Fits 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L L5P Duramax).

The Wehrli Custom Fabrication Aluminum Upper Coolant Pipe is a heavy-duty upgrade designed to replace the failure-prone factory rubber upper radiator hose. This aluminum pipe offers increased durability and a custom aesthetic for your engine bay, finished in a signature WCFab Red powder coat. It is a direct-fit replacement for GM Part Number 84094878, providing a more secure connection that resists expansion and degradation under heat and pressure.

• Replaces OEM GM Part Number: 84094878
• High-quality aluminum coolant pipe construction
• Durable custom WCFab Red powder coat finish
• Reinforced silicone boots for high-temperature performance
• Stainless steel T-bolt clamps for a leak-free seal
• Manufacturer Part Number: WCF100742-RED

Fits select 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD models (6.6L L5P Duramax).

Upgrade your engine bay’s reliability and aesthetics with the Wehrli Custom Fabrication (WCFab) Aluminum Upper Coolant Pipe. This kit is designed to replace the factory rubber upper coolant hose, which is prone to fatigue and failure over time. Constructed from high-quality aluminum tubing and finished in a durable Gloss White powder coat, this pipe provides a permanent solution that withstands the heat and pressure demands of the L5P Duramax engine.

This kit is a direct replacement for GM Part Number 84094878 and includes everything needed for a secure, leak-free installation, including reinforced silicone boots and heavy-duty stainless steel T-bolt clamps.

• Replaces factory rubber hose (GM Part No. 84094878)
• Mandrel-bent aluminum construction for improved durability
• Gloss White powder-coated finish for corrosion resistance
• Includes high-temperature silicone boots
• Includes stainless steel T-bolt clamps for a secure seal
• Manufacturer Part Number: WCF100742-GW

Fits select 2004-2016 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD trucks equipped with the 6.6L Duramax diesel engine (LLY, LBZ, LMM, and LML). This handmade VGT exhaust housing blanket is a direct-fit solution for stock and drop-in replacement turbochargers.

By containing up to 80% of radiant heat within the turbine housing, the Wehrli Custom Fabrication (WCFab) heat blanket significantly reduces under-hood temperatures and protects sensitive engine components. Retaining this thermal energy maintains exhaust gas velocity, which improves turbine efficiency and reduces turbo lag for faster spool-up. Designed for extreme performance, the internal ceramic insulation is rated to withstand direct heat sources exceeding 2,500°F.

• Replaces or covers the factory turbo housing to improve thermal management.
• Hand-crafted in the USA with a durable grey high-temperature exterior shell.
• Internal wire mesh layer provides maximum abrasion resistance against engine vibration.
• Stainless steel rivet fasteners ensure a secure, tight fit around the VGT housing.
• Compatible with LLY, LBZ, LMM, and LML engine codes.
• Note: Not compatible with metal OEM turbo heat shields.
• Manufacturer Part Number: WCF100733

Protect your engine bay and optimize turbocharger efficiency with the Wehrli Custom Fabrication Universal T6 Exhaust Housing Heat Blanket (WCF100732). By containing thermal energy within the exhaust housing, this blanket maintains high exhaust gas velocity for improved spool-up while significantly reducing under-hood temperatures to protect sensitive electronics, hoses, and wiring.

Constructed for extreme duty, this blanket features a durable high-temperature exterior shell and internal insulation rated to withstand over 2500°F of direct heat. This universal T6 design is handmade in the USA and utilizes stainless steel rivet fasteners for a secure, professional installation on large-frame turbochargers.

• Compatible with S400, S500, GT50, GT55, and Precision T6 exhaust housings
• Internally rated for 2500°F+ direct heat exposure
• Reduces engine bay heat soak and protects surrounding components
• High-temperature exterior shell with stainless steel rivet fasteners
• Handmade in the USA
• Manufacturer Part Number: WCF100732

This Wehrli universal T4 exhaust housing heat blanket is engineered to insulate the turbocharger's hot side, retaining thermal energy within the housing to improve spool-up efficiency and significantly reduce under-hood temperatures. Designed for versatile fitment, it is compatible with all T4 flange exhaust housings found on S300, S400, Garrett, Holset, and Precision turbochargers.

