AAZ Turbocharger: High Pressure Issue (2 Bar)

I installed an AAZ turbocharger on my Golf GTD (JR engine).

Everything fit quite well.

When I started the initial test run, the boost pressure gauge showed up to 2 bar under full load (which is within the normal range for that part).

I'm not sure what's causing it, but I haven't touched the wastegate. The screw and nut are still there, just like they were originally!

After that, I tried adjusting the adjustment screw, whether tightening it or loosening it (the threaded rod with the Allen key), but there was no change.
After that, I removed the hose connecting the wastegate to the turbo, and everything seems to be okay.

I can't explain this, but I can't handle this much pressure!

Please help me!!

Best regards, Christian.

Are you referring to the metal pipe that runs from the wastegate to the turbo? I assume it's a metal pipe, since you mentioned there's a screw on the wastegate. There were two turbo types in the AAZ engine, the Garrett and the KKK. The one with the metal pipe had a screw on the wastegate.

If the turbo is actually building 2 bar of boost, it's likely that the wastegate itself isn't opening at all. However, even in that case, I haven't seen it actually reach 2 bar. In my case, the wastegate was once clogged internally within the turbo, which resulted in pressures of 1.4 bar under unfavorable circumstances.

On the other hand, you have 0.3 liters less displacement, so perhaps the turbo generates more pressure due to a faulty wastegate than it did in my case. (Maybe because the engine requires less air? But actually, you also have less exhaust flow.) Or maybe my wastegate wasn't fully closing.

Basically, double-check if the boost pressure gauge is actually working. Try to determine if the boost pressure from the turbo is actually reaching the wastegate. If both of those are working correctly, then the problem must be directly related to the turbo itself, and specifically, to the wastegate.

What was the boost pressure you had with your old turbo? 0.6 to 0.7 bar?

On the old turbo, I had about 0.6 to 0.7 bar of boost. After I increased the boost pressure, it was around 0.9 bar!

The ad is therefore okay, and it's also the original VW testing device!! Also, the turbocharger whistles like crazy, and the car accelerates like a rocket!

The hose to the wastegate was a metal pipe; by the way, it's a KKK turbocharger, so it doesn't have a hose!

There are three Allen screws on the wastegate. We managed to loosen them before, but we couldn't remove the entire wastegate; we could only move it forward about 5cm, and then it stopped.

Can the whole thing be made functional again? Also, how do I remove the wastegate from the turbo?

Thank you, and best regards, Christian.

Unfortunately, I can't tell you how or even if you can remove the wastegate. My solution was to remove the entire turbocharger and clean it thoroughly. However, I'm not a professional in this area, I can only say that it worked for me. Basically, I removed all the dirt that was blocking the wastegate, etc.

Who here in the forum can answer me about how, and whether it's even possible, to clean the wastegate, or how to remove it?

Best regards, Christian.

Hello,

"Perhaps the membrane in the pressure sensor is broken, so the wastegate isn't registering the boost pressure. However, that doesn't explain the 2 bar; I've never seen that much boost before. On my Passat 32b with the Garrett T2-AAZ turbo, I simply disconnected the hose to the pressure sensor because I was too lazy to adjust the pressure properly. It usually produces a maximum of 1.3-1.5 bar, depending on the day."
If the boost pressure starts too late, it will also increase (of course, only if the wastegate is not working properly).

Best regards, Uli.

Okay, then it's probably my wastegate that's broken, and I'll need a new turbocharger. Thanks for the answers anyway!