In the quest to be all things to all people at an attractive price point the 230i/330i/430i has been reduced to a mundane, albeit pragmatic, core with elements devoid of any character both outwardly and inwardly. For example, in stock trim, the 230i/330i/430i comes with a utilitarian and lifeless air box swaddled by seemingly unfinished braces and housing a basic panel filter that is also accompanied by an intake resonator whose job it is to eliminate turbo/intake noises. The same noises that those in the performance world relish. Essentially, BMW has seen fit to give 230i/330i/430i owners an air box that looks uninspiring, flows adequately but not ideally, and emits no noise. The Dinan carbon fiber intake for the platform rights these wrongs and delivers a semi-open intake capable of flowing 58% more air than the stock system resulting in improved throttle response and the elimination of a potential roadblock when opting to pursue a high-powered build (upgraded turbo, fueling, etc). At the same time the Dinan kit unveils a more aggressive, sporty carbon fiber appearance, and an increase in sound courtesy of the removal of the intake resonator and implementation of the semi-open design.
In order to accomplish the feat in flow that sets the Dinan intake system apart 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 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 on the opposite side from the engine provided a perfect balance of additional volume to assist the factory snorkel 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.).
While the additional flow does not translate to any noteworthy rise in power output for stock or basic bolt-on equipped vehicles, the Dinan intake system does expand the potential of the platforms power ceiling. Put simply, those striving to build a more potent and robust solution, complete with turbo and fueling upgrades, will be allowed to maximize the results without worry of the intake system being a limiting factor. Regardless of the level of build, the secondary air inlets 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. Not to be outdone by the increased flow and sound, the outwardly visible system is made of immaculate carbon fiber so the under the hood appeal is vastly improved over its drab and utilitarian beginnings. In and of itself, making it worth the price of admission.