• Internally rated to withstand over 2500°F of direct heat for extreme thermal management
• Durable high-temperature exterior shell provides long-lasting protection against heat soak
• Equipped with stainless steel rivet fasteners for secure and reliable installation
• Handmade in the USA to ensure high-quality construction and precise fitment
• Universal design fits a wide range of T4 flange-style turbochargers
• Manufacturer Part Number: WCF100731

Fits 2010-2024 Dodge and Ram 2500/3500 trucks (6.7L Cummins).

Clean up your engine bay by replacing the fragile, plastic factory covers for the EGR crossover tube and throttle valve with this heavy-duty engine cover from Wehrli Custom Fabrication (WCFab). Designed for both aesthetics and durability, this cover provides a custom look while standing up to the heat and vibration of the 6.7L Cummins platform.

Each cover is manufactured in the USA from 10-gauge aluminum, laser-cut, CNC-bent, and TIG-welded for precise fitment. The assembly features an integrated oil dipstick pass-through, allowing for easy maintenance without removing the cover. It finished in a durable Gloss White powder coat that resists automotive fluids and grime.

• Construction: 10-gauge aluminum, TIG-welded
• Finish: Gloss White powder coat
• Installation: Bolt-on with basic hand tools; no modifications required
• Includes: Installation hardware
• Replaces OEM Part Numbers: 4861984AA, 4869184AB, 68027072AA, 68358113AA
• Manufacturer Part Number: WCF100730-GW

Protect your engine and extend the life of your performance air filter with the Wehrli Custom Fabrication (WCF) Universal Outerwear Air Filter Cover. This pre-filter is specifically designed to fit WCF100717 4-inch and WCF100719 5-inch air filters, providing a critical secondary defense against moisture and heavy debris without sacrificing airflow.

The WCF100728 features a specialized hydrophobic treatment that causes water from puddle splashes or rain to bead off the surface. Beyond water resistance, the mesh is engineered to stop particles as small as .005 inches, preventing premature clogging of the main filter element. This is an essential upgrade for vehicles with exposed filters or those used in harsh environments like dirt tracks, pulling, or off-road driving.

• Compatibility: Specifically fits WCF100717 (4") and WCF100719 (5") air filters.
• Water Resistant: Hydrophobic treatment repels moisture (not waterproof; do not submerge).
• Advanced Filtration: Screens out debris down to .005".
• Durable Construction: Puncture resistant, UV resistant, and heat resistant up to 450°F.
• Maintenance: Clean with mild soapy water; do not scrub. Treatment lasts 6–12 months depending on conditions.
• MPN: WCF100728

To verify the hydrophobic coating is still active, perform a simple spray bottle test. If water beads off, the treatment is working; if water enters the mesh, it is time to replace the cover to maintain optimum engine protection.

Ensure your engine receives maximum protection and high-velocity airflow with the WCFab Universal 5in Inlet Dry Air Filter. Specifically engineered as the direct replacement filter for WCFab 5-inch air intakes, Twin Turbo, and S400 Single Turbo install kits, this filter utilizes a dry synthetic media that provides filtration efficiency comparable to cotton without the need for messy re-oiling.

• Manufacturer Part Number: WCF100719
• Inlet Diameter: 5 inches
• Filter Length: 11 inches
• Base Diameter: 7 inches
• Media Type: Dry (non-washable)
• Compatibility: WCFab 5" intakes, Twin Turbo kits, and S400 Single Turbo kits

Maintenance is straightforward: do not wash this filter. Use compressed air to blow debris from the pleats every 5,000 miles, maintaining a minimum 6-inch distance between the nozzle and the media. Under highway conditions, the filter provides a service life of up to 30,000 miles. Replace the filter immediately if pleats begin to collapse or if severe restriction is observed.

Fits select 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD models equipped with the 6.6L L5P Duramax diesel engine.

The WCFab High Flow Intake Bundle Kit is a Stage 1 upgrade designed to resolve factory airflow restrictions and eliminate failure-prone plastic components. This kit replaces the factory 2.5-inch diameter hot side intercooler pipe and the two-piece plastic/rubber cold side assembly with heavy-duty, one-piece mandrel-bent aluminum piping. By increasing the hot side to 3 inches and the cold side to 3.5 inches, this bundle improves turbo spool-up, throttle response, and overall engine efficiency.

