Boost Pressure Increase: Diode Method Alternatives

Hello,
Yesterday, I tried to increase the boost pressure on my G4 (TDI AHF with an auxiliary control unit from Princiotta, switchable in 2 stages from the interior, and a mechanical LDA). I did something different from what has already been posted here: instead of inserting the diodes into the output signal of the pressure sensor, I lowered the +5V signal to +4.2V using 3 diodes connected in series. However, the result is disappointing; there was only a very small increase of at most +0.05-0.1 bar. What could be the reason?
Does the pressure sensor compensate for the lower supply voltage in any way?
I thought that by doing this, I could avoid shifting the entire boost pressure range to higher values, but I guess I was wrong?
I'll try resoldering it tomorrow, following the instructions described in this forum.
Sure, here is the translation of the text from German to English:

"Hello"
harald

hharry wrote:

There was only a very slight increase, at most +0.05 to 0.1 bar. What could be the reason?

Perhaps it's due to the rule strategy of the EDC system, which (depending on the specific machine control or software) doesn't completely correct LD deviations.

I assume you read those +0.05 to +0.1 bar values from an LDA.
Have you already logged the LD data (with and without diodes)?

As far as I know, the LD sensors are only specified for an operating voltage of 5V. If you operate them with 4.2V, it's possible that they will still output the same voltages for the same charging pressures, but the maximum value will be lower. In the extreme case (or with additional diodes), this could simply limit the maximum pressure, preventing the EDC from regulating the charger properly, or causing the charger to operate at its maximum output.

So, just plug the diodes into the output branch, as described here. Or, you can control it directly using a chip ;o).

Regards,
Guste.

Hello,
Okay, I've now re-soldered and inserted two diodes into the signal path. The result was: the boost pressure was far too high, with overshoots up to 1.8 bar, then settling at a constant 1.4 bar.
After removing a diode, the system now seems to be working optimally. The pressure overshoots to 1.5 bar and then stabilizes at a constant 1.2 bar.
However, I couldn't detect a noticeable shift of the entire pressure range upwards. The airflow has improved slightly, and there is hardly any soot, even with full acceleration.
Sure, here is the translation of the text from German to English:

"Hello"
harald

Hello Ulf,

I can't create any logs with my outdated software. Years ago, I think around 1998, I bought one of the first diagnostic adapters directly from Uwe Ross in the USA. Along with it, I received a shareware program, which, however, was no longer developed, and which Uwe used as the basis for his VAG-COM.
Back then, I used to drive a VR6, and Uwe used to sell tuning chips from Garrett (www.giacusa.com).
I should probably get a current (licensed) version of VAG-COM.
Sure, here is the translation of the text from German to English:

"Hello"
harald