Who offers the highest LD overswing? ZKD hazard?

Hello,

My LD (Low-Pressure) overboost values are around 0.15 bar during the transition from partial throttle to full throttle, depending on the engine speed, which is within the normal range. The VTG is completely intact.

The other day, the Polo actually made me a little nervous.
Contrary to my usual driving style, I was driving with about half throttle and 2200 rpm in 3rd gear to get a specific sound. Hike up a mountain where the atmospheric pressure was 1 bar.
Then I quickly (but not abruptly) pressed the accelerator further, after which the LD (line pressure) increased to approximately 1.8 bar (the LDA scale only goes up to 1.5), but it was by no means "erratically" reduced .

The log data shows a maximum pressure of 2772 mbar for this moment, while the target pressure (LD-Soll) according to the characteristic curve is a maximum of 1.50 bar.
I find that quite excessive... I wonder what my ZK screws will say about it (according to the records, they are the same "soft" ones as in the BPX, which, according to Kenfeld, operates with a maximum of 2.55 bar; only the ARL with a maximum of 1.5 bar has the harder ones)?
The start of boost remains unchanged (and corresponds to the ARL or...). BPX), which prevents excessive pressure spikes from occurring.

Around what LD (load days) does it start lifting the ZK (presumably referring to a specific component or system) without a pre-emptive start-up phase?
Are the screws already undergoing plastic deformation with just one cycle, leading to a decrease in their future peak compressive strength?
Or, based on experience, at what (tuning) scenarios does the plastic deformation of the ZK screws typically begin?

Quote:

Starting approximately at what LD level, without a pre-emptive boost, does it start lifting the ZK?

I'm not exactly an expert in these things. Thinking it through logically, I would say that the combustion pressure is crucial, and that is determined by the amount of fuel supplied.
"The amount of fuel is dependent on it, right? So, if the increased boost pressure doesn't necessarily result in a corresponding increase in fuel delivery, I imagine that the combustion pressure wouldn't increase significantly." I would appreciate it if you could explain how the software handles this and what its limitations are.

It doesn't quite fit the topic, but check out this technical article from ElringKlinger about the relationship between sealing gap oscillation and clamping force: http://www.ekmt.de/fachartikel/0101_mtz.html

Maximum value measured with VAG-COM: 2540 mbar. According to... The LDA stops at approximately 1.5 bar, estimated to be around 1.7-1.75 bar (the gauge is pointing straight down).
However, this happens with every acceleration; there's no frantic adjustment and no emergency mode activation (because the duration is too short).

BM wrote:

But, thinking logically, I would say that the combustion pressure is crucial, and that is determined by the amount of fuel supplied. Fuel quantity dependent, right? If, therefore, not necessarily a correspondingly greater amount of fuel is supplied due to the increased boost pressure, I could imagine that the combustion pressure would not increase significantly.

Well, the injection tips, in my opinion, depend heavily on how much diesel has already been burned in the combustion chamber: that is, on the injection rate (nozzle size!) and the start of injection before top dead center.

But even the compression pressure in the cylinder without combustion depends (of course) on the boost pressure, and is estimated to be proportional to it.

The actual peak pressure (including combustion pressure) likely results from some kind of combination (??) of both processes, meaning that simply increasing the LD (likely referring to a specific parameter) will ultimately have to increase the peak pressure.
I'm just trying to figure out what rule of thumb can be used to estimate "how much."

Overpressure up to 1.6 bar, holding pressure 1.45 bar, and on the first attempt to activate it, it already blew through to the exhaust system. I now have a couple of head studs lying around, but mozz says that the head gasket needs to be replaced as well.

It only spins up to 3500 RPM, and only under full load. It starts with a surge and then continues.

Currently, full-load injection starts at the beginning of the injection cycle, using GT1749VA injectors with a size of 0.216.

Nebelwerfer_TDI wrote:

It only revs up to 3500 RPM, and only under full load. It starts with the overshoot, and then it continues.

Hm, how do you tell when it's reaching its peak power (specifically, 3500 rpm) while driving?

Quote:

Full-throttle injection start is currently standard, using GT1749VA injectors with a 0.216 size.