Constructed in the USA from 14-gauge aluminum, these pipes feature a durable Gloss White powder coat finish. The hot side pipe eliminates the OEM resonator for better flow, while the cold side pipe utilizes a CNC-machined flange with a double O-ring seal to prevent the boost leaks common with the factory clip-ring design. This system is a direct bolt-on replacement that requires no aftermarket tuning.

• Manufacturer Part Number: WCF100718-GW
• Hot Side Pipe: 3-inch diameter mandrel-bent 14-gauge aluminum
• Cold Side Pipe: 3.5-inch diameter mandrel-bent 14-gauge aluminum
• Connection: CNC machined flange with double O-ring seal
• Hardware: High-temp reinforced silicone boots and stainless steel T-bolt clamps
• Installation: Bolt-on design using basic hand tools; retains factory sensors
• Finish: Signature Gloss White powder coat

Designed as the direct replacement filter for Wehrli Custom Fabrication 4-inch intake systems and S300 Turbo Single Install kits, the WCF100717 dry air filter provides high-efficiency filtration without the need for oil. This dry media filter is engineered to protect your engine from harmful debris while maintaining airflow levels comparable to high-performance cotton-gauze filters.

• Precision Fitment: 4-inch inlet diameter compatible with WCFab 4" intake kits and S300 Turbo Single Install Kits.
• Dry Media Technology: Provides exceptional engine protection and is specifically designed to be non-washable for simple maintenance.
• Service Life: Rated for up to 30,000 miles of highway use, depending on driving conditions.
• Construction: Heavy-duty pleats designed to resist collapsing under high-boost or high-vacuum applications.

Maintenance & Cleaning:
To maintain optimal performance, inspect the filter media every 5,000 miles. This filter is NOT washable; do not use water or cleaning solvents. To extend the service life between 15,000 to 30,000-mile replacement intervals, you can use compressed air to remove loose debris. Direct compressed air from the inside out, keeping the air nozzle at least 6 inches away from the media to prevent damage.

Fits select 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L).

The WCFab 3-inch High Flow Driver Side (Hot Side) Intercooler Pipe addresses a common weak point in the 2017-2019 L5P 6.6L Duramax drivetrain. This kit replaces the restrictive factory two-piece 2.5-inch intercooler pipe with a high-flow, one-piece 3-inch mandrel-bent tube. By increasing the diameter and smoothing the transition, this pipe improves airflow efficiency and turbocharger response.

Engineered for long-term reliability, this kit includes heavy-duty silicone boots designed to withstand higher boost pressures and temperatures than factory components, effectively eliminating the risk of blown boots during heavy towing or high-load conditions. The assembly is finished in a durable Gloss White powder coat for a premium under-hood appearance and installs as a direct bolt-on with no tuning or additional modifications required.

• Replaces GM Part Number: 87839947
• Manufacturer Part Number: WCF100708-GW
• 3-inch mandrel-bent one-piece construction
• Durable Gloss White powder coat finish
• Heavy-duty silicone boots and stainless steel T-bolt clamps included
• Direct bolt-on installation with no tuning required

Fits select 2017-2019 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD trucks equipped with the 6.6L L5P Duramax diesel engine.

Upgrade the restrictive factory charge air system with the Wehrli Custom Fab (WCFab) 3-inch High Flow Driver (Hot) Side Intercooler Pipe. This one-piece mandrel-bent 3-inch pipe replaces the restrictive two-piece 2.5-inch factory assembly, significantly improving airflow from the turbocharger to the intercooler. By eliminating the factory seams and joints, this kit reduces potential leak points and enhances turbo response.

Designed for maximum durability under high boost conditions, this kit includes heavy-duty silicone boots engineered to withstand higher temperatures and pressures than OEM components. The system installs as a direct bolt-on replacement with no tuning required and is finished in a durable gloss black powder coat for a clean, professional look under the hood.

