AGR Engine: Boost Pressure Logging Services Needed

Hello everyone!

My somewhat old problem with the slow build-up of boost pressure in the lower RPM range is really bothering me.
My engine doesn't reach its maximum boost pressure until approximately 2500 RPM. This is the absolute maximum, meaning that the target boost pressure is actually reached a bit earlier, around 2200 RPM (the intersection point between the target boost pressure line and the actual boost pressure line). However, in my opinion, this is at least 300 RPM too late.

To verify my assumption, I need some comparative data, ideally from people who have the same engine (AGR) in their car. Over the past few months, I've noticed a few people here who also own an AGR-powered vehicle.

My appeal to AGR drivers: Please send me your VAG-COM boost pressure logs.

To do this, you only need to log measurement group 11 in VAG-COM during a full-throttle acceleration from the lowest RPM range (approximately 1100 RPM) in a high gear (at least 3rd gear, preferably 4th or 5th). A slight incline is not detrimental, as it prevents the engine speed from being overtaken by the turbocharger. I am satisfied with a log within the RPM range of approximately 1200 to 3000 RPM.

I'm very excited to see the data. My goal is to explore the limitations of the built-in wastegate in the lower RPM range.

Of course, I would also be happy to see boost pressure logs from other TDI drivers with wastegate turbos (1Z, AHU, ...).

Thank you for your support.

Regards,
Alex.

Hello everyone!

Besides the EGR motor boost pressure logs, I am also interested in those of the performance-enhanced versions AHF and ASV.
I would like to know if the target values for these motors differ from those of the EGR system.
Technically speaking, the AHF and ASV turbochargers, due to their variable geometry design, should be capable of generating higher boost pressure at lower engine speeds. However, if the boost pressures are similar in the upper RPM range, it suggests that this potential of the variable geometry turbocharger might not be fully utilized. I want to investigate through direct comparison whether this potential of the VTG turbocharger is taken into account in the boost pressure setpoints defined by the engine control unit (ECU).

I'm getting the impression that the engine control module (ECM) of the AGR system is setting target values in the lower RPM range (idle speed to approximately 2000 RPM) that the wastegate turbocharger cannot achieve.
It's also possible that there is a defect in my turbocharger system. Therefore, I would appreciate it if you could send me as many Group 11 logs as possible so that I can compare them to my engine and assess the mapping of the characteristic curve.

Thank you for your support.

Regards,
Alex.

Hi,

For the ASV project, I have a log file that is 62 KB in size and contains 9 Ulfstests (ranging from 2000 to 4000 in the third test). Last summer, I created diagrams based on this data and posted them here. I've attached the raw data below, as I suspect it might be of interest to others.

The markers indicate the start of each acceleration; between them are decelerations, turns, etc. (I had to go through the log file).

At that time, the car had approximately 12,000 kilometers on the odometer (if I remember correctly), and the EGR system was and still is operational.

Best regards,

Jan.

P.S.: Since the forum doesn't accept files with the *.csv extension, I renamed it to *.txt instead...

Hello Donalexo!

I don't have any log data yet (my VAGCom adapter is still under construction), but I can tell you that...
My LDA (Lambda-regulated catalytic converter) already reaches its target pressure (in my opinion, around 0.9 bar) at the usual 1900 RPM. After that, it remains constant. When increasing the speed from 1000 RPM, there is hardly any overshoot. However, when accelerating suddenly from a cruising state, there is a noticeable increase to about 1 bar.

Best regards,
Ruki

Hello everyone!

First of all, thank you to everyone who has sent me logs so far .

@Ruki:
It would be great if you could send me some log data from the AGR using a working adapter. Unfortunately, I haven't received any AGR log data yet.

@Jan6K:
I was quite surprised to see that the boost pressure setpoints of the ASV are about 100-150 mbar higher than those of the AGR in the mid-speed range. I thought there would be no difference. Perhaps the boost pressure was slightly increased in the ASV compared to the AHF, due to the stricter emission standard (Euro3 for the ASV instead of Euro2 for the AHF), in order to reduce particulate emissions.
Can anyone confirm or deny this? Does anyone perhaps have AHF logging data (Rainer?), to shed light on this matter?

