Nebler vor dem LLK-Einlaß :-(((( | Posts 16+

Fortunately, in addition to the four 1J models for golf, there is still the ARL .

My bad... that one still exists, and the LLK (Low-Level Coolant) is located in the middle, in front of the air conditioning condenser. However, the grille on the driver's side is still closed.

As you can see in the R-Line model, everything is exposed.
Whether it's good or not (regarding turbulence), there's enough airflow everywhere.

On the original R32, the grilles on both the driver's and passenger's sides are only subtly indicated, but are solid.

As you can see in the R-Line, as mentioned above, everything is exposed.
Whether it's good or not (regarding turbulence), there's enough airflow everywhere.


I'm assuming the starting point is the standard configuration of a Golf4... that above is definitely an aftermarket bumper.

The R32 is also a naturally aspirated engine, so what does it mean for it to be 'open' at low RPMs?

@ Julian

Okay, I want to state that the VW Bora 1.9 TDI PD (85kw) AJM engine is equipped with a turbocharger. It is correct that the intercooler is located on the passenger side, quite close to the fender. However, I won't just use my influence on this page; what would that look like ?

You're probably right, and maybe the wrong grid was on it. But what do I know? I don't know what kind of grid should be there. This is my first T-Diesel.

You are also right that dirt can enter the engine compartment through the air vents. Does it make that much of a difference compared to the standard grid (open version)?

I have not experienced any problems with gravel ingress, and I have had the inlets for a year. However, I acknowledge the possibility that the risk of gravel ingress may increase. Does that also apply to the grid?

Okay, I've been looking into the air ducting for the liquid cooling system.

In the attachment, the original (left) and modified (right) flow cross-sections for the LLK are marked in red – however, only the areas that I have significantly revised.
(New image on page 2 of this thread)

Closer than it appears in the photo, the factory-installed route from the inner grid section ran diagonally behind the fogger to the LLK (lower left corner) (photo below left).


In addition, there were almost everywhere gaps of approximately 1 cm in the air ducts, where the parts that formed the duct did not touch each other. Probably so that the whole thing can be assembled more quickly, without getting stuck somewhere.

As you can see in the picture of the radiator (top right), it presents a large surface area to the cooling air, but with relatively few passages. In my opinion, this means that a certain amount of back pressure is required for the cooling airflow to properly circulate within the radiator.

However, due to the aforementioned slots, the developing back pressure could easily escape, which is why I'm not surprised anymore by the limited effectiveness of the LLK.

Therefore, in a subsequent step, I filled or glued the gaps with foam.

When I have another opportunity to access data logs, I will post the results.

Hello,

I find fog lights to be quite unnecessary since I got xenon headlights.

Sincerely,
Christian

I was in a situation where, after an accident, the wrong parts were installed on my car, just like Jan6K mentioned. I only realized recently that I couldn't see the LLK (likely referring to a specific component). I then had the relevant part removed. However, it didn't result in any noticeable improvement in performance or reduction in fuel consumption...

DocSnydor wrote:

I then resigned from the relevant position. However, it did not result in any noticeable improvement in performance or a reduction in fuel consumption...

My logs, which now contain approximately 650 individual samples, indicate similar results.

It is clearly discernible that above ~3700 rpm and 70°C LLT, the boost pressure is reduced (down to approximately 100 mbar per 10°C), but this does not yet cause the soot limit to fall below the torque limit -> no reduction in the injection quantity.

Therefore, the only advantages lie in a reduction of the average combustion chamber temperatures, but this apparently does not have a noticeable effect in everyday use.

The only advantages lie in a reduction of the average combustion chamber temperatures, but this apparently does not have a noticeable effect in everyday use.

Hi,

Perhaps that's one of the reasons why it's truly needed. It reduces the combustion chamber temperature, which in turn lowers NOx emissions. Perhaps we could eliminate the LLK (low-pressure charge cooler) and, at the same time, increase the boost pressure slightly to get the same amount of air into the cylinders.
The question is whether such an engine could meet the legal requirements.

Greetings.

Eike.

hm...

Why was LLK (likely referring to catalytic converters) already being used when there were no emission regulations yet?



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

'Cu Gremlin'

Hi,

Furthermore, you can often extract more performance from tanks without liquid cooling (LLK) by adding liquid cooling systems.

