Wehrli 2011-2016 LML Duramax 4" Intake Kit with Air Box Stage 2
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.
Replace the restrictive plastic inlet on your 2011-2016 Chevrolet Silverado / GMC Sierra 2500HD/3500HD 6.6L Duramax LML with the Wehrli 4" Stage 2 Intake Kit with Air Box (Manufacturer Part # WCF100304). Fabricated 4" aluminum pipe, sealed 10 gauge air box with a dry filter, and a 4.8" cast aluminum turbo intake horn that deletes the factory resonators. Wehrli measures 37% more airflow than the stock intake. Bolt on, no tuning required.
Why Choose the Wehrli 4" Stage 2 Intake Kit with Air Box?
- 37% more airflow than stock – Wehrli's own figure for the intake, plus another 5.6% over the stock intake horn, from 4" piping with smooth aerodynamic bends instead of molded plastic corners.
- 4.8" cast aluminum turbo intake horn included – removes the OEM restriction and eliminates the factory resonators, which cleans up the engine bay and lets the turbo actually be heard. Compatible with the OEM charger and with drop-in VGT style upgrades.
- Cold air from the inner fender – the sealed box pulls cooler air than the factory setup, so intake temperatures drop.
- 10 gauge aluminum box and lid – and the lid element comes off for a filter inspection without dismantling anything.
- Dry filter with a hydrophobic pre-filter cover – the Outerwears cover keeps water and grit off the element, protecting the MAF sensor, turbo and engine airways.
- Silicone boots and stainless T-bolt clamps – sealed properly, and easier to install than the factory clip hardware.
- Custom powder coat – finished in your choice of Wehrli's colors. Made in the USA.
Kit Includes
- 4" intake pipe, 14 gauge aluminum
- 4.8" high flow cast aluminum turbo intake horn
- Air box and lid, 10 gauge aluminum sheet
- Dry air filter
- Outerwears pre-filter cover
- Silicone boot and stainless steel T-bolt clamps
- Installation hardware
Installation Highlights
Installs easily with basic hand tools and needs no tuning — it bolts onto an otherwise stock truck. The removable air box lid keeps ongoing filter service to a couple of minutes.
Fits These Models
2011, 2012, 2013, 2014, 2015 and 2016 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD with the 6.6L Duramax LML.
Specifications
- Intake pipe: 4" diameter, 14 gauge aluminum
- Turbo intake horn: 4.8" high flow cast aluminum, compatible with OEM and drop-in VGT style turbochargers
- Air box and lid: 10 gauge aluminum sheet
- Filter: dry element with Outerwears hydrophobic pre-filter cover
- Airflow: 37% improvement over the stock intake, 5.6% over the stock intake horn, per Wehrli
- Replaces GM part numbers: 23467660, 20917396, 15819728, 25881207, 20847795, 23210121, 22870902
- Shipping weight: 13.0 lbs
- Package dimensions: 36" W x 18" 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
- 37% airflow gain over stock - measured by Wehrli, not estimated.
- 4.8" cast turbo horn included - resonators deleted, VGT drop-in compatible.
- 10 gauge aluminum air box - sealed, serviceable, no plastic.
- Dry filter with Outerwears cover - protects the MAF sensor and turbo.
- No tuning required - bolt on to a stock truck.
- Custom powder coat finish - pick your color above.
Notes
- ⚠ 2011 model year trucks must update the PCV regulating valve to 2012-2016 model year spec for this part to fit and function correctly. If you have a 2011, sort the valve before you install.
- ⚠ Not compatible with aftermarket LML Y-bridges that relocate the manifold or bridge inlet away from the original factory driver side inlet position.
- The air box is not compatible with the intake pipe from kits WCF100337, WCF100689 or WCF100691.
- Lead time varies by color. WCFab Red, WCFab Grey, Candy Teal, Bengal Red, Gloss Black and Gloss White are stocked and ship in 3-5 business days. All other colors are made to order on a 10-15 business day lead time.
Installation Instructions Available Here
FASS SKU: [ADD FASS SKU]
Manufacturer Part #: WCF100304
Questions? We’re Here to Help.
Have questions about upgrades for your 6.6L Duramax LML? 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 |
|---|---|
| 2011, 2016 | Chevrolet Silverado 2500 HD |
| 2011, 2016 | Chevrolet Silverado 3500 HD |
| 2011, 2016 | GMC Sierra 2500 HD |
| 2011, 2016 | 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.