• One-piece 3-inch high-flow mandrel-bent piping
• Replaces factory GM part number 87839947
• Upgraded heavy-duty silicone boots for increased pressure handling
• Stainless steel T-bolt clamps included for secure connections
• Durable gloss black powder coat finish
• No aftermarket tuning or modifications required
• Manufacturer Part Number: WCF100708-GB

Fits 2015-2016 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L LML Duramax).

The Wehrli Custom Fabrication (WCFab) 3" Stainless Steel Downpipe is designed to eliminate the restrictive, crushed factory downpipe found on 2015.5-2016 LML engines. By increasing exhaust flow directly from the turbocharger, this upgrade improves throttle response and helps maintain lower exhaust gas temperatures (EGTs). This downpipe is specifically engineered for trucks equipped with the 3-bolt flange exhaust connection and is compatible with the factory turbocharger or factory-style drop-in replacements.

• 3" diameter high-flow stainless steel construction
• Designed for 3-bolt flange exhaust connections
• Direct replacement for GM part numbers 12674630 and 12655717
• Includes high-temperature heat wrap and stainless steel clamps
• No ECM tuning required for installation
• Manufactured in the USA
• Manufacturer Part Number: WCF100704

Note: For 2011-2014 LML models with a V-band style connection, please see WCFab part number WCF100704.

Fits select 2011-2015 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD trucks (6.6L LML Duramax).

The Wehrli Custom Fabrication 3-inch Stainless Steel Downpipe is designed to replace the restrictive, crushed factory downpipe on LML Duramax engines. This high-flow replacement improves exhaust scavenging and reduces backpressure at the turbocharger. This specific model is designed for use with factory or factory-style drop-in turbochargers that utilize a V-band connection; it is not compatible with 3-bolt flange style exhausts.

• 3-inch diameter stainless steel construction for corrosion resistance and durability
• V-band style flange for a secure, leak-free connection
• Includes thermal heat wrap and heavy-duty clamps
• No ECU tuning or recalibration required for installation
• Direct replacement for GM part numbers: 12643610, 12638304, 12643214
• Note: If your vehicle requires a 3-bolt style downpipe, use MPN: WCF100705
• Made in the USA
• Manufacturer Part Number: WCF100704

Fits select 2004-2010 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD (6.6L).

Replace the restrictive, crushed factory turbo down pipe on your 6.6L Duramax Diesel V8 with this high-flow 3-inch stainless steel upgrade from Wehrli Custom Fabrication. Designed for 2004.5-2010 LLY, LBZ, and LMM engines, this down pipe improves exhaust flow and reduces heat soak thanks to the included pre-installed heat wrap. It is compatible with the OEM turbocharger or factory-style drop-in units and requires no aftermarket tuning for installation.

• Diameter: 3 inches
• Material: Stainless Steel
• Finish: Pre-installed heat wrap for superior thermal management
• Compatibility: 6.6L Duramax (LLY, LBZ, LMM)
• Direct Replacement for GM Part Number: 98050150
• Installation: No tuning required
• Manufacturing: Made in USA
• MPN: WCF100703

Package Includes: 3-inch stainless steel downpipe, pre-installed heat wrap, and clamps.

Fits select 2020-2025 Chevrolet Silverado and GMC Sierra 2500/3500 HD (6.6L L5P Duramax). This Wehrli Custom Fabrication (WCFab) 4" high-flow intake kit replaces the restrictive plastic factory components to improve engine efficiency and turbo response.

Built for the rigors of heavy-duty use, the kit features a large-diameter 4" fabricated aluminum intake pipe with smooth aerodynamic bends. The included air box and lid are constructed from durable 10-gauge aluminum sheet and feature a seal designed to connect directly to the functional hood ram air port, drawing in cooler, denser air from the hood duct and inner fender. This system provides a more aggressive turbo sound while maintaining a bolt-on installation that requires no aftermarket tuning.

• 4" large-diameter aluminum intake piping for improved air velocity
• Air box and lid constructed from 10G aluminum sheet
• Dry air filter assembly with Outerwear's pre-filter cover
• High-quality silicone boot and stainless steel T-bolt clamps included
• Gloss White powder coat finish for superior corrosion resistance
• No tuning required; compatible with stock vehicles
• Replaces GM part numbers: 84841229, 84841225, 84262962, 85614333, 84554702
• MPN: WCF100702-GW

Fits 2020-2025 Chevrolet Silverado and GMC Sierra 2500/3500 HD trucks equipped with the 6.6L L5P Duramax diesel engine.

