Dinan Cold Air Intake - 2020-2024 BMW M340i/M440i Dinan Cold Air Intake

To achieve the gains in flow that set the Dinan intake system apart, the entire lower box of the system, and not just the lid, has been reworked and enlarged 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 in order 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.). With more air being pulled into the system, throttle response is improved and additional power is realized in the form of max gains of +9 WHP / +8 ft-lbs of torque. The secondary air inlets also allow the intake system to be more audible so the turbo spool and BOV can be appreciated. A stark difference from Dinan's traditional fully sealed systems where induction noise is not nearly as recognizable. While power and sound are the stars, the modest PEX construction fuses effortlessly into the factory engine bay for a reserved visual that despite basic materials still manages to draw attention. It's an economical solution to form and function for a vehicle that permeates both.