Boost Tube Upgrade Kit Red Powder Coated (Set) for 17-19 Chevy/GMC 2500/3500 6.6L Duramax L5P Banks PowerBanks massive 3. 5 inch boost tubes are the largest charge air cooler pipes on the market, flowing 680 CFM and 87 percent 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. Banks Boost Tubes are the largest charge air cooler pipes in the industry measuring in at a full 3. 5 inch. Every other competitive product on the market tops out at 3. 0