Stage 3 upgrade for the 2017-2019 L5P Duramax combines our Stage 2 High Flow Bundle and 3.5 in. Down Pipe into a single package providing increased air and exhaust flow for your turbo and engine for improved efficiency, throttle response, and turbo spool up. Eliminates weak points in the factory design that can contribute to lost power, boost leaks, and complete failures in hard working and high performance applications.

On the air intake side, our high flow fabricated intake pipe, intake horn, and air box enclosure with dry filter assembly replaces the restrictive plastic factory parts on 2017-2019 L5P Duramax Diesel for improved engine performance and sound. Significantly increases airflow to your turbo producing improved horsepower and torque and cooler intake temperatures by drawing cold air through the hood Ram Air duct and inner fender. All aluminum 14 ga. construction features large diameter 4 in. piping with smooth aerodynamic bends. Improves intake air velocity, volume, and provides a more aggressive engine and turbo sound during acceleration. The intake horn is over an inch larger than the OEM diameter and we experienced a 25HP Gain with our 3.5 in. turbo inlet when used with a Max Effort Tune.

High quality hardware, silicone boot, seals, and stainless steel t-bolt clamps ensure optimum durability and ease of installation. Removable air box lid element allows for easy visual inspection and maintenance of your WCFab filter with included hydrophobic pre-filter cover, to help keep your MAF sensor, turbo, and engine airways contaminant free. The critical ram air duct seal has been moved to the bottom of the hood for a clean engine compartment appearance.

After the turbo, our Stage 3 kit also upgrades the restricted 2-piece, resonator equipped, 2.5 in. diameter driver (hot) side intercooler pipe and leak-prone 2-piece plastic / rubber passenger (cold) side pipe with WCFab's heavy duty 3 in. diameter 1-piece Driver (Hot) Side and 3.5 in. diameter Passenger (Cold) Side L5P Intercooler Pipes. Made in the USA from high strength, heavy duty 14 ga. aluminum tube with smooth, aerodynamic mandrel bends for increased durability and optimized flow.

3 in. Driver Side pipe eliminates the OEM resonator and middle boot joint for improved flow and durability and includes high quality reinforced silicone boots and stainless t-bolt clamps for superior temperature resistance and boost pressure holding capabilities.

3.5 in. Passenger Side pipe features a CNC machined flange with a double o-ring seal and an upgraded silicone boot in order to withstand higher boost pressures than the factory components to increase reliability and eliminate blown factory boots and horsepower robbing boost leaks.

Full assembly finished in your choice of WCFab's signature custom powder coat colors for a look as unique as your truck.

On the exhaust side our 3.5 in Down Pipe replace the restrictive crushed factory part for improved flow. Black Ceramic Coated and heat wrapped for improved thermal efficiency.

Connects to the DOC (Diesel Oxidation Catalyst) outlet flange and mates with OEM exhaust system front pipe with the 4 bolt style flange connection and includes bungs for OEM sensors.***

Compatible with stock trucks, no tuning required.

Stage 3 bundle kits pair best with emissions compliant tuning and drop in turbochargers for optimum performance gains.

Installs with basic hand tools. Saves $80 vs. buying individually.