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AFE 49-04003 ATLAS 4" Downpipe-Back Race Exhaust System

2011-2015 GM 6.6L Duramax LML
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The AFE 49-04003 ATLAS 4" Downpipe-Back Race Exhaust System for your 2011-2015 GM 6.6L Duramax is engineered to perform in the most extreme environments. This race exhaust system is constructed from precision, mandrel bent 4 aluminized steel tubing for maximum flow, increased horsepower, increased torque and lower EGTs. The 2-piece tailpipe and bayonet style hangers provide a hassle-free installation. To provide a leak-free seal, OE style band clamps are used that offer a 360º sealing area vs. cheap U-bolt clamps used in other systems. A 12" free-flowing straight-through designed muffler is used to produce a deep, powerful sound. Systems are available in 4 turbo back or 4 down pipe back with or without muffler. ATLAS exhaust systems are the perfect combination of performance, fit and value.

Installation is a Snap:
ATLAS exhaust systems utilize a 2-piece tailpipe design for a perfect fit by allowing adjustability at the tailpipe section. All systems use factory mounting locations providing stability and hassle-free installation.

Leak-Free Seal:
High quality OE style band clamps are used for a complete 360º sealing surface. Standard U-bolt clamps used by other systems only seal at the bottom and top of the tube allowing leak paths.

Aggressive Sound:
A free-flowing 12" wide muffler is used to absorb high pitch tones producing a powerful sound and unleashing all available horsepower and torque out of your rig.

Perfect Fit:
OE style bayonet hangers are used to maintain a stable pipe location during high vibration and high heat conditions. The Bayonet tip holds the hanger bushing in place for an OE style fit that does not change with time.

Flow and Performance:
ATLAS exhaust systems are constructed of precision, mandrel bent 4" aluminized steel tubing for maximum flow. Smooth transition bends allow for low turbulence, increasing horsepower, torque and lowering EGTs.

System Options
With Muffler 49-04003
Without Muffler 49-04003NM

Fitment Note: This exhaust will only fit 2015 models manufactured before July 2014. Models built after July of 2014 are equipped with a 3-bolt down pipe flange connection that is not compatible with this product.

Warning: This free-flow race exhaust system requires the use of an aftermarket performance programmer with off-road tuning.

Product Options

49-04003 With Muffler


  • Manufacturer Name AFE
  • Shipping Weight 75.00 lb.
  • Shipping Length 60 in.
  • Shipping Width 19 in.
  • Shipping Height 14 in.
  • UPC 802959490860
  • Warranty Yes
  • Warranty Info 2 Year
  • Prop 65 WARNING: Cancer & Reproductive Harm -


Buy extra clamps
Austin price
Location: Louisiana
Just as the headline reads. The exhaust clamps or made below China. Snap everyone. Didn't even get tight enough till they broke.

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Questions and Answers

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Most Popular Questions

Will this fit a 2011 Silverado 3500 CCLB dually? I didn't know if there is an exhaust length difference between cab configurations and bed configurations. I assume there is but I didn't see where this is addressed when ordering.
View Staff Answer 
The AFE ATLAS Aluminzed Exhaust System 49-04003 (Downpipe-Back) will fit all cab and bed configuraditons.
Will this set off any exhaust sensors?
View Staff Answer 

The AFE 49-04003 ATLAS 4" Downpipe-Back Race Exhaust System must be run with an aftermarket performance programmer with off-road tuning.

Will this fit a Chevy Express Van?
View Staff Answer 

No it will not. The AFE 49-04003 ATLAS 4" Downpipe-Back Race Exhaust System will only fit the 11-15 Duramax pickups.

Emissions Notice

This product is not legal for sale or street use in California. Certain aftermarket products are subject to governmental emission standards regulated by the California Air Resources Board. In order for these products to be legal on a specific vehicle in California, the part number must receive a CARB Executive Order (EO) number. This number makes the part legal for use only on specific years, makes and models of vehicles. A decal with CARB EO number for these parts must be displayed in the engine bay to satisfy smog inspection requirements.