Boost Loss A4 2.5 TDI

Hello,

My 2.5 TDI (BAU) engine is losing boost pressure somewhere.

It sounds like there's too much boost pressure during gear changes, similar to the sound of a blow-off valve releasing.
As far as I know, that's not installed.

I've now installed full aluminum LLK (low-latency keyboard) because I've already ruined two of them.

At a certain RPM in a specific gear, you can really feel the loss of power!
Can someone tell me where I might be losing boost pressure? I'm at my wit's end and my nerves are shot!

Thank you in advance.

Hello,

Is the engine tuned? It would be best to create a log showing the target and actual boost pressure values.
When using hose clamps for the charge air hoses, it's best to use high-quality stainless steel hose clamps.
"Damage from martens, especially in areas that are difficult to see, or old, brittle charge pressure hoses can also be the cause."
Leaks in the turbocharger pressure system can be identified by oily, black spots, as oil leaks out from this area. This oil originates from the crankcase ventilation system, which vents into the intake manifold.

Try recording the sound and uploading it here. It's helpful to ride along a wall so you can hear it better.

Sounds resembling a blow-off valve can sometimes be heard during pressure relief after releasing the throttle, but are usually harmless.
"Actual leaks become louder with increasing boost pressure (throttle position): 'Shhhhhh'."

Does the vehicle produce more exhaust smoke than usual during the noise?

Best regards, Rainer.

I understand your post as follows:

Large pressure fluctuations have already damaged two turbochargers. In my opinion, this doesn't necessarily indicate a leak, but rather significant problems with the boost pressure control system.

Rainer's explanation covers what recording "actual" and "target" boost pressure entails, so there's nothing to add in the first instance.

You shouldn't adjust the turbocharger boost pressure. First, you need to identify the error and fix the problem. Everything needs to be in good working order first.