In the attached diagram, I have overlaid the characteristic curves. It is clearly visible that the setpoint values are identical up to approximately 1800 RPM; above that, the aforementioned difference in boost pressure of about 100-150 mbar arises in the setpoint value.
It's also very clear that the VTG turbocharger responds much faster and therefore builds up boost pressure more quickly.
It's important to compare it to an engine with stock injectors that hasn't been modified, because the difference is really significant in that case. Also, you can clearly see that the target boost pressure isn't reached until much later.

Regards,
Alex.

Hi,

If my memory serves me correctly, the AFN (and presumably also the AHF) activates at 2000 mbar, just like the ASV does. Or am I mistaken?

By the way, the diagram is a really interesting comparison between VTG and wastegate.

Best regards,

January.

@Alex: Sorry, I don't have anything suitable readily available.

Hello everyone!

After a long time and with the kind support of some forum members , I would like to take this opportunity again to present the data collected so far in a (somewhat cluttered) graphic.
Here's the translation:

"You can see a direct comparison between my EGR system with its slow boost pressure build-up, the "normal" boost pressure build-up of an EGR system, the behavior of an EGR system with a 10-cent tuning modification, and in contrast, an ASV engine."
All the Wires were logged during a Differential Zero-Crossing (DZR) test at the same level on the 3rd floor, so they are directly comparable.

I find it remarkable that the pressure increase of the wastegate turbocharger is no less than that of the VTG turbocharger (when the same exhaust mass flow rate is enforced -> a "10-cent" tuning). However, the VTG turbocharger can already produce higher boost pressure at lower engine speeds. This is very clearly visible.

To complete the overall picture, we still need DZR (Data Zone Recorder) logs from both the AHF (presumably a specific engine type) and the ALH (another engine type). Then, we would have the ultimate comparison with an identical mechanical engine platform.

Another (bitter) realization for me is that I definitely have a problem.
I have now made suitable sealing plugs for the charge pressure hoses on the intake manifold and at the compressor outlet. One of the plugs has a tire valve and a pressure gauge connection. I still hope that with these tools, I will be able to find a leak. It would really be unfortunate if it turns out to be due to the turbocharger .

Keep your fingers crossed for me!

Oh, I'm still happy to receive any posted log file for the engine codes that are still missing .

Regards,
Alex.

Hello everyone!

After a long time and with the kind support of some forum members , I would like to take this opportunity again to present the data collected so far in a (somewhat cluttered) graphic.
Here's the translation:

"You can see a direct comparison between my EGR system with its slow boost pressure build-up, the "normal" boost pressure build-up of an EGR system, the behavior of an EGR system with a 10-cent tuning modification, and in contrast, an ASV engine."
All the Wires were logged during a Differential Zero-Crossing (DZR) test at the same level on the 3rd floor, so they are directly comparable.

I find it remarkable that the pressure increase of the wastegate turbocharger is no less than that of the VTG turbocharger (when the same exhaust mass flow rate is enforced -> "10-cent" tuning). However, the VTG turbocharger can already produce a higher boost pressure at lower engine speeds. This is very clearly visible.

To complete the overall picture, we still need DZR (Data Zone Recorder) logs from both the AHF (presumably a specific engine or system) and the ALH (likely another engine or system). Then, we would have the ultimate comparison with an identical mechanical engine platform.

Another (bitter) realization for me is that I definitely have a problem.
I have now made suitable sealing plugs for the charge pressure hoses on the intake manifold and at the compressor outlet. One of the plugs has a tire valve and a pressure gauge connection. I still hope that with these tools, I will be able to find a leak. It would really be unfortunate if it turns out to be due to the turbocharger .

Keep your fingers crossed for me!

Okay, I'm still happy to receive any posted log files for the engine codes that are still missing .

Regards,
Alex.