Wehrli WCF100718-GB Stage 1 High Flow Intercooler Bundle 2017-2019 Duramax L5P

Vehicle Fitment

• 2017-2019 Chevrolet Silverado 2500HD (6.6L L5P Duramax, 4WD/2WD)
• 2017-2019 Chevrolet Silverado 3500HD (6.6L L5P Duramax, 4WD/2WD)
• 2017-2019 GMC Sierra 2500HD (6.6L L5P Duramax, 4WD/2WD)
• 2017-2019 GMC Sierra 3500HD (6.6L L5P Duramax, 4WD/2WD)

Fitment Notes

• Designed specifically for the 2017-2019 L5P Duramax engine platform only - not compatible with LML, LGH, or 2020+ L5P applications.
• Retains all factory connection points and OEM sensors - no additional adapters required.
• Compatible with stock trucks - no tuning required for installation or operation.
• Cannot ship to the state of California.

Features

• Replaces the OEM 2.5" restricted, resonator-equipped 2-piece hot side pipe with a 3" 1-piece aluminum pipe, eliminating the resonator and middle boot joint for improved flow and reliability.
• Replaces the factory leak-prone 2-piece plastic/rubber cold side pipe with a heavy-duty 3.5" 1-piece aluminum pipe for superior boost pressure retention.
• CNC machined flange on the passenger (cold) side pipe features a double O-ring seal, providing a precision sealing surface that eliminates boost leaks at the intercooler connection.
• OEM clip ring design at the Y-bridge connection replaced with a high-quality silicone boot and stainless steel T-bolt clamps for improved sealing and higher boost pressure capability.
• Constructed from heavy-duty 14-gauge aluminum tubing with smooth, aerodynamic mandrel bends for maximum durability and optimized airflow.
• Reinforced silicone boots and stainless steel T-bolt clamps provide superior temperature and pressure resistance over OEM rubber and plastic components.
• SEMA Certified Emissions Compliant (Certification No. SC-WCF01-0176) - legal for use in all 49 non-California states.
• Finished in Wehrli's durable powder coat in Gloss Black - made in the USA at WCFab's Sandwich, Illinois facility.

Specifications

• Part Number: WCF100718-GB
• Finish / Color: Gloss Black powder coat
• Hot Side (Driver) Pipe Diameter: 3.0 inches (1-piece)
• Cold Side (Passenger) Pipe Diameter: 3.5 inches (1-piece)
• Tube Material: Heavy-duty 14-gauge aluminum
• Bends: Smooth, aerodynamic mandrel bends
• Flange Type: CNC machined with double O-ring seal (cold side)
• Clamp Type: Stainless steel T-bolt clamps
• Boot Material: Reinforced silicone
• Tuning Required: No
• Emissions: SEMA Certified Compliant - Cert No. SC-WCF01-0176
• Country of Manufacture: United States
• Package Weight: 12 lbs.

Included Components

• 1x 3" Hot Side (Driver) Intercooler Pipe - 1-piece aluminum, Gloss Black
• 1x 3.5" Cold Side (Passenger) Intercooler Pipe - 1-piece aluminum with CNC machined flange, Gloss Black
• 2x Reinforced silicone boots
• 2x Stainless steel T-bolt clamps
• 1x Set of double O-rings (cold side flange)
• 1x Intercooler outlet clip

Product Description

The Wehrli Custom Fabrication WCF100718-GB Stage 1 High Flow Intercooler Bundle Kit is a direct-replacement intercooler pipe upgrade engineered specifically for the 2017-2019 GM 6.6L L5P Duramax. The OEM intercooler pipe system is a known weak point on the L5P platform - the factory hot side pipe is a restricted 2-piece design with an integrated resonator, and the cold side relies on plastic and rubber components prone to splitting and leaking under elevated boost pressures. This kit resolves both failure points in a single installation. The 3" 1-piece aluminum hot side pipe eliminates the resonator and the middle boot joint, significantly reducing restriction and removing two common leak points in one part. The 3.5" 1-piece cold side pipe replaces the factory plastic and rubber assembly with a CNC machined flange featuring a double O-ring seal for a precision boost-tight connection at the intercooler.

Both pipes are constructed from heavy-duty 14-gauge aluminum tubing shaped with smooth mandrel bends for optimized airflow and long-term durability. The Y-bridge connection, which uses an OEM clip ring design prone to blowing off under heavy load, is upgraded to a reinforced silicone boot secured by a stainless steel T-bolt clamp - a substantially more reliable sealing arrangement for hard-working and high-performance applications. All factory connection points and sensors are retained, so installation requires no additional fabrication, no tuning, and no other modifications. The kit bolts directly onto a stock truck using basic hand tools.

Finished in a durable Gloss Black powder coat, this kit is made entirely in the USA at WCFab's Sandwich, Illinois facility. It carries SEMA Certified Emissions Compliance (Cert No. SC-WCF01-0176) and is legal for use in all 49 non-California states. The Stage 1 bundle saves over purchasing the hot and cold side pipes individually, making it the most cost-effective entry point into WCFab's L5P intercooler pipe lineup. Whether the goal is eliminating boost leaks on a stock daily driver or building a foundation for future power upgrades, the WCF100718-GB delivers a measurable improvement in airflow efficiency, throttle response, and turbo spool-up from the moment it is installed.