The WCFab 4-inch High Flow Intake Kit replaces the restrictive factory plastic components with a high-performance fabricated aluminum assembly designed to maximize airflow and thermal efficiency. By utilizing the functional hood ram air duct and inner fender air path, this system delivers cooler intake temperatures and increased air volume to the turbocharger, resulting in improved throttle response and more aggressive turbo sound during acceleration.

Constructed from heavy-duty 10-gauge aluminum sheet metal, the air box and lid provide a robust, heat-shielded environment for the included dry air filter. The 4-inch intake piping features smooth, aerodynamic bends to maintain high air velocity. This is a true bolt-on upgrade that requires no ECM tuning and is compatible with stock vehicle configurations.

• 4-inch fabricated aluminum intake pipe for maximum volume
• 10-gauge aluminum air box and lid with functional ram air seal
• High-flow dry air filter with Outerwear's pre-filter cover
• Durable gloss black powder coat finish
• Premium silicone boot and stainless steel T-bolt clamps
• Replaces OEM Part Numbers: 84841229, 84841225, 84262962, 85614333, 84554702
• Manufacturer Part Number: WCF100702-GB

Designed for select GM vehicles, the Wehrli Custom Fabrication Billet Heater Core Fitting Kit (WCF100699) provides a robust solution to the common failure point of brittle, leak-prone plastic OEM heater core connectors.

This kit features a precision-machined billet aluminum quick-connect fitting that utilizes a wire retainer clip for secure, tool-free installation and removal. The internal serviceable O-ring seals ensure a leak-proof connection when installed with appropriate lubricant. Included is a preformed 1/2-inch universal heater hose assembly, engineered to maintain its shape and provide reliable coolant flow in demanding engine bay environments.

• Precision billet aluminum construction replaces fragile plastic factory fittings
• Preformed universal 1/2-inch heater hose assembly included
• Serviceable internal O-ring seals for long-term reliability
• Wire retainer clip allows for easy removal and installation without special tools
• Manufacturer Part Number: WCF100699

Fits 2011-2016 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD models (6.6L LML Duramax).

The Wehrli Custom Fabrication (WCFab) Aluminum Upper Coolant Pipe provides a durable, high-performance replacement for the factory rubber upper radiator hose. Designed to withstand the heat and pressure demands of the LML Duramax engine, this aluminum pipe eliminates the risk of hose expansion and failure. It features a custom two-stage powder coating in WCFab Red for long-lasting corrosion resistance and a clean engine bay appearance.

This kit is engineered for a direct fit with the OEM GM radiator. Please note that while it integrates seamlessly with factory cooling systems, some aftermarket radiators may cause fitment clearance issues.

• High-quality aluminum construction replaces prone-to-fail OEM rubber hoses
• Custom Two-Stage WCFab Red powder coated finish
• Includes heavy-duty silicone boots and stainless steel T-bolt clamps
• Compatible with factory GM radiators
• Installation instructions included
• Manufacturer Part Number: WCF100696-RED

Fits select 2011-2016 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD models (6.6L LML Duramax).

Replace the failure-prone factory rubber upper radiator hose with this heavy-duty aluminum coolant pipe from Wehrli Custom Fabrication. Unlike the OEM rubber hose that can soften and collapse over time, this mandrel-bent aluminum pipe maintains its structural integrity under pressure and adds a custom aesthetic to your engine bay with a Gloss White powder-coated finish.

This kit is designed for a direct-fit installation on vehicles equipped with the OEM GM radiator. It includes high-quality silicone boots and heavy-duty T-bolt clamps to ensure a leak-free seal. Please note that some aftermarket radiators may cause fitment issues due to varying inlet/outlet positions.

• Replaces factory rubber upper coolant hose
• Mandrel-bent aluminum construction
• Custom Gloss White single-stage powder coating
• Includes silicone boots and T-bolt clamps
• Designed for use with OEM GM radiator
• Manufacturer Part Number: WCF100696-GW

Fits 2011-2016 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L LML Duramax).

