Wehrli 2001-2004 LB7 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.
Get the restrictive factory plastic off your 2001-2004 Chevrolet Silverado / GMC Sierra 2500HD/3500HD 6.6L Duramax LB7 with the Wehrli 4" Stage 2 Intake Kit with Air Box (Manufacturer Part # WCF100300). Fabricated aluminum intake pipe, sealed air box with a dry filter, and a 4" high flow turbo intake horn — the whole inlet path from the fender to the turbo, in one kit. Installs with basic hand tools.
Why Choose the Wehrli 4" Stage 2 Intake Kit with Air Box?
- 4" pipe in 14 gauge aluminum – large diameter with smooth aerodynamic bends in place of the factory plastic, improving intake air velocity and volume.
- 4" high flow turbo intake horn included – removes the restriction in the OEM setup for better spool and top end power. Compatible with the OEM turbo and with upgraded drop-in IHI style turbochargers.
- Cold air from the inner fender – the sealed air box draws cooler air than the factory arrangement, which shows up as lower intake temperatures.
- 10 gauge aluminum box and lid – heavier construction than anything plastic, and the lid element lifts off for a filter check without tearing the box down.
- Dry filter with a hydrophobic pre-filter cover – the Outerwears cover keeps water and grit out, protecting the MAF sensor, turbo and engine airways.
- Sealed with an O-ring and T-bolt clamps – silicone boot, O-ring seal and stainless steel T-bolt clamps rather than the factory clips.
- More sound – a noticeably more aggressive engine and turbo note under acceleration.
Kit Includes
- 4" intake pipe, 14 gauge aluminum
- 4" high flow turbo intake horn
- Air box and lid, 10 gauge aluminum sheet
- Dry air filter
- Outerwears pre-filter cover
- Silicone boot, stainless steel T-bolt clamps and O-ring seal
- Installation hardware
Installation Highlights
Installs easily with basic hand tools. The high quality hardware, silicone boot and seals are there for durability as much as for ease of installation, and the removable air box lid keeps ongoing filter maintenance to a two-minute job.
Fits These Models
2001, 2002, 2003 and 2004 Chevrolet Silverado 2500HD/3500HD and GMC Sierra 2500HD/3500HD with the 6.6L Duramax LB7.
Specifications
- Intake pipe: 4" diameter, 14 gauge aluminum
- Turbo intake horn: 4" high flow, compatible with OEM and drop-in IHI style turbochargers
- Air box and lid: 10 gauge aluminum sheet
- Filter: dry element with Outerwears hydrophobic pre-filter cover
- Supersedes: WCF100636
- Replaces GM part numbers: 19201277, 25345138, 21993711, 15076901
- Shipping weight: 17.0 lbs
- Package dimensions: 16" W x 16" H x 24" L, ships in its own box
- Finish: custom powder coat, color selected above
- Made in the USA
Key Features at a Glance
- 4" pipe and 4" turbo horn - the whole inlet path upsized, not just the tube.
- 10 gauge aluminum air box - sealed, serviceable, no plastic.
- Dry filter with Outerwears cover - protects the MAF sensor and turbo.
- IHI drop-in turbo compatible - works with the OEM charger or an upgrade.
- Basic hand tools - no drilling, no fabrication.
- Custom powder coat finish - pick your color above.
Notes
- Lead time varies by color. WCFab Red, WCFab Grey, Gloss White 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.
- This part supersedes WCF100636. If you are cross-shopping an older listing under that number, this is the current version.
FASS SKU: [ADD FASS SKU]
Manufacturer Part #: WCF100300
Questions? We’re Here to Help.
Have questions about upgrades for your 6.6L Duramax LB7? 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 |
|---|---|
| 2001, 2004 | Chevrolet Silverado 2500 |
| 2001, 2004 | Chevrolet Silverado 3500 |
| 2001, 2004 | GMC Sierra 2500 |
| 2001, 2004 | GMC Sierra 3500 |
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.
