Turbocharger Adjustment: How To Do It Right

My A6 got a new turbo today and it's running well again. However, it's not quite as responsive as it was before. The mechanic told me to increase the boost pressure slightly by shortening the rod of the variable turbine geometry (VTG) by one turn. Is that okay? Will it actually make a difference, or will the engine control unit reduce the pressure again? I have a P-Box installed. Can anyone electronically increase the boost pressure by about 0.2 bar? Thanks!

Hi,

Changing the boost pressure using the VTG adjustment rod is not a good solution.
You can manipulate it so that the boost pressure is slightly higher than normal, but not so high that the engine control unit enters limp mode. However, this is extremely dependent on weather conditions and air pressure, making it unusable because, in this case, the control system reaches its limit.
For safety reasons, I would advise against doing that, as you always have to be prepared for the engine to stall (e.g., while overtaking).

If the build-up of boost pressure is sluggish, the length of the rods can be adjusted slightly, although this may void the vehicle's general operating permit. However, it is important to monitor the duty cycle of the magnetic valve used for boost pressure regulation using a diagnostic system to ensure that the regulation continues to function correctly under all operating conditions.

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Best regards, Rainer.

... but now I have even more questions: Where is the boost pressure sensor located on my V6 TDI engine, and what resistance should I connect in order to achieve approximately 0.2 bar more boost pressure? I'd rather leave the VTG linkage alone... And who can possibly replace the described resistors in the engine control unit for me, because I don't dare to do it myself? Thanks!

Hi,

Perhaps you should first try to figure out *why* it's performing worse now than before, before you start tinkering with the symptoms by manipulating the sensors. Otherwise, it will become a never-ending project, and future problems are almost guaranteed.

Best regards,

Jan.

Okay, I know I need to be careful. The engine runs well and has plenty of torque. But since I have excess diesel fuel thanks to the PBox, a slight increase in boost pressure would be possible. A friend of mine is a tinkerer and electronics expert and would be willing to help me. He just wants to know exactly where the sensor is located, and what voltage range it reports, or how much increase in boost pressure, for example, a voltage drop of 0.5 volts would produce. Can anyone help me with that? Thanks!