The Wehrli Custom Fabrication aluminum upper coolant pipe is a heavy-duty replacement for the failure-prone factory rubber upper coolant hose on LML Duramax engines. Constructed from high-quality aluminum and finished in a gloss black single-stage powder coating, this pipe provides superior durability and a clean, professional look under the hood.

This kit is designed specifically for use with the factory OEM GM radiator. Please note that some aftermarket radiators may cause fitment issues due to differences in inlet positioning. The package includes all necessary components for a secure installation, featuring high-temperature silicone boots and heavy-duty T-bolt clamps to ensure leak-free performance under pressure.

• Manufacturer Part Number: WCF100696-GB
• Material: Mandrel-bent aluminum pipe
• Finish: Gloss Black powder coat
• Replaces OEM rubber upper coolant hose
• Includes silicone boots and T-bolt clamps
• For use with OEM GM radiator

Fits select 2020-2025 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD models (6.6L L5P Duramax).

The WCFab Stage 2 4-inch intake kit replaces the restrictive plastic factory intake components with high-flow fabricated aluminum parts. Designed specifically for the L5P Duramax, this kit features a 10-gauge aluminum sheet air box and lid that seals to the functional hood ram air port and inner fender to draw in cooler, denser air. The oversized 4-inch intake horn is more than one inch larger than the OEM diameter, eliminating the significant restriction found at the factory turbo inlet.

This bolt-on assembly improves intake air velocity and volume, resulting in quicker throttle response and more aggressive turbo sound without the need for an aftermarket tune. Each kit is finished in a durable custom red powder coat and includes a dry air filter with an Outerwears pre-filter cover for maximum protection and maintenance-free performance.

• Replaces GM Part Numbers: 84841229, 84841225, 84262962, 85614333, 84554702
• Fabricated 10G aluminum air box and lid
• Mandrel-bent 4-inch aluminum intake pipe
• High-flow 4-inch intake horn removes turbo inlet restriction
• Dry air filter with Outerwears pre-filter cover
• Heavy-duty silicone boot and stainless steel T-bolt clamps
• No tuning required; direct bolt-on installation
• Made in the USA
• Manufacturer Part Number: WCF100684-RED

Fits 2020-2025 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L L5P Duramax).

Eliminate the restrictions of the factory plastic induction system with the Wehrli Custom Fabrication (WCFab) Stage 2 4-inch Intake Kit. This system replaces the entire OEM air path with large-diameter, fabricated aluminum piping and a high-flow 10G aluminum air box. Designed to interface directly with the factory hood Ram Air duct and inner fender ports, this kit ensures the turbocharger receives a consistent supply of cool, dense air for improved throttle response and increased air velocity.

The centerpiece of the Stage 2 kit is the 4-inch intake horn, which is over an inch larger than the OEM diameter, removing the primary bottleneck found at the turbo inlet. Finished in a signature Gloss White powder coat, this kit provides a custom look under the hood while maintaining a simple bolt-on installation that requires no aftermarket tuning.

• 4-inch fabricated aluminum intake pipe and intake horn
• 10-gauge aluminum air box and lid with functional hood duct seal
• High-flow dry air filter assembly with Outerwears pre-filter cover
• Heavy-duty silicone boots and stainless steel T-bolt clamps
• Durable Gloss White powder-coated finish
• Direct bolt-on replacement for GM Part Numbers: 84841229, 84841225, 84262962, 85614333, 84554702
• No tuning required; compatible with stock trucks
• Manufacturer Part Number: WCF100684-GW
• Made in the USA

Fits 2020-2025 Chevrolet Silverado and GMC Sierra 2500 HD/3500 HD (6.6L L5P Duramax).

The WCFab Stage 2 4in Intake Kit replaces the restrictive factory plastic intake components with a high-flow fabricated aluminum system designed to maximize turbo efficiency. This kit features a 4-inch diameter intake pipe and an oversized 4-inch intake horn that is over an inch larger than the OEM inlet, significantly reducing intake restriction. The included air box and lid are constructed from heavy-duty 10-gauge aluminum sheet and feature a custom seal that connects directly to the functional hood ram air port and inner fender duct for a steady supply of cool, dense air.

