16v Airfilter Box

[vwgti14]

hi,

Ive got at the moment the pipercross foam filter, which the last owner cut a large hole in the filter ...to improve air flow :O, ive got the standard filter box which i want to now fit, with an ITG or K & N filter element, looking into the box, how does the cold / hot air flap work ??
What makes it open / close, not sure if the box is missing some bits. Cheers

[rubjonny]

there should be a vacuum pipe connection to it, how it works depends on the age of the box. the older thin boxes have a funky spring inside with a sensor on, which controls the movem,ent of the flap, the later ones have a air sensor in the rubber elbow which does the same job