Car: 2006 2.0T (TFSI) s-line special edition with BUL engine (same as A4 DTM)

New turbo fitted recently (Chinese el cheapo)

Garage made a C**t of it, breaking both old and new N75 valves, amongst other examples of bad workmanship.

When I got the car back from the garage I thought maybe some mechanical tomfoolery (wastegate cranking or the like) had been reversed by fitting new turbo....or a remap had been reset. Not long purchased the car so no idea who to call about it.

So I called a local tuner in to remap the car.
No luck, car wouldn't respond.

Then I found they broke both my N75 solenoids.

Soooooo.....

Ordered a new Pierburg N75 solenoid and car started responding, spiking 15psi settling at 12psi.

Tuner came back out to put a more aggressive tune on......

Car still only spiking then settling at 12psi.

Have checked for boost leaks, none up to 20psi.


At a loss as to why that may be.
Since the first visit from the tuner I fitted new air filter, new plugs, new N75, new DV+, PCV delete, fixed oil leak from Vacuum pump, boost leak tested to 20psi.

By all means the car should be making more than 12psi (figure unknown at this point but probably 15+psi)

Can anyone suggest what I may be missing here?

It's starting to get old. All of this because VW put a cr*p turbo on these TFSI cars, one that ends up with a rattling wastegate on overrun (the reason I replaced the turbo).

My patience is all but gone now, replaced and tested almost everything and can't find any faults, no leaks, brand new DV and DV+, new N75, new turbo, new gaskets, PCV deleted, intercoolers and pipework all secured.

I do have a whistle on boost though, which I'm hoping is the problem, if only I could locate the source of it.


The whistle is a mid pitched constant whistle, doesn't rise with revs, not siren-like and not the turbo spooling. Doesn't always do it when boosting and never does it when cruising off boost.

It sounds like and seems like a boost leak but I've checked the system and it holds pressure, the DV is brand new and the pipework has been double triple, quadruple checked.

Thinking maybe exhaust manifold gasket or turbo to catalytic converter gasket as these two were changed when turbo was replaced.


Can anyone make any other suggestions or little tests i can do to isolate the problem?

I tried adjusting the wastegate actuator but tightening it only raises the pressure of the boost spike not the pressure it settles to.

Much grinding of teeth and brain cells, please give suggestions as I'm quickly running out of ideas and motivation.