Built for durability and performance, this bolt-on system requires no tuning and utilizes high-quality silicone boots and stainless steel T-bolt clamps for secure connections. The assembly is finished in a durable Gloss Black powder coat. This kit replaces GM Part Numbers: 84841229, 84841225, 84262962, 85614333, and 84554702.

• Manufacturer Part Number: WCF100684-GB
• 4-inch diameter fabricated aluminum intake piping
• 4-inch oversized intake horn
• 10-gauge aluminum air box and lid
• High-flow dry air filter with Outerwears pre-filter cover
• Heavy-duty silicone boots and stainless steel T-bolt clamps
• Direct bolt-on installation; no tuning required
• Compatible with factory hood ram air port
• Made in the USA

Fits select 2020-2025 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD trucks (6.6L Duramax L5P).

The WCFab Stage 2 4-inch Intake Kit replaces the restrictive factory plastic induction system with a high-flow fabricated aluminum assembly. This kit features a 4-inch diameter intake pipe and an oversized intake horn that is over an inch larger than the OEM diameter, significantly reducing restriction at the turbo inlet. The included 10G aluminum air box and lid are designed to seal against the factory functional hood ram air port and inner fender, ensuring the engine draws in the coolest possible air for improved throttle response, increased horsepower, and lower intake temperatures.

• 4" fabricated aluminum intake pipe with smooth aerodynamic bends
• Oversized 4" intake horn to maximize air velocity at the turbo
• 10G aluminum sheet metal air box and lid
• High-flow dry air filter with Outerwears pre-filter cover
• Heavy-duty silicone boot and stainless steel T-bolt clamps
• Durable Candy Teal powder coat finish
• Direct bolt-on installation with no tuning required
• Replaces GM Part Numbers: 84841229, 84841225, 84262962, 85614333, 84554702
• MPN: WCF100684-CT
• Made in the USA

Fits 2011-2016 Chevrolet Silverado and GMC Sierra 2500/3500 HD models equipped with the 6.6L LML Duramax engine.

The WCFab 3.5-inch High Flow Passenger Side Intercooler Pipe replaces the restrictive factory two-piece plastic assembly with a single-piece, mandrel-bent 14-gauge aluminum pipe. This upgrade is designed to eliminate common failure points, such as blown factory boots and boost leaks, which frequently occur in high-performance or heavy-duty towing applications. By increasing the pipe diameter and smoothing the air path, this component provides a 23% gain in airflow over the stock configuration, resulting in improved throttle response and faster turbo spool-up.

This kit replaces the OEM clip ring design with heavy-duty silicone boots and stainless steel T-bolt clamps for a superior seal under high boost pressures. It includes a CNC-machined threaded bung to reinstall the factory Intake Air Temperature (IAT) sensor. This is a direct bolt-on part that requires no additional tuning or modifications.

• 3.5-inch diameter 14g aluminum construction
• 23% increase in airflow over factory pipe
• Durable powder-coated finish in WCFab Grey
• Includes high-temperature silicone boots and stainless T-bolt clamps
• Compatible with OEM Y-bridge and crossover pipe
• Made in the USA
• Manufacturer Part Number: WCF100682-GRY
• Replaces GM Part Numbers: 22737494, 20930188, 23421455, 84094727

Fits select 2011-2016 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 HD (6.6L LML Duramax).

Upgrade your LML’s charging system with the Wehrli Custom Fab 3.5 inch High Flow Passenger Side Intercooler Pipe. This one-piece cold-side pipe replaces the restrictive factory two-piece plastic unit and failure-prone OEM clip-ring design. By switching to a 14-gauge aluminum construction with high-quality silicone boots and stainless steel T-bolt clamps, this kit eliminates boost leaks and prevents blown-out boots common in high-performance or hard-working applications.

The larger diameter and smoother bends provide a 23% gain in airflow over stock, resulting in improved throttle response and faster turbo spool-up. This bolt-on component requires no tuning or additional modifications and includes an integrated threaded bung to reinstall your factory Intake Temperature Sensor.

