LLK Temperature During Load: When Does STG Throttle?

Hello,
"Does anyone have any experience with the intercooler temperature on a TDI with the original intercooler? Specifically, what are the typical temperatures: 1. at high speed, and 2. at low speed and high load (e.g., going uphill) with warm ambient temperatures?"
At what temperature does the turbocharger start to intervene? Does it do so abruptly, or does it regulate continuously?

Hello.
Carsten.

Hello Carsten!

As far as I know, there is no upper limit for the intake air temperature at which the MSG (Motor Slip Guard) intervenes and reduces boost pressure or injection volume (please correct me if I am wrong).
However, this effect occurs indirectly anyway, because at high intake air temperatures, the mass flow decreases due to the lower density (while the volumetric flow remains the same). This is registered by the mass airflow sensor (MAF), which then reports less oxygen to the engine control unit (ECU) for combustion. Once the threshold of the opacity characteristic curve becomes the limiting factor, the injection quantity and thus the power output also decrease.

Regards,
Alex.

I logged the temperature in the intake manifold (1Z) while driving on the highway for over 150 km.

Under low load, the temperature difference between the device and the outside temperature was smaller (as measured with a separate thermometer).

During high-load conditions on the mountain, the temperature was 30 degrees Celsius above the outside temperature (outside temperature was 7 degrees Celsius, charge air temperature was 37 degrees Celsius).

This is roughly consistent with Rainer K.'s measurement data regarding improved ventilation for low-lying vehicles on the A3 highway.

m;

@Martin,
Thanks for the information. So, the maximum increase in temperature is approximately 30-40 degrees at high speeds.


It would be interesting to compare the results under full load, for example, while towing a trailer. But I can see that I still need to do something; with my current solution, I'm getting temperatures of around 50-70°C under a good load, and even a fan won't help.

@donalexo
Well, I think the LMM isn't suitable for an appropriate limitation. Its signal depends much more on the EGR than on any temperatures, that's my impression, but I haven't performed any thermodynamic analysis .
The LMM signal is obviously set precisely to a 50% EGR rate; otherwise, the desired and actual mass flow would deviate significantly. Of course, it's possible that this is recalculated based on the duty cycle, and a temperature dependency can still be detected......[/quote]

http://www.ralfhandel.de/images/autobahn.jpg
http://www.ralfhandel.de/images/messfahrt4-temp.gif

I also have the mentioned features (1Z, cruise control, outside temperature display - it must have been -3 degrees).




Here's the 7-degree image, same route, different day.

'Where can I find the charge air temperature measurement within the ALH system? Is it perhaps the intake manifold temperature in block 7 (I believe)?'

Sure.
The intake manifold temperature reading seems good; that's the one.

m;