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AFN: Is 1.3 Bar Overshoot Safe?

 
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rl2664
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Post19-12-2003, 0:09    Subject: AFN: Is 1.3 Bar Overshoot Safe? Quote

Hello.

'I installed my LDA today, and I noticed that it sometimes shows overboost values, up to 1.3 bar! Is this normal, or should I adjust the VTG adjustment slightly further?'
The boost pressure only reaches that level for a moment and then immediately regulates back down to just below one bar.
Opinions?

best regards
Ronny.


Translated on 02-10-2026, 8:37.
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Golfmann
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Post19-12-2003, 1:39    Subject: AFN: Is 1.3 Bar Overshoot Safe? Quote

When it's directly adjusted to 1 bar, that's almost normal.
I wouldn't worry about that.
It's also possible that the LDA (Lambda-indicated air flow meter) is malfunctioning. That's what's happening with mine. It's showing overboost values up to 1.3 bar. However, VAG Com only shows a maximum of 1.2 bar. I think I'll trust the VAG Com in this case, as the hose leading to the control unit for pressure measurement is shorter.


Translated on 02-10-2026, 8:39.
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rl2664
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Post19-12-2003, 10:07    Subject: AFN: Is 1.3 Bar Overshoot Safe? Quote

I was just on the highway...
I think I'm going to increase the VTG (Variable Turbine Geometry) setting a bit more. Under normal operation, the pressure overshoots up to 1.3 bar, and on the A-bahn line with a 10-degree incline, the needle sometimes even reaches 1.5 bar. I suspect that this isn't ideal for the turbocharger in the long run...
What surprises me is the following: When I accelerate hard in the A-Bahn and activate the '10c' setting, the regulated boost pressure increases from 0.9 to 1.1-1.2 bar. Is this normal?

best regards
Ronny.


Translated on 02-10-2026, 8:40.
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dieselschrauber
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Post19-12-2003, 11:24    Subject: AFN: Is 1.3 Bar Overshoot Safe? Quote

Hi, I suspect the lever arm might be a bit too short, considering how much higher the LD reading is with a 10C setting. Could you check the duty cycle of the solenoid valve to see if it's already close to its limit?

Best regards, Rainer.


Translated on 02-10-2026, 8:41.
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rl2664
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Post19-12-2003, 11:43    Subject: AFN: Is 1.3 Bar Overshoot Safe? Quote

Hello Rainer,

I've now adjusted the lever back to its original length. It's better now. However, the boost pressure is still at the same level (10 bar). The overboost events are generally 0.1 bar less aggressive.
I can't say yet what the keying ratio is, but I hope my OBD interface arrives in the mail today...

best regards
Ronny.


Translated on 02-10-2026, 8:42.
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