• Increased Performance: 23% gain in airflow over the factory intercooler pipe.
• Durable Construction: Fabricated from 14-gauge aluminum with a gloss black powder coat finish.
• Improved Reliability: Replaces weak factory clip rings with heavy-duty silicone boots and T-bolt clamps.
• Direct Fit: Compatible with OEM Y-bridge/crossover pipe; no tuning required.
• Complete Kit: Includes all necessary boots and hardware for installation.
• MPN: WCF100682-GB
• Replaces OE Part Numbers: 22737494, 20930188, 23421455, 84094727
• Made in the USA.

Fits 2003-2009 Dodge Ram 2500 and 3500 (5.9L / 6.7L Cummins).

Upgrade your cooling system and eliminate the potential for failure associated with aging factory rubber hoses. This Wehrli Custom Fabrication (WCF) upper coolant pipe is constructed from durable aluminum and features a high-quality Bengal Red powder coat finish. It is designed to be a direct replacement for the OEM upper coolant hose, providing a more robust and visually appealing solution under the hood. This kit includes heavy-duty silicone boots and stainless steel T-bolt clamps to ensure a leak-free seal under pressure.

• Replaces failure-prone OEM rubber upper coolant hose
• Durable aluminum construction with Bengal Red powder coat finish
• Includes high-temperature silicone boots and T-bolt clamps
• Designed for use with OEM Ram radiators only (aftermarket radiators may cause fitment issues)
• NOT compatible with trucks equipped with twin CP3 pumps
• Manufacturer Part Number: WCF100678-BR
• Replaces MOPAR Part Numbers: 52028872AG, 52028872AC, 52028872AD, 52028872AE, 52028872AF, 55056665AA

The Wehrli Custom Fabrication (WCFab) WCF100674 extended turbo oil drain kit simplifies plumbing for midframe turbochargers by providing better wrench clearance. By extending the -10AN male fitting 4 inches away from the flange, this kit allows for easier installation and maintenance of the oil drain line without interference from the turbo housing.

CNC machined in the USA from billet aluminum, the adapter flange features a black anodized finish for corrosion resistance. It utilizes a reusable O-ring seal to eliminate the common leaks associated with traditional paper gaskets. This kit is designed specifically for T3, T4, and T6 midframe turbochargers that use a standard 2-inch on-center bolt spacing.

• Extends -10AN male fitting 4" from the turbo drain flange
• Includes reusable O-ring seal to replace leak-prone paper gaskets
• Fits T3, T4, and T6 midframe turbochargers (2" on-center bolt spacing)
• Precision CNC-machined billet aluminum construction
• Durable black anodized finish
• Made in the USA
• Manufacturer Part Number: WCF100674

Fits select 2001-2004 Chevrolet Silverado and GMC Sierra 2500 HD / 3500 (6.6L LB7 Duramax).

Replace the leak-prone, 16-gauge factory passenger side up pipe in your LB7 Duramax with this heavy-duty 2-inch stainless steel upgrade from WCFab. Designed specifically for single turbo applications where the turbo is mounted in the factory valley location, this up pipe features a significantly thicker 11-gauge wall construction and an upgraded HD stainless bellow. Unlike the thin OEM bellows that are prone to cracking and exhaust leaks, the WCFab design provides long-term durability and handles the high heat and pressure of performance diesel applications.

The larger 2-inch diameter improves exhaust flow compared to the restrictive stock pipe, helping to decrease Exhaust Gas Temperatures (EGTs) and improve turbo spool-up response. This up pipe is engineered to clear conventional downpipes behind the engine and is fully TIG welded for maximum strength and precision fitment.

• Manufacturer Part Number: WCF100654
• Replaces GM Part Number: 97302261
• Material: 11-Gauge Stainless Steel
• Finish: Raw Stainless
• Bellow Type: Heavy Duty Stainless Bellows
• Design: Fully TIG Welded
• Fitment Note: Compatible with OEM exhaust manifolds or WCFab Billet Exhaust Manifolds (WCF100363) only
• Included: (1) Passenger Side Up Pipe, (2) Up Pipe Gaskets