ALH + 205 ASV injectors + 11mm pump plunger => boost pressure?

Hello.
I drive a Golf IV with an ALH engine. I've installed ASV injectors, and now I have about 110 horsepower. That's pretty good so far. Now I'm considering switching to 11mm pump plungers. I think I would end up with around 130 horsepower, right?
"The problem is that with so much diesel being injected, I still need to increase the boost pressure by 0.2 to 0.3 bar... otherwise, it will produce excessive smoke. The car already smokes a bit with the other injectors due to the relatively low-quality fuel I'm using. I don't want to do any chip tuning because engine control units (ECUs) that are specifically tuned for injectors and pump plungers are rarely approved for road use, and because modified, non-approved ECUs can be quickly detected in the worst-case scenario. Injectors and pump plungers, on the other hand (I think), are less likely to be an issue." Of course, that is also not allowed.

So, how can I consistently achieve 0.2 to 0.3 bar more boost pressure than before, without modifying the turbocharger? I once read something about tampering with the turbocharger pressure sensor signal, but I couldn't find anything specific about how it's done on an Alh model.
Okay, here's the translation:

"So, how harmful do you think this tuning is for the engine? I believe it's gentler than regular chip tuning, and I'm actually only worried about the clutch – what do you think?" Thank you.
Best regards,
Bernd.

Hello Bernd!

Quote:

I drive a Golf IV ALH. I installed ASV injectors, and now I have about 110 horsepower. That's quite nice so far. Now I'm considering switching to 11mm pump plungers. I think I would end up with approximately 130 horsepower - is that correct?

Yes, I completely agree!

Quote:

The problem is that, with so much diesel being injected, I still need a boost pressure increase of 0.2 to 0.3 bar... otherwise, it will produce significantly too much black smoke.

I think that's a bit too high. 0.1-0.2 bar should be sufficient; otherwise, you risk damaging the engine due to excessive peak pressures.

Quote:

How harmful, do you think, is this tuning for the engine? I believe that it is gentler than normal chip tuning, and I am actually only concerned about the clutch - what do you think?

With a combined injector and pump tuning, I would be seriously concerned about the connecting rod bearings, the head gasket, and the head bolts. The engine will certainly not fail due to a piston seizure caused by excessive fuel injection, however, the pressure increase in the cylinder will be extremely high, as approximately 50% more fuel can be injected in the same amount of time.
In a mixed process (thermodynamics), you increase the volume fraction while keeping the constant pressure fraction constant. In chip tuning, the proportion of boost pressure is typically increased.
In terms of efficiency, meaning performance/consumption, this approach is optimal. However, the mechanical stress on the components increases dramatically. The thermal stress on the engine is significantly increased, while the exhaust gas temperature is only marginally affected.

I would be very cautious about performing such a tight tuning modification on an ALH engine, as it does not yet have the reinforced upper sputter layers on the connecting rod bearings. The existing oil-coolant heat exchanger is likely too small for this level of performance.

I'd also be interested in hearing about the acoustics of an ALH engine that's been modified like that. The engine's running sound is likely to be very harsh and metallic due to the large combustion chamber volume. Simply changing to larger nozzles significantly alters the sound.

Regards,
Alex.

@ Alex

Thank you for your statement. So, you believe that increasing the engine's performance to 130 horsepower using a chip tuning would be gentler on the engine? Your statements sound logical - which is a shame, actually .
I guess I'll have to go to the hospital after all...

Hello Bernd!

Quote:

So, you believe that increasing the engine's power to 130 horsepower using a chip would be gentler on the engine?

No, I didn't phrase it that way. I simply believe that combined nozzle and pump tuning exceeds the machine's mechanical load capacity.
Increasing the power from 90 to 130 horsepower solely through a chip tune is also not good for the engine, as the injection time will definitely become too long in this process. This could put the pistons at risk, as well as the turbocharger due to the increasing exhaust temperatures.
Furthermore, the engine's efficiency drops significantly because the fuel injected late in the cycle is not utilized effectively (due to the pressure equalization during the combustion process).
Some tuners are now counteracting this by significantly advancing the injection timing, which in turn increases the mechanical stress, but reduces the risk of piston melting.

You can see that you can't make a blanket judgment; it depends on too many factors. One would need to analyze the tuning parameters of the chip tuner in order to assess the effects.

My suggestion for you: Why don't you try the combination of large nozzles (which you already have, right?) and a modest, inexpensive tuning adjustment? If it's smoking too much, you can still manipulate the boost pressure sensor signal to increase the boost pressure by 0.1-0.2 bar.
This is undoubtedly the most straightforward solution, and you have complete control over all the parameters. It allows you to achieve a good balance between durability, efficiency, and performance. Above all, this 10-cent tuning can also be implemented as a switchable feature (and naturally combined with a switchable boost pressure signal modification), so that, for example, the higher performance can be activated only when needed.