I suspect that the LLK (likely referring to a specific component) is simply oversized for the series performance in order to compensate for potential design flaws in the peripheral components (specifically, the air supply). It's probably cheaper than using a smaller LLM with an optimized environment.

Best regards,

Jan.

Jan6K wrote:

I think it's simply the case that the LLK (likely referring to a specific component) is oversized for the nominal performance to compensate for potential design flaws in the peripherals (air supply).

Well, the difference between the factory-made design and my flawed design results in about 10°C of lower latent heat.

On the country road, number 3. Currently, the temperature is reaching up to approximately 67°C at full throttle (up to 4300 rpm) with the installed misting system.

Previously, under practically identical measurement conditions, the temperature was 78°C with the humidifier on and 73°C without the humidifier, always with outside temperatures around 17°C (which made today a good opportunity for testing).

EDIT 31.7.04:
More details can now be found and viewed at:

Okay, I'm ready. Please provide the German text you want me to translate.

Gremlin wrote:

Why was LLK already used when there were no exhaust emission regulations yet?

You've already answered that elsewhere, in keywords, .

But let's talk about something else:
Is there an optimal low-temperature combustion (LTC) range for turbodiesel engines, where the most important engine operating parameters (whatever they may be) are within the optimal range at peak pressure (Pmax), and which should therefore be targeted through LTC?

Hello,

I tried to roughly calculate the change in LLK (Low-Temperature Coolant) effect caused by my modifications to the air ducting, and I would like to discuss this here – also considering the likely sloppy construction of the LLK air ducting in the Polo 9N .

As a computational model, I used the analogy of a voltage divider (now things are getting very theoretical).

- The ambient temperature corresponds to the circuit's zero point.

- The increase in intake air temperature caused by the turbocharger corresponds to the input voltage Ue.

- The difference between the liquid level temperature (LLT) and the ambient temperature corresponds to the initial voltage (Ua).

- The thermal resistance of the coolant (°C / kW) corresponds to the "lower" potentiometer resistance R2.

- The temperature change of the charge air, depending on the cooling capacity (°C / kW), corresponds to the "upper" potentiometer resistance R1 - of course, only with a constant air mass flow rate.

I developed the LLK calculation based on the Poti formula: Ua / Ue = R2 / (R1 + R2).

Resolved based on R2 (corresponding to the thermal resistance of the heat transfer fluid).

R2 = (Ua / Ue) * (R1 + R2)
R2 = R1 * Ua / Ue + R2 * Ua / Ue
R2 - R2 * Ua / Ue = R1 * Ua / Ue = R2 * (1 - Ua / Ue)
R2 = (R1 * Ua / Ue) / (1 - Ua / Ue)

If one only wants to calculate the ratio of several intercoolers' thermal resistances (electrically: R2a and R2b), R1 (corresponding to the here assumed constant °C/kW value of the intake air) can be replaced by 1.

R2a / R2b = (Uaa / Ue) / (Uab / Ue) * (1 - Uab / Ue) / (1 - Uaa / Ue)
In this case, Uaa and Uab are the initial voltages, which depend on R2a and R2b.

Abbreviated and calculated, the result is:
R2a / R2b = (Uaa - Uaa * Uab / Ue) / (Uab - Uaa * Uab / Ue)


The ratio of thermal resistances or the effectiveness of the liquid cooling system (LLK) is calculated based on the modifications made to the LLK.

(Taa - Taa * Tab / Te) / (Tab - Taa * Tab / Te)

Sure, I'll translate the text for you. Please provide the text you would like me to translate from German to English.

-> Taa or Tab represents the difference between the liquid level temperature (LLT) and the ambient temperature during measurement a or b. Measurement b.

-> The increase in charge air temperature is due to the pressure increase: Te = Δp * 75K (p in bar).

In this (certainly roughly simplified) calculation, I used the values Te = 97K and Ta of 58K and 68K, respectively (measurements taken with a humidifier upstream of the LLK inlet).

This results in a change in the LLK (liquid cooling) effect by a factor of approximately 1.57 – meaning that the effect of my LLK has increased by about 57% compared to the standard configuration due to the modifications made to the airflow!

In other words, the LLK (likely referring to a component or specification) of the Polo would have to be oversized by about 1/3 from the factory if the LLT (likely another component or specification) is to remain within the intended range under real-world installation conditions... assuming my calculation is fundamentally correct.

Your comments?