Überschwinger 150 PS (ARL) | Posts 16+

Hi.

Okay, so with my ARL engine, I sometimes have overboost up to 2.1 BAR according to the digital boost pressure gauge. Even with a chip. I've been driving like this for over 30,000 kilometers. And I've never had any issues in that range before.

Sure, here is the translation of the text from German to English:

"MFG" stands for "Mit freundlichen Grüßen," which translates to "Sincerely" or "Best regards" in English. It is a common way to end a formal letter or email.

And a complete log with the tuning file won't help now?

"How is it possible that the engine didn't stall or the turbocharger didn't overspin, even with pressure peaks of up to 3 bar?"

I'm confused. Do I need to subtract approximately 1 bar from the values that VAG-COM displays to get the actual boost pressure? If so, then everything would be okay?

My analog LDA shows the actual LD value, which exhibits overshoot exceeding 2 bar.

3 Phasen Biber wrote:

And a complete log doesn't help me with the tuning file ?

Who should it help, and what is it supposed to achieve? And what do you mean by "completely logging"?
I would estimate that reading the "tuning" file with an OBD tool and examining it would take less time and provide more reliable results. The only problem is finding someone nearby who has a flashing tool...

Quote:

I wonder how it's possible that, even with pressure peaks of up to 3 bar, the engine hasn't stalled or the turbocharger hasn't oversped?

Perhaps the stronger head gasket bolts of the ARL engine are playing a role.
Perhaps the turbocharger has only survived this long because the highest pressure peaks don't occur in the upper engine RPM range, which spares the turbocharger from experiencing the absolute highest rotational speeds.
(also applies to pa-mm6)

Quote:

I'm confused. Do I need to subtract approximately 1 bar from the values that VAG-COM displays to get the actual boost pressure? If so, then everything would be okay? My analog LDA shows the actual LD, which however exhibits overshoots > 2 bar.

Are you confusing setpoint and actual pressure? Your LDA displays the dark blue curve in the log view.

Hi.

Perhaps Rainer can say something about it? I will later test disabling the "chip" and then check the LD display again. I think that the same overshoot peaks will occur here as well. I'll get back to you. I think the original is also like this .

Sure, here is the translation of the text from German to English:

"MFG" stands for "Mit freundlichen Grüßen," which translates to "Sincerely" or "Best regards" in English. It is a common way to end a formal letter or email.

Think about the possibility that the original text is exactly like this.


Ideally, overshoot should be minimal and return to the setpoint within a very short time. 'Minimal' means a duration of no more than 1 second. The magnitude of the overshoot should also be minimal. This assumes that all components are in good technical condition.

ulf wrote:

3 Phasen Biber wrote: And a complete log doesn't help me with the tuning file ? Who should it help, and what is it supposed to achieve? And what do you mean by "completely logging"? I would estimate that reading the "tuning" file with an OBD tool and examining it would take less time and provide more reliable results. The only problem is finding someone nearby who has a flashing tool...

#1 The complete LD (Load Dump) history at various gear ratios.
File #2 is named "noread".
Which tuner will let me see the cards today?
#4 To see if/what is actually defective!

Ulf wrote:

Are you confusing setpoint and actual pressure? Your LDA shows the dark blue curve in the logarithmic representation.

No, I don't.
But that would mean that the actual LD peak values are up to ~1.4 bar above the target value.

Or am I misunderstanding something, and is everything actually okay, with the peaks just being 0.4 bar above the target value?

Oder interpretiere ich das falsch, alles ist i.O. und die peaks liegen bloß 0,4 Bar über soll?

Even 0.4 would be more than too much. That would result in peaks of 2.0 bar at a gauge pressure of 1.6 bar absolute.

3 Phasen Biber wrote:

#1 The complete LD (Load Distribution) profile at various gears. Bitte gib mir den deutschen Text, den du übersetzt haben möchtest. #4 In order to see if/what is actually defective

, your current log already shows me that your tuner seems to be relying on the (alleged) reserves of the turbocharger and engine, rather than putting some time and effort into controlling the overboost. I don't think further logs would bring fundamentally new insights, but you can certainly try if you want.

