I have an SLK sport and obviously have the sport air box. Had if for 9 months now.
Air is drawn in from the Front mainly but there is an opening at the rear of each side by the filters, that draws air in from inside the Engine compartment. It is about 20mm in diameter and is protected by a metal gauze.
The Membrane is again on both sides and is thick rubbery material but it is quite loose. I assume this flaps in and out with the varying air pressure in the box. Coming from an Audi TT this is a standard trick to mod the air box to make the air in the air box vortex a bit, sounds like gulping.
As a side note I have changed to Green Filters and they null out some of the noise. So the Mercedes Benz Engineers have tuned this box for Paper filters. |