S3 with revo intake popping :s

[R222cet]

So has this annoying little popping noise coming from the engine bay. tbh I though it was a leak on the down pipe or something but just been investigating and it’s coming from my revo intake. When the revs drop back to idle it pops, I’m sure it’s not always done this.
Is this normal or is something wrong ?
Tia

 

[smurfworth]

Normal, it's the recirculating valve opening and closing

 

[R222cet]

Ah I see thanks bud