This LML Y-Bridge Kit is an upgraded high flow intake kit for the 2011-2016 6.6L Duramax diesel engine which replaces the OEM upper intake manifold supplying air to the engine intake runners and cylinder heads. The OEM Y-bridge for these trucks is a restrictive part that creates a bottle neck in the air intake tract and limits engine performance potential. This kit improves air flow by 36% using a precision CNC machined cast aluminum high flow bridge which provides maximum airflow volume for the available space. This means you get the most out of your engine in terms of performance and efficiency. Includes a unique, 20% larger than stock, 3" fabricated aluminum upper crossover intercooler pipe that allows you to take full advantage of the larger inlet diameter of this bridge. Incorporates factory intake air heater grid for superior cold weather performance. Billet resonator plate eliminates the stock plastic resonator for improved engine bay appearance and more aggressive turbo and engine sound. Compatible with OEM throttle valve, EGR controls, and lower passenger side Intercooler Pipe. Add WCFab 3.5" High Flow Intercooler Pipe WCF100682 to get the most out of this kit. Finished in your choice of custom powder colors. This product is compatible with stock trucks requiring no additional modifications, upgrades, or tuning for installation. Pairs best with emissions compliant tuning and drop in turbochargers for optimum performance gains. Supersedes WCF100607. Replaces the following GM part numbers: 12658233