Upgraded Intercooler Boost Tube &Turbo Horn Upgrade Kit 17-19 6.6L Duramax Diesel L5P Increases throttle response and reduces turbo lag!! Polished (Set) FOR 2017-2019 CHEVY/GMC 2500/3500 6.6L DURAMAX, L5P Our massive 3.5in boost tubes are the largest charge air cooler pipes on the market, flowing 680 CFM and 87% more air than stock! Smooth mandrel-bent tubes deliver more air to your engine while reducing boost pressure loss resulting in quicker turbo spool and more power. Specifications These Boost Tubes are the largest charge air cooler pipes in the industry measuring in at a full 3.5 inches. Every other competitive product on the market tops out at 3.0 inches, and your factory pipes are only 2.5 inches with crushed bent corners and flimsy plastic components. By contrast, our Boost Tubes are made of high-quality stainless steel for maximum strength and durability. With our Boost Tubes' smooth bends, your turbo can spool quicker thanks to improved boost pressure retention for maximum horsepower. 3.5" Turbo Intake Horn Gloss Black w/ PCV Port Fits 2017-2019 Duramax L5P 3 1/2" Turbo Intake Horn for the 2017-2019 L5P Duramax with factory style Turbo. The OEM plastic intake horn is 2.4" diameter and we experienced a 25HP Gain with our 3.5" Horn when used with a Max Effort Tune. Tuning not required, this horn will work plug and play tuners or OEM calibration. Fitment: 2017-2019 Chevrolet Silverado 2500HD/3500HD 6.6L L5P Duramax 2017-2019 GMC Sierra 2500HD/3500HD 6.6L L5P Duramax