Wehrli 100684 Stage 2 4 inch Intake Kit with Air Box | 2020-2025 GM Silverado/Sierra 2500HD/3500HD 6.6L Duramax L5P

Features:

• High-flow 4" aluminum intake pipe
• Includes oversized 4" intake horn
• Improves horsepower and torque
• Cooler intake temps for better efficiency
• Smoother bends increase air velocity
• Draws air from hood and fender
• Replaces restrictive factory components
• Custom powder coat color options
• Dry filter with pre-filter cover included
• No tuning required, bolt-on install
• Fits stock trucks, no mods needed
• Made in the USA

Stage 2 Intake System Improves Horsepower and Torque

If you're ready to give your L5P Duramax the breathing room it’s been missing, the Wehrli Stage 2 4in Intake Kit with Air Box brings a serious step up over the factory setup. This isn’t your average intake swap—it’s a purpose-built system that’s designed to get the most out of your turbo by improving airflow from the filter all the way to the compressor inlet. Whether you're towing, daily driving, or dialing in performance upgrades, this system helps unlock real, noticeable gains. What really sets the Stage 2 kit apart is the upgraded intake horn. Wehrli didn’t just match the OEM size—they went over an inch larger in diameter to eliminate the restriction right before the turbo. That factory bottleneck limits how much air your turbo can pull in, especially under load. By opening up that final section, the Stage 2 system creates a smoother, more direct path that helps the turbo spool faster and breathe deeper. Throttle response improves, temps drop, and the engine sounds noticeably more alive when you get into it.

Premium Intake Tube and Air Box with Direct-Fit Install

The intake pipe itself is a full 4 inches in diameter, constructed from high-quality aluminum and formed with smooth, flowing bends that maintain air velocity. The custom-fabricated air box is built from 10-gauge aluminum and sealed to pull in cool, dense air from both the hood’s Ram Air duct and the inner fender. That cold air makes a difference—especially when you're pushing the truck hard or working in hot conditions. Lower intake temps also help support better combustion and reduce heat soak, which matters for both performance and long-term reliability. Better yet, this kit comes with a dry filter and an Outerwears pre-filter cover to keep debris out without choking off airflow. Every piece—from the silicone boots to the stainless T-bolt clamps—is designed to hold up under the demands of daily driving, towing, or weekend performance use. And as you'd expect from Wehrli, the entire system is available in their signature powder coat colors, so it doesn’t just work well—it looks sharp under the hood, too.

Fits: 2020, 2021, 2022, 2023, 2024, 2025 GM 2500/3500HD 6.6L Duramax

Application Note: FAILURE TO DISABLE AIR FILTER MONITOR SYSTEM WILL RESULT IN A SERVICE AIR FILTER MESSAGE AND REQUIRE DEALERSHIP TO RESET THE SYSTEM. THE AIR FILTER LIFE WILL SHOW DISABLED MESSAGE WHEN SETTINGS ARE CORRECT.

Replaces the following GM Part Numbers: 84841229, 84841225, 84262962, 85614333, 84554702