What is included in the Stage 2 bundle versus buying components separately?

The Stage 2 bundle includes the 4-inch air intake assembly, 3-inch Y-bridge kit, both intercooler pipes, the 4-inch turbo intake horn, FPRV block-off kit, all silicone boots and T-bolt clamps, MAP sensor seal, hold-down bracket, and O-ring gaskets. It combines the Stage 1 bundle and Stage 2 intake kit into one package.

Is tuning required after installing this kit?

The Stage 2 kit replaces the intake tract and Y-bridge but does not require a tune to function. However, the manufacturer notes it pairs well with emissions-compliant tuning for further performance gains.

Is the turbo intake horn compatible with upgraded turbochargers?

Yes. The included 4-inch high flow turbo intake horn is compatible with both OEM turbochargers and upgraded drop-in IHI-style turbochargers.

Is this legal for street use?

This kit is not CARB approved and may not be legal for street use in California and other CARB-regulated states. Verify your local emissions regulations before purchasing.

Specifications

Brand: Wehrli
Part #: WCF100435-CAT
UPC: WCF100435-CAT

Wehrli 01-04 Duramax LB7 Stage 2 High Flow Intake Bundle Kit - Cat Yellow

Name: Wehrli 01-04 Duramax LB7 Stage 2 High Flow Intake Bundle Kit - Cat Yellow
Brand: Wehrli
SKU: wehrli-wehrli-01-04-duramax-lb7-stage-2-high-flow-intake-bundle-kit-cat-yellow-t14-730194
Price: 1899.52 USD
Availability: BackOrder

$1899.52

On Backorder

Order now to reserve yours — we'll ship as soon as stock arrives. Full refund if we're unable to fulfill.

Fits 2001-2004 Chevy/GMC Duramax LB7. Wehrli Stage 2 high flow intake bundle kit in Cat Yellow with 4-inch intake and 3-inch Y-bridge.

Key Features

Verified fitment for 2001-2004 Chevrolet Silverado 2500 HD, 3500 and GMC Sierra 2500 HD, 3500 with LB7 Duramax
4-inch high flow air intake with dry filter, Outerwears pre-filter cover, and air box with removable lid
3-inch fabricated aluminum Y-bridge with TIG welded, CNC machined billet base
3-inch driver (hot) side and passenger (cold) side intercooler pipes
High flow 4-inch turbo intake horn compatible with OEM and IHI-style turbochargers
Silicone boots and stainless steel T-bolt clamps for boost leak resistance

⚠️ CA WARNING: This product can expose you to chemicals known to the State of California to cause cancer and/or birth defects or other reproductive harm. Learn more

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Will this fit your vehicle?

Advanced difficulty to install

Multi-component kit replacing the Y-bridge, both intercooler pipes, and factory air intake. Refer to the manufacturer's installation instructions.

About this part

Product Details

Swapping out the restrictive factory intake on a 2001-2004 Duramax LB7 is one of the first modifications most owners consider, and Wehrli Custom Fab's Stage 2 High Flow Intake Bundle Kit packages everything you need into one box. This Cat Yellow version (part number WCF100435-CAT) combines the Stage 1 high flow bundle with the Stage 2 intake kit, replacing the OEM Y-bridge, both intercooler pipes, and the factory plastic air intake with fabricated aluminum components.

Starting at the filter end, you get a 4-inch high flow air intake with a dry filter element, Outerwears hydrophobic pre-filter cover, and an air box enclosure with a removable lid for easy filter inspection. The kit includes a high flow 4-inch turbo intake horn that replaces the restrictive factory piece and is compatible with both OEM and upgraded drop-in IHI-style turbochargers. Moving downstream, the 3-inch mandrel-bent aluminum Y-bridge replaces the factory unit and feeds into the TIG welded, CNC machined billet Y-bridge base. Both the driver (hot) side and passenger (cold) side intercooler pipes are upgraded to 3-inch diameter, creating a full 3-inch intake tract between the turbo and engine.

All piping is 14 gauge aluminum construction, and the kit includes silicone boots with stainless steel T-bolt clamps rated for higher pressures and temperatures than the factory rubber parts. An FPRV (Fuel Pressure Regulator Valve) block-off kit is also included to provide clearance for the larger Y-bridge assembly, along with MAP sensor seal, hold-down bracket, and O-ring bridge flange gaskets. The whole assembly comes finished in Wehrli's Cat Yellow powder coat. Note that this kit is not CARB approved.