Wehrli 2017-2019 L5P Duramax Stage 3 High Flow Intake Bundle Kit
Can I pick up my order or have it installed at your shop?
Can I pick up my order or have it installed at your shop?
Absolutely. We offer local pickup on most products and full professional installation at our shop in Washington, MO. Whether you just want to grab your parts or have our techs handle the install, we’ve got you covered. Give us a quick call at 636-429-7020 or message us to schedule a visit — we’ll make sure the parts are ready when you arrive.
How do I know if this part fits my vehicle?
How do I know if this part fits my vehicle?
Unsure if it’ll fit? No problem — that’s what we’re here for. Send us your vehicle’s year, make, and model, and we’ll verify fitment before you order. We can also point you toward compatible upgrades or supporting parts if needed.
What if I need to return a product or it’s defective?
What if I need to return a product or it’s defective?
Most unused items can be returned within 30 days in their original packaging. Some products are covered by a manufacturer’s warranty as well. If something arrives damaged or doesn’t meet your expectations, just let us know — we’ll help you get it replaced, refunded, or repaired. (Tracking updates are also emailed automatically once your order ships.)
What's the lead time on custom or fabricated parts?
What's the lead time on custom or fabricated parts?
Many of our parts are built to order — especially fabricated or performance components. These can take additional time to produce before shipping. Lead times vary by manufacturer and demand, but we’ll always keep you updated along the way. If you’re working on a tight schedule, reach out before ordering at 636-429-7020 and we’ll confirm current availability or estimated ship dates.
Open up the entire airflow path on your 2017-2019 Chevrolet Silverado / GMC Sierra 2500HD/3500HD 6.6L Duramax L5P with the Wehrli Stage 3 High Flow Intake Bundle Kit (Manufacturer Part # WCF100403). This is Wehrli's Stage 2 High Flow Bundle combined with their 3.5" down pipe — intake, air box, both intercooler pipes and the exhaust down pipe in one package, replacing every restrictive plastic and crushed-tube section between the hood duct and the factory front pipe. Bolts to a stock truck, no tuning required.
Why Choose the Wehrli Stage 3 High Flow Intake Bundle Kit?
- 4" fabricated intake path – 14 gauge aluminum pipe and horn with smooth mandrel bends replace the restrictive factory plastic, and the horn runs over an inch larger in diameter than the OEM piece.
- Cold air where it counts – the sealed 10 gauge aluminum air box pulls from the hood ram air duct and inner fender, and the critical duct seal moves to the underside of the hood for a cleaner engine bay.
- Resonator delete on the hot side – the 3" one-piece driver side pipe eliminates the OEM resonator and the middle boot joint, killing two restrictions and two failure points at once.
- No more blown factory boots – the 3.5" passenger side pipe uses a CNC machined flange with a double O-ring seal in place of the OEM clip ring design, where boost leaks on this platform usually start.
- Ceramic coated down pipe – the 3.5" DOC-back pipe replaces the crushed factory section, arrives heat wrapped, and includes bungs for the factory sensors.
- Hardware that holds boost – reinforced silicone boots and stainless steel T-bolt clamps throughout instead of clip rings and rubber.
- Serviceable filter – the removable air box lid element lets you inspect the filter and its hydrophobic pre-filter cover without pulling the box apart.
Kit Includes
- 4" aluminum intake pipe
- 4" intake horn with PCV port and Surge Ring
- Air box enclosure with dry filter assembly and Outerwears pre-filter cover
- 3" driver (hot) side intercooler pipe
- 3.5" passenger (cold) side intercooler pipe
- 3.5" DOC-back down pipe, black ceramic coated with heat wrap pre-installed
- Installation hardware, 4" silicone hump boot and stainless T-bolt clamps
- Silicone boots, stainless steel T-bolt clamps, O-rings and intercooler outlet clip
Installation Highlights
Installs with basic hand tools — no drilling, no fabrication, and nothing cut off the factory exhaust. The kit retains every factory connection point and sensor location, and the down pipe mates to the OEM exhaust front pipe at the four bolt style flange. Will fit a completely stock truck with no other modifications or upgrades necessary.
Fits These Models
2017, 2018 and 2019 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD with the 6.6L Duramax L5P.
Specifications
- Intake pipe: 4" diameter, 14 gauge aluminum
- Air box: 10 gauge aluminum sheet
- Driver (hot) side intercooler pipe: 3" diameter, 14 gauge aluminum, one piece
- Passenger (cold) side intercooler pipe: 3.5" diameter, 14 gauge aluminum
- Down pipe: 3.5" diameter, DOC back
- Shipping weight: 65.0 lbs
- Package dimensions: 36" W x 24" H x 12" L, ships in its own box
- Finish: custom powder coat, color selected above
- Made in the USA
Key Features at a Glance
- Complete Stage 2 bundle plus down pipe - intake and exhaust side handled in one order.
- 4" intake, 3" hot side, 3.5" cold side - every factory restriction upsized.
- CNC machined double O-ring flange - seals where the factory clip ring fails.
- Ceramic coated, heat wrapped down pipe - better thermal efficiency out of the box.
- No tuning required - bolt on to a stock truck.
- Custom powder coat finish - pick your color above.
Notes
- 2017-2019 only. The 2020 and newer L5P uses a different bundle — intake and charge pipe geometry changed. Confirm your model year before ordering.
- Emissions equipped trucks. The down pipe is a DOC-back piece that retains the factory emissions hardware and sensor locations.
- On the horsepower figure: Wehrli reports a 25 HP gain from the 4" turbo inlet, measured with a Max Effort tune. Treat that as a tuned result. On a stock truck this kit is an airflow and reliability upgrade.
- Lead time varies by color. WCFab Red and Gloss Black are stocked and ship in 3-5 business days. All other colors are made to order on a 10-15 business day lead time.
- Stage 3 bundles pair best with emissions compliant tuning and a larger drop-in turbocharger.
FASS SKU: [ADD FASS SKU]
Manufacturer Part #: WCF100403
Questions? We’re Here to Help.
Have questions about upgrades for your 6.6L Duramax L5P? Contact FASS Motorsports and we’ll get you dialed:
Phone: 636-429-7020
Email: info@fassmotorsports.com
This part fits the following vehicles:
| Years | Make & Model |
|---|---|
| 2017, 2019 | Chevrolet Silverado 2500 HD |
| 2017, 2019 | Chevrolet Silverado 3500 HD |
| 2017, 2019 | GMC Sierra 2500 HD |
| 2017, 2019 | GMC Sierra 3500 HD |
Fitment is listed by year, make and model. Some applications also depend on cab, bed, drivetrain or engine — if you are not sure, call 636-429-7020 or send us your vehicle details and we will confirm before you order.
