About this product
The WCFab WCF100414 Stage 2 High Flow Intake Bundle Kit upgrades both sides of the turbo on 2020-2026 L5P 6.6L Duramax Silverado and Sierra 2500HD and 3500HD trucks. It combines WCFab's Stage 1 High Flow Bundle and Stage 2 Intake Kit in one package: a 4" intake with an aluminum air box ahead of the turbo, and 3" and 3.5" intercooler pipes after it. No tuning required.
Fitment
Listed for 2020-2026 Chevrolet Silverado 2500HD and 3500HD and GMC Sierra 2500HD and 3500HD with the L5P 6.6L Duramax, single or dual rear wheel. WCFab wrote its description for the 2020-2025 L5P Silverado and Sierra 2500 / 3500, so verify fitment by VIN, and call us before ordering for a 2026. More L5P parts are in our Duramax section.
It does not fit 2017-2019 L5P trucks. GM changed the air box and panel filter with the 2020 truck, and 2017-2019 intakes do not interchange with 2020-2023 trucks. Intake makers also split L5P model years in different places, so go by this part's own year range rather than another brand's listing. It is not a Silverado or Sierra 1500 part either; the 1500 diesel is the 3.0L Duramax, a different engine.
The kit retains the factory connection points and sensors and fits a stock truck with no other modifications or upgrades.
Why this part
When an L5P feels lazy, check the air path before the turbo. Intake restriction makes turbo-control complaints worse, and a turbo that does not match its boost command often turns out to be an intake restriction or boost leak problem. Charge-air leaks at the intercooler boots and clamps show up as lost power under load that gets worse in the heat, while the truck feels normal on cool mornings. Boost runs below target, EGT climbs, and you may see underboost codes.
The factory setup gives both problems a place to start. Ahead of the turbo, restrictive plastic factory intake parts limit airflow. After it, boost travels through a restricted 2-piece 2.5 in. diameter driver (hot) side intercooler pipe and a leak-prone 2-piece plastic / rubber passenger (cold) side pipe that joins the Y-bridge with an OEM clip ring. WCFab calls these weak points that can contribute to lost power, boost leaks and complete failures in hard-working and high-performance trucks. Stage 2 replaces all of them to give the turbo and engine more airflow for better efficiency, throttle response and turbo spool-up.
On the intake side, WCFab's fabricated intake pipe, intake horn and air box enclosure with dry filter assembly replace the plastic factory parts and draw cold air through the hood Ram Air duct and inner fender. The pipe is all aluminum 14 ga. construction with large diameter 4 in. piping and smooth aerodynamic bends, which improves intake air velocity and volume. The intake horn is over an inch larger than the OEM diameter, and the air box is built from 10G aluminum sheet. WCFab says the intake significantly increases airflow to the turbo, producing improved horsepower and torque, cooler intake temperatures, and a more aggressive engine and turbo sound during acceleration.
On the boost side, the kit swaps in WCFab's heavy duty 3 in. diameter one-piece driver (hot) side and 3.5 in. diameter passenger (cold) side L5P intercooler pipes. Both are made in the USA from high strength 14 ga. aluminum tube with smooth mandrel bends for durability and flow. The 3 in. driver side pipe eliminates the OEM middle boot joint and uses reinforced silicone boots and stainless t-bolt clamps for better temperature resistance and boost holding. The 3.5" passenger side pipe has a CNC machined flange with a double o-ring seal and an upgraded silicone boot, so it withstands higher boost pressures than the factory components and ends blown factory boots and horsepower-robbing boost leaks.
What you get
- 4 in. Aluminum Intake Pipe
- 4 in. Intake Horn with PCV Port and Surge Ring
- Air box enclosure with dry filter assembly and Outerwears pre-filter cover
- Installation hardware, 4 in. silicone hump boot and stainless t-bolt clamps
- 3 in. Hot Side Intercooler Pipe
- 3.5 in. Cold Side Intercooler Pipe
- CNC Machined Flange and black anodized billet aluminum adapter with Double O-Rings provides an improved sealing surface to eliminate boost leaks
- OEM Clip Ring Design at Y-bridge connection replaced by high quality silicone boot and stainless steel t-bolt clamps for improved sealing and ability to hold higher boost pressures without leaking
- Silicone Boots
- Stainless Steel T-Bolt Clamps
- O-Rings
- Intercooler Outlet Clip
- Retains factory connection points and sensors
- NO Tuning required, bolt on.
- Will fit on stock truck no other modifications or upgrades necessary.
- Durable Powder Coat Finish
Specifications
- Part number: WCF100414 (Stage 1 High Flow Bundle plus Stage 2 Intake Kit)
- Intake pipe: 4 in. aluminum, 14 ga.
- Intake horn: 4 in. with PCV port and surge ring, over an inch larger than the OEM diameter
- Air box: 10G aluminum sheet with removable lid element, dry filter and hydrophobic Outerwears pre-filter cover
- Hot side intercooler pipe: 3 in., one piece, replaces the 2-piece 2.5 in. factory pipe
- Cold side intercooler pipe: 3.5 in., CNC machined flange, double O-rings, black anodized billet aluminum adapter
- Pipe construction: 14 ga. aluminum tube, mandrel bent, made in the USA
- Finish: powder coat, 25 color options (WCF100414-BB through WCF100414-SGS)
- Tuning: none required
Installation notes
Stage 2 installs with basic hand tools and bolts on to a stock truck with no tuning. It keeps the factory connection points and sensors. The kit comes with installation hardware, a 4 in. silicone hump boot, seals and stainless t-bolt clamps. Once it is in, the removable air box lid element makes it easy to look at and service the WCFab filter, and the included hydrophobic pre-filter cover helps keep the MAF sensor, turbo and engine airways free of contaminants.
About Wehrli Custom Fabrication
Wehrli Custom Fabrication (WCFab) is a DeKalb, Illinois fabrication company that started in 2010. Its High Flow intake bundle kits come in Stage 1, 2 and 3 versions for Duramax and Cummins, and most of its intake and intercooler parts are built for the 6.6L Duramax.
Frequently asked questions
Do I need a tune for the Stage 2 kit?
No. It is a bolt-on that fits a stock truck with no tuning and no other modifications. If you plan to go further, WCFab says it pairs best with emissions compliant tuning and upgraded drop-in turbochargers. On 2020-2023 trucks, drop-in 64/67 or 67/67 turbos fit without fabrication. The 2024 turbo is different, so a 2024 or newer truck needs a turbo listed for its year.
Will it fit my 2019 L5P?
No. The air box and filter changed with the 2020 truck, and 2017-2019 intakes do not interchange with 2020-2023 trucks. This kit is listed for 2020-2026 only.
My intercooler pipes are not leaking. Why replace them?
A charge-air leak is easy to miss. It shows up as a truck that feels soft under load in hot weather but normal on a cool morning. This kit also replaces the factory clip ring at the Y-bridge connection with a silicone boot and stainless t-bolt clamps, which seal better and hold higher boost without leaking.
Questions on fitment? Call the shop at the number in the header. We install everything we sell.
Description supplied by Southern Diesel Supply through its current Shopify listing. Product, performance, and health claims are the seller’s and have not been independently verified by StorkScout.
