Does a turbo sometimes consume more air than normal?

[Derp]

It's a bit of a stupid title, but let me explain;

We have a LWB 2.5d Transit at work. It's a new one (60 Plate).

When driving along, you can sometimes hear the engine/turbo and it sounds like it's pulling in loads and loads of air. It's enough to make people look round, and it only work in 1st and 2nd. It works on the gearchange but only if you hold the revs above the 2k mark. The noise is enough to drown out the engine noise as such.

It sounds like a loud surging of air, but there's no performance difference, it just makes it sound like a right beast

Is this this turbo just taking in more air for some reason? I can manipulate it fairly well now, anb it does it about 60% of the time. The other 40% just sounds like a high revving diesel.

It's not faulty, as i've tried it on another 2 vans of the same year and mileage (less than 30k on the clock), and that does the same thing.

So PH knowledge fountain, what is it?

[v8will]

Sounds like some sort of recirculation valve or maybe (a guess) a variable vane turbo?

[The Wookie]

Sounds like a boost leak to me...

[dtrump]

Turbo noises

[playalistic]

The Wookie said:

Sounds like a boost leak to me...

This was my thinking too...

[paranoid airbag]

You should try standing next to a few marine diesels....

Do these have a blow-off valve? That could be stuck open, although you'd presumably notice a lot less power. Anyway, yes, there are a fair few ways a turbo could be leaking/consuming air.

[Derp]

How can it be a leak if 3 vans all do it, less than 2 years old with harldy any mileage and no loss in performance?