So, you're saying that the higher (nozzle) flow rate not only causes the peak pressure increase due to LD (likely referring to a specific phenomenon), but also results in higher combustion pressures.
Was your engine originally a 90 horsepower model or a 110 horsepower model?

Ulf.
"With my AHF (likely referring to a specific type of device), I'm using 0.16mm nozzles, a power box with two adjustable levels, and a diode-controlled light intensity (LD) boost. I'm experiencing overpressure situations up to 1.8 bar, which sometimes take a while to regulate back down." I've been driving it for about 80,000 km without any problems.
Sure, here's the translation:

"Hello" or "Greetings"
Harald.

@ulf - you wanted to know who's offering more? I'm offering just as high overspeed values as you are - except for the ARL. Your 130 model should be the same design, so...? Mine should last over 100,000 km.

Hm, how do you tell while driving that it's reaching the point where it's 'blowing through' (i.e., exactly 3500 rpm)?


Combustion gases are expelled from the pressure relief valve, producing a humming sound, similar to the sound you hear when standing near a wasp nest (wasp buzzing is at a higher frequency).

See also ->

So, you're not only experiencing the peak pressure increase caused by the LD (lean deposit) due to the higher (nozzle) flow rate, but also higher combustion pressures.


Yes, however, mine doesn't smoke much more than a standard diesel engine, even with approximately a 90% increase in performance *I'm proud of that* .

Was your engine ever a 90 horsepower model or a 110 horsepower model?http://www.passat3b.de/phpBB2/viewtopic.php?t=52162&highlight=abgehoben

The engine is an AHU.

The head studs are already ready; I'm just waiting for winter (the time for the conversion), and I'm still considering which head gasket to use. Currently, the thinnest one is inside.

Devilseye503 wrote:

@ulf - you wanted to know who offers more? I'm offering at least the same amount of overspeeding as you - only with the ARL. Your 130 should be the same model, though - so why? Mine has already lasted over 100,000 km.

Well, the ASZ doesn't have the extra-hard head bolt screws from the ARL engine... Is your engine tuned or stock?

'Good news: After carefully tightening the cylinder head bolts (120 Nm), the engine is now running smoothly again up to 4000 RPM *happy*.'

Nebelwerfer_TDI wrote:

After I carefully (120Nm) tightened the ZK screws, it's now quiet again up to 4000 rpm *happy*

And over 4000? Not yet tested, or will it fail again?

IMO, your screws are likely to be permanently deformed, meaning they've undergone plastic deformation. And in that state, they'll tend to become softer rather than harder under further (over)loads, if I recall correctly.

@ulf - you wanted to know who offers more? I'm offering at least the same overspeeding values as you - only with the ARL. Your 130 should be of the same design, shouldn't it? So, why? Mine has already lasted over 100,000 km.
Well, the ASZ doesn't have the extra-hard ZK screws from the ARL... Is your engine tuned or stock?

'series. But regarding the extra-hard ZK screws - they used to be different initially, with ARL and ASZ not being 100% identical - the newer ASZ and ARL models should use the same screws. I definitely can't find any other screws for the ARL that are different from those used for the ASZ in the newer engines.'

Devilseye503 wrote:

The newer ASZ and ARL engines should have the same screws - I definitely can't find any other screws for the ARL than the ones used for the ASZ on the newer engines.

According to the records, the ARL engine still had different timing chain tensioner bolts compared to the rest of the 1.9-liter PD TDIs.
Unless the change was only recently implemented...

Where can I find the same screws for the ASZ and ARL models?

And over 4000? Not yet tested, or will it fail again?


Not tested, as I'm going on vacation on Sunday, and I don't want to have the seal blow out before then.

IMO, your screws are likely to be permanently = plastically deformed.

Yes, it seems only the external ones followed suit.

and in this area, they tend to become softer rather than harder with further (over-)loads, if I recall correctly?

Unfortunately, but fortunately, the studs are already . However, I'm more concerned about the screws of the KW bearings. If they give in, then it will all fall apart.

@ulf - I just checked the latest issue of Etos.