Regards,
Alex.

Hello.
Thank you for your effort...
Okay, so the ALH engine should theoretically be able to handle 130 horsepower – even though you might think it shouldn't. In other diesel forums, people are running the ALH with 180 horsepower, and it's been working for a while... I couldn't believe it either, but it seems to be possible. Many people have 150 horsepower, and I'm pretty sure it's not just talk (even though it's sometimes exaggerated). But I think many of those people aren't driving their ALHs at 160-190 km/h on the highway 80% of the time.
"130 horsepower should be sufficient, but a manual transmission would be even better... I'd like more torque for quick driving on country roads with nice curves, etc. I don't need the extra fuel injection to drive at 180 km/h on the highway, as it already revs up (almost) to its redline. So, it won't be faster anyway - and that's fine!" Okay, enough about that...

Okay, so larger injectors (205 ASV) are available, yes. Also, I once bought a used KW-systems powerbox. It's switchable and has a potentiometer to adjust it yourself. I bought it because it was cheap. I've preferred the nozzle solution so far.
I'm not sure what the effect will be if I install the box in addition to the nozzles. Do you really believe that this is fundamentally not a problem?
"I'll definitely need to increase the boost pressure. So, I'll add 0.2 bar more boost and adjust the potentiometer until I believe the emissions are within a road-legal range. With that, I should be able to achieve approximately 130 horsepower, right?" And does the motor drive this type of pump more effectively than it drives the other pump pistons?
Sure, I enjoy tinkering and yes, I'd like more power, but first and foremost, I want the engine to be reliable.

The box is still eligible for registration. It's not actually that bad.
Now I just need to know how to manipulate the boost pressure sensor signal. I recently had the donor in my hand...
Unfortunately, I can't find any information anywhere on how to proceed. Can anyone help me? Thank you very much!

Marzocchi,

You're right to be concerned about the clutch. I believe it can handle a maximum of around 310 Nm of torque. I myself have a Leon Alh with original injectors, size 0.184, producing 123 hp/310 Nm (with new software). So, you can easily achieve 130 hp with 0.205 injectors. Next year, I'm also switching to 0.216 injectors (with completely new software) and expect at least 150 hp/370 Nm. And regarding the clutch... do you have any ideas?

There are reinforced clutches available from Sachs or All4TDI.
What interests me more here is the increase in boost pressure achieved by covering the sensor.

There are reinforced clutches available from Sachs or All4TDI.
What interests me more here is the increase in boost pressure achieved by covering the sensor...

I currently have a maximum of +0.15 (which is measured by software), but I wouldn't feel comfortable using a bed sensor .

Well, whether the boost pressure is constantly increased via software or whether the signal from the sensor is distorted as a result, it shouldn't really matter. You can control it using LDA.
It's likely that the VTG rod will need to be machined slightly shorter to prevent over-swinging.

Is there really no one here who knows how it works?

Hello Bernd!

Without delving into the specific electrical specifications of the sensor, I believe a simple voltage divider circuit will suffice.
The boost pressure sensor provides an output voltage that is proportional to the pressure (likely 0-5V). If you use a voltage divider circuit to manipulate the sensor's output, you can simulate a specific pressure. For example, you could configure the circuit so that the voltage at the sensor's output is the same as the voltage that would normally be present at 1 bar, but this is achieved at a pressure of 1.2 bar. It can be implemented using just two resistors!

Regards,
Alex.

Everything's fine. I'll take a look at that soon.
It would be nice to find someone here who has more experience with electronics than I do, and who has done something similar before. Then I would know in which ranges I should adjust the resistance to achieve about 0.2 to 0.3 bar more (the default setting is 0.95 bar). But thank you very much!

However, the following should be taken into consideration:
The sensor measures absolute pressure. Therefore, you will also see an increase in boost pressure at idle. For example, if the maximum boost pressure increases from 1 bar to 1.2 bar, you will have 0.1 bar of boost pressure at idle instead of 0 bar. However, this cannot be achieved without sufficient mass flow, and it may end up in emergency mode.
It's just a thought, but I think it could potentially become a problem.

Well, whether the boost pressure is now controlled constantly via software

You are mistaken.

It's not constant, but I wrote a maximum of +0.15. I got that +0.15 value for the maximum speed (v max), which is an advantage compared to the sensor distortion mentioned above.

"The amount of distortion you're seeing isn't likely speed-dependent; it's probably more related to engine RPM. I'm injecting a constant amount of fuel through the injectors, so I think I can probably handle a constant increase in boost pressure as well."

Now I'm thinking about switching to 11mm pump pistons. I think I would end up with approximately 130 horsepower - is that correct?

Have you done it yet? If so, where did you get the plunger and how does it work in practice?

Hi,

How is the engine in terms of power delivery? What is its exhaust behavior? 'Stress test?'

Best regards.