Quote:

Or am I interpreting this incorrectly, and is everything actually fine, with the peaks just being 0.4 bar above the target?

Partly: While the maximum difference of 0.4 bar between actual and target values is correct (in the previous log), but IMO, it's not okay right now.
Ideally, the difference between the actual and target pressure in the standard configuration should be no more than 0.2 bar, which results in ARL peak values of approximately 1.7 bar, or 2700 millibars when expressed as a logarithmic value.
A good tuner strives to prevent these peaks from climbing further, even with an increase in LD, meaning that the overshoot is reduced approximately by the same amount as the LD is increased.

Edit: I didn't see Mulle's answer in time...

Also sind wir uns einig das es an dem bescheidenem tuning file liegt!

My mechanic said, "There's so much potential left in it..." which, of course, explains a lot!

"I'm also experiencing a strong vibration in the clutch between 1600 and 2000 rpm. He suggested that we might need to reduce the power output to eliminate it."

I heard that this kind of thing doesn't happen at all with good software.

But surely 185 hp / 360 Nm can't be too much for the ARL.


Oh my god... how could I have gone to that tuner? <= Yes, I'm one of those victims.

And perhaps the turbocharger has only survived so far because the highest pressure peaks do not occur in the upper engine RPM range -> this spares the turbocharger from the very highest rotational speeds.
(also applies to pa-mm6)

Hello everyone,

Perhaps we should consider the topic of overspeeding from a speed-oriented perspective and, in that context, consult with someone knowledgeable about turbocharger KV (kilovolts).

The turbocharger only over-revs when it needs to deliver a flow rate that exceeds its capacity.
At 4000 rpm, for example, an overpressure of 0.2 bar would certainly be problematic. However, at 2000 rpm, with the same boost pressure, it only needs to handle half the volume flow. Therefore, according to the 'pi x diameter' principle, an overpressure above 0.4 bar is likely to become problematic. In this case, the pump's limitations are more likely to be the issue.

Important: Both pressure values are examples and do not indicate the actual durability of a turbocharger.

Therefore, I find the statement that pressure surges should not exceed a maximum of 0.2 bar to be somewhat too general.
Even in the standard configuration, the boost pressure is 0.25 bar at 2000 rpm.
This is a common method used by original equipment manufacturers (OEMs) to improve the responsiveness of an engine.

'Extremists need to stay within certain boundaries and have their actions limited.'

@Ulf
As known: -300 and shorter than 6.5.
If this issue were more severe, the boundaries of the OEM IMA would need to be different...


#2 of the file is 'noread'

What's the problem?

#3 welcher Tuner lässt ich denn Heut noch in die Karten gucken?!
Nobody, but that's what we're here for... *g*

Best regards, Jochen.

Therefore, I find the statement that pressure surges should not exceed a maximum of 0.2 bar to be somewhat too general.
Even in the standard configuration, the boost pressure is 0.25 bar at 2000 rpm.
This is a common method used by original equipment manufacturers (OEMs) to improve the responsiveness of an engine.

Die Überschwinger müssen halt im Rahmen bleiben und zeiglich begrenzt sein.

I would bet that these oscillations also occur at different speeds. And 0.2 or 0.25 bar. I wouldn't want to argue about the difference, unfortunately, we are talking about pressures here that are beyond reasonable limits. The pressure reading is also based only on experiences I have seen so far. After a tuning , technically everything is fine, assuming that.

Jochen_145 wrote:

3 Phasen Biber wrote: Permission denied: file " " is "noread".

What's the problem?

Quote:

Is it really not possible to "look inside" the file?

#3 Which tuner will let me see the cards today?
Nobody, but that's what we're here for... *g*

So, it is possible to do it after all. I'm happy to provide the file. My tuner, which I can only positively:D recommend, will probably not be too pleased about this. }

Mein tuner meinte 'da sind so viele Reserven drin...' <= das erklärt natürlich einiges!

