Please tell me what this hose is for?

Turbo wastegate.

But that isn't original, someone's already been there.

6 minutes ago, TomsFocus said:

Turbo wastegate.

But that isn't original, someone's already been there.

Looking at other. 1.0 ecoboom engines that "filter thingy" does not seem stock.

Is it some kind of filter?

And why would anyone install such thing..?

57 minutes ago, WinWiz said:

Looking at other. 1.0 ecoboom engines that "filter thingy" does not seem stock.

Is it some kind of filter?

And why would anyone install such thing..?

It's a one way valve.

Probably fitted because the original one-way valve on the vac pump is broken. (Black plastic part at the other end of the pipe).

Ford don't sell the valves separately. And the pumps cost around £500 last I checked. You can buy cheap replacement one-way valves on eBay but quality control is poor. Some break almost immediately.

I replaced the cracked hose with a similar hose from my motorcycle. But the lower connection with that yellowish/white plastic nozzle was very loose. So I secured it with a cable tie.

I'm pretty sure the connection is airtight but what will happen if it's not 100% ?

1 hour ago, WinWiz said:

I replaced the cracked hose with a similar hose from my motorcycle. But the lower connection with that yellowish/white plastic nozzle was very loose. So I secured it with a cable tie.

I'm pretty sure the connection is airtight but what will happen if it's not 100% ?

It's under vacuum so should all suck together with the engine running.

If that pipe isn't air-tight then you'll either get low boost or no boost at all, depending on how big the leak is.