Cold Air Intake & Airflow Upgrades for Diesel Trucks
How to install a cold air intake, high-flow air filter, and intake horn on diesel trucks for more airflow, better throttle response, and increased turbo spool. Covers 6.7 Cummins, Duramax, and Power Stroke.
Tools Needed
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Instructions
Choose Your Intake Type
Drop-in replacement filter: swaps the OEM paper filter for a high-flow cotton gauze filter (K&N, S&B, AFE). 15–25 minutes to install. Short ram intake: replaces the airbox and intake pipe with a cone filter closer to the turbo — easier install but draws warmer under-hood air. Cold air intake (CAI): routes a cone filter outside the engine bay (into the fender, behind the bumper) for truly cooler, denser intake air. Diesel CAI kits from S&B, AFE, or Banks are the gold standard for diesel trucks.
Remove the Stock Airbox
Loosen the hose clamp connecting the intake tube to the turbo. Unplug the IAT (intake air temperature) sensor wire. Remove the airbox bolts/clips. Lift out the airbox and intake tube as an assembly. Note the routing of the intake tube — you'll replicate this with the new kit.
Install the New Intake Tube
Route the new intake tube following the kit instructions — most kits are designed to be direct-fit with no drilling required. Connect to the turbo inlet with the supplied coupler and T-bolt clamp. Torque the clamp to spec — too loose causes boost leaks, too tight can crack plastic couplers. Transfer the IAT sensor from the stock airbox to the new tube's bung (threaded port).
Install the Air Filter
Thread the cone filter onto the intake tube end. Tighten the filter clamp snugly — it must not be able to pull off under vacuum. Make sure the filter is positioned away from direct engine heat sources. If the filter is in the fender area, ensure it cannot contact the wheel or tire at full lock.
Check All Connections & Start
Double-check every clamp before starting. Start the truck and listen for air leaks (hissing from the intake tract). The intake will sound louder — you'll hear the turbo spool more prominently. This is normal and actually great feedback on turbo performance. No CEL should appear; if one does, check the IAT sensor connection first.
Filter Maintenance
High-flow cotton gauze filters must be cleaned and re-oiled every 25,000–50,000 miles (more often in dusty environments). Use the manufacturer's cleaning kit (Recharger kit for K&N). Never run an over-oiled filter — excess oil can foul the MAF sensor. Always let the filter dry completely before reinstalling after oiling.
