triangular flange need PPE 117000700. Verify your flange before ordering.

A simple, high-quality drop-in that lets the LML breathe the way it should.