Are you speaking of the Intake tube? If so, you'll need to cover it with a thermal or heat resistant sock or sleeve material. They can be purchased from several different companies;
https://www.heatshieldproducts.com/automotive/thermal-and-heat-shield-sleeving
https://designengineering.com/cool-cover-air-tube-cover-kit/
https://www.mishimoto.com/automotive/heat-protection.html?limit=all
https://www.thermotec.com/products/sleeving
Everyone has this problem to some extent. Products offered
above^ will solve a majority of the issue.
The other issue is;
heat soak. They have various products that will help specific areas of the engine which produce high temps. Once these are addressed, you'll have less of an issue. It will however, always be present to some extent, according to how high ambient temps are and how you are driving the car.
Keep in mind, it's not so much the heat on the intake tube but the higher IAT's. One of the best ways to address it, will be with a larger intercooler from;
Forge or Wagner, etc. This will drastically cool the air being circulated thru the turbo.
You can also add;
Phenolic Thermal Intake Manifold &
throttle body spacer. The throttle body spacers, are available now but not the intake manifold spacer. It should be available soon, from Boomba Racing.
Check out; @
TarmoT 364,5bhp i30ntracktoy. He's has been addressing these specific areas. He can verify what has worked for him, on his i30N.
Are you tuning or utilizing a tuner yet?