WEHRLI CUSTOM FAB WCF100121 3IN DOWN PIPE (V-BAND STYLE) FOR 11-15 CHEVROLET 6.6L LML DURAMAX

Wehrli WCF100121 3" V-Band Down Pipe for 11-15 LML Duramax

The WEHRLI WCF100121 3" Down Pipe (V-Band Style) for the 2011-2015 Chevrolet 6.6L LML Duramax replaces the restrictive, crushed factory down pipe with a full 3" mandrel-bent unit designed for improved exhaust flow and lower exhaust gas temperatures (EGTs). Built for use with the factory turbocharger or factory-style drop-in turbos, this down pipe is a must-have upgrade for unlocking horsepower and response on your LML.

Featuring a V-band style connection at the outlet, this pipe is tailored to trucks equipped with the 2011-2014 style V-band exhaust system and 2015 trucks that retain that style of exhaust. It delivers the quality and fitment you expect from Wehrli Custom Fabrication (WCFab) in a race-ready package.

Key Features & Benefits

• Replaces the restrictive, crushed factory down pipe with a full 3" mandrel-bent design.
• V-band style outlet connection to match 2011-2014 LML exhaust systems and compatible 2015 setups.
• Designed for use with factory turbo or factory-style drop-in replacement turbochargers.
• Improves exhaust flow for quicker turbo spool, reduced EGTs, and increased performance potential.
• Includes heat wrap and clamps to help manage underhood temperatures and protect nearby components.
• High-quality construction and fitment from Wehrli Custom Fabrication, Made in the USA.
• Great foundation upgrade for future tuning, intercooler piping, and turbo system modifications.

What's Included

• Wehrli WCF100121 3" V-band style down pipe for 6.6L LML Duramax.
• High-temp exhaust heat wrap.
• Heat wrap clamps / ties.
• V-band style connection for OE-style LML exhaust (where applicable).

Vehicle Fitment

Designed specifically for GM LML Duramax pickup applications:

• 2011-2015 Chevrolet Silverado 2500HD / 3500HD 6.6L LML Duramax (V-band style down pipe exhaust)
• 2011-2015 GMC Sierra 2500HD / 3500HD 6.6L LML Duramax (V-band style down pipe exhaust)

Important flange note: 2015.5 and newer LML trucks use a 3-bolt flange style exhaust from the factory. This WCF100121 V-band style down pipe will only work if the truck has been converted to, or is using, the 2011-2014 style V-band exhaust system. For true 3-bolt flange 2015.5-2016 trucks, see the Wehrli 3-bolt stainless down pipe WCF100705 instead.

Compatibility & Use

• For use with factory turbocharger or factory-style drop-in turbo upgrades.
• Retains placement of factory exhaust aftertreatment components when used in compliant systems.
• Ideal for performance builds that want better flow while maintaining OE-style layout.
• Intended for off-road / race / competition use where applicable regulations permit. Always verify local emissions laws.

Installation & Tech Notes

• Direct replacement for the factory down pipe in 2011-2014 LML V-band style exhaust systems, and in 2015 trucks configured with V-band style exhaust.
• Removing the OEM crushed down pipe typically involves working around tight firewall and engine bay clearances; professional installation is recommended.
• After installation, verify that all clamps are tight, that the pipe clears wiring and hoses, and that there are no exhaust leaks.
• For 2015.5-2016 LML trucks with the 3-bolt flange exhaust, use Wehrli Stainless 3" 3-bolt down pipe PN: WCF100705, available at CPP Diesel, instead of this V-band style pipe.

Recommended Wehrli & CPP Diesel Upgrades for 2011-2016 LML

Build a complete, high-flow LML package by pairing the WCF100121 3" Down Pipe with these complementary Wehrli upgrades available from CPP Diesel:

• WEHRLI WCF100705 15.5-16 CHEVROLET 6.6L LML DURAMAX 3IN STAINLESS DOWN PIPE (3 BOLT FLANGE) – the correct choice for 2015.5-2016 LML trucks with the 3-bolt flange exhaust connection.
• WEHRLI WCF100328 2011-2016 LML DURAMAX PASSENGER SIDE UPPER CROSSOVER INTERCOOLER PIPE KIT – high-flow passenger side intercooler crossover pipe to reduce restriction and improve intercooler efficiency.
• WEHRLI WCF100682 11-16 DURAMAX LML PASSENGER SIDE 3.5 IN. INTERCOOLER PIPE – large-diameter aluminum intercooler pipe for increased boost handling and airflow.
• WEHRLI WCF100402 6.6L LML DURAMAX HIGH PRESSURE LINE CP3 CONVERSION KIT – upgrade your high-pressure fuel system when converting from CP4 to CP3 for improved reliability.
• WEHRLI WCF 100132 2011-2016 LML DURAMAX WCFAB X PPE HIGH CAPACITY CAST ALUMINUM ENGINE OIL PAN – add oil capacity and cooling to support higher power levels on your LML build.

Specifications

FAQ

The larger 3" mandrel-bent design removes the crushed, restrictive factory down pipe, improving exhaust flow, helping the turbo spool quicker, and typically lowering EGTs. It also provides a better foundation for future tuning and performance upgrades.

2015.5-2016 LML trucks use a 3-bolt flange style exhaust from the factory. This WCF100121 is a V-band style down pipe and will only fit those later trucks if the exhaust has been converted to the earlier 2011-2014 V-band style system. For true 3-bolt flange trucks, use Wehrli PN WCF100705 instead.

The down pipe itself does not inherently require tuning, but any time you alter exhaust restriction on a turbo diesel, it's best practice to run proper tuning that takes the overall setup into account. Many owners pair this upgrade with custom tuning for optimum driveability and performance.

Yes. The WCF100121 is designed for use with the factory turbocharger or factory-style drop-in turbos that retain OEM-style mounting and location. For custom turbo kits, verify down pipe compatibility with your turbo kit manufacturer or installer.

Emissions laws vary by region. Because this down pipe changes the factory exhaust layout, it may be restricted to off-road, race, or competition use only in some areas. Always check and follow your local, state, and federal regulations before installing on a street-driven vehicle.