Dinan 19-26 BMW Z4 M40i Cold Air Intake

To achieve the gains in flow that the Dinan intake delivers, the entire lower box of the system, and not just the lid, has been reworked and enlarged in an effort to make use of as much of the available real estate as possible within the engine bay. In turn, this allows a 40% larger, custom, free flowing filter to be housed within and maximum flow to be realized. However, a secondary inlet has always been desired by Dinan to effectively fill the volume of the enlarged air box and increased filter surface area. This desire led to a multitude of experiments being conducted on the effectiveness of a possible open-air inlet in the system. With different shapes, locations, and sizes of openings being tested, the goal was to ensure that the added secondary inlet did not cause any unwarranted side effects such as an increase in air temps in the system. This is commonplace with open-air intake systems where overheated engine bay air is employed in the intake tract. The results of these tests showed that the patterned openings present in the final iteration of the box located on the opposite side from the engine provided a perfect balance of additional volume to assist the factory inlet all the while not causing an increase in turbo inlet temperatures. This was the case regardless of testing conditions (single/multiple gear pulls, constant speed, 0-100mph runs, etc.).