This statement is true for an older TDI engine with approximately 90 horsepower.

I don't understand why this is still being directly applied to modern 'high-performance' diesel engines.

Sometimes I wonder how little some tuners understand about the cost management practices of the original equipment manufacturers (OEMs).


I would bet that these oscillations would also occur at a different speed.

Sorry, honey.
I didn't mean to attack you just now.
However, this is not yet clarified. The chart from Ulf shows that the IMA (Image Management Application) was indeed working on the corresponding key value. Unfortunately, the result is not great so far.

Ein guter Tuner bemüht sich, diese Peaks trotz LD-Erhöhung nicht weiter klettern zu lassen, also die Überschwinger ungefähr im gleichen Maß zu verringern, wie er den LD anhebt.

This is actually what I find too general.
I am familiar with the tool called 'Überschwinger.'
You can use this method as long as the turbocharger isn't overloaded by it. (see above)
Therefore, as long as it remains within the realm of technical possibility, it's more a matter of a tuner's signature style than simply being good or bad.
Otherwise, the OEM's sports software will also be inferior to the comfort application.

The problem is that the fundamental approach of considering the oversteering effect is completely correct; however, it's crucial to apply the oversteer correction in a way that truly depends on the speed (RPM).
Most tuners will fail here because this cannot be done using the +/- button.

Best regards, Jochen.

Jochen_145 wrote:

@Ulf As known: -300 and shorter than 6.5. wäre dies Thema schlimmer, müssten die Grenzen des OEM IMA anders aussehen...

Hi Jochen,

since these thresholds...
a) not speed-dependent and
b) They are identical in all the data sets I have searched so far.
I believe this is primarily due to point b), that the original equipment manufacturer (OEM) continues to rely on bundled data packages because not enough has been done so far to change this approach.

If this data were completely harmless, then any charger should be able to disconnect and reconnect arbitrarily often, for example, at 4000 or more rpm during the transition from thrust to full load and deliver arbitrarily high pressures for 6 seconds, slip just below 0.3 bar above the target value at 6.5 seconds, and even above 4000 rpm, constantly deliver 0.29 bar too much}.

"In this scenario, the emergency mode would never be activated – but do you think that a TDI engine with such realistic load behavior, especially when frequently driven at full throttle on the highway, wouldn't eventually suffer turbocharger failure?"

To be honest:

1) Yes, that's actually how it should be, because an increase in boost pressure of 0.2 bar with a 30% power increase is quite normal. The turbocharger can handle this continuously. The maximum power output is likely at the stock engine speed, which is probably around 4000 rpm. I don't think it's running constantly at its 'limit' in that case. Therefore, there should still be a reserve of 0.09 bar to allow for overboost during tuning.
You can find some tuners on the ASV platform that go beyond this value...

Important: these 300 hPa refer to the standard LD model!

2) Personally, I don't want to be approached as a test candidate in order to prove it .

Since this value is not speed-dependent, it must also apply at 4000 rpm. Therefore, according to what was written above, a pressure overshoot of 600 hPa at 2000 rpm should not harm the turbocharger. The resulting mass flow rate would be comparable.

Best regards, Jochen.

Jochen_145 wrote:

because an increase in boost pressure of 0.2 bar with a 30% power increase is actually normal. The turbocharger can handle this permanently. . . . I don't think it's running at its "limit" continuously in this case. Therefore, there should still be a reserve of 0.09 bar to allow for overshooting. Since this value is not speed-dependent, it must also apply at 4000 rpm. Wichtig: diese 300hPa beziehen sich ja auf den Serien-LD !

Okay, the opposite of that would mean: the OEM is foregoing 0.3 bar of maximum pressure (Pmax) that the turbocharger could continuously deliver. For example, in a 96kW TDI engine, this means the turbocharger is only being utilized to 82% of its potential.
This means that manufacturers are using "unnecessarily large" turbochargers, which results in correspondingly "unnecessarily large" turbo lag at low RPMs, even though this is something that the "specialized" press regularly criticizes.

It's quite difficult for me to believe that.