engine whine at full throttle

Hi ALL

I've got a weird thing that happened to my d40 after coming off the canning stock route.
when i'm doing heavy acceleration ( so when the waste gate is fully open) it sounds like a really loud turbo whistle but stops as soon as you ease off.

i thought at first it may have been the turbo throwing in the towel but i had a look and wipe inside the the outlet pipe off the turbo and there is no metal fillings or anything so it's not the impeller rubbing.

i've checked the boost hoses they all seem in working order.
I'm still getting good power and full economy and the turbo is still whistling away nicely while driving normally.
also no oil stains/splatter in the engine bay so don't think anythings leaking

so if any one has any ideas please shear.

Could be the end tanks on the intercooler leaking, you may only hear it when on full boost. The noise you are describing sounds like a boost leak, so if you're sure the hoses are all in good condition, that would be the next thing to check.

Oh and d40s don't have a wastegate, the have a variable nozzle turbocharger (vnt), so boost is continuously variable, controlled by the ECU.

It's possibly the gasket between the turbocharger's turbine inlet and the exhaust manifold. Mine went - twice - the gasket acts like a reed in a clarinet and is capable of all sorts of squealing. At full noise, this area is also under max pressure.