When upgrading your intake its common to upgrade to a cold air intake so you get better flow and in return better performance. Most stock intakes are fairly restrictive and these cold air intakes alleviate that.
That’s what its like on most cars, but not necessarily the MK7 MQB platform. Our stock intakes actually flow very well it just need a high flow filter. Changing the stock filter panel out for an AFE/K&N or similar high flow panel filter will give you enough flow to match most aftermarket intakes and surely enough for our turbos. Unless you are running a very large turbo, a high flow filter on the stock intake and maybe snow guard removal is all you need.
OK, enough rambling now onto the problem. Our engine bays gets heat soaked very easily, more than most platforms. Due to this having an open air intake filter inside the engine bay is not getting cold air some of the time and is actually drawing in that engine bay heat. The stock intake is enclosed and uses ducts to gets air from outside the engine bay.
When moving at speed the engine bay gets air flow and helps with this issue. Just don’t stop for stop signs, be in traffic or idle a lights and you will be fine. I’m kidding please obey the rules of the road, but it gives you the idea that if the car is not moving fast enough to get proper airflow the engine is heating up and getting heat soaked. It takes a bit of driving for the engine bay to recover from heat soak, its not an instant thing once you start driving again.
Because of this I have started calling cold air intakes, hot air intakes. These intakes are popular because they are cheaper, allow more turbo noises and on other platforms work very well. But I highly suggest if you have to replace the stock intake that you get an enclosed one that draws air from outside the engine bay.