Cooling Charge Air: Ideas & Tips

Hello everyone,
Does anyone have any ideas or experience on how to cool down the intercooler on my Golf 4 TDI with an ALH engine? What is a larger intercooler that would fit? Has anyone ever considered using Peltier elements? Could that work?

Hi,
You can completely forget about using Peltier elements. I don't have any specific numbers regarding power density and efficiency, but for example, my cooler box takes almost a whole day to cool down a lukewarm bottle!
The power loss due to electricity consumption will negate any theoretical performance gains.
Spraying the LLK (likely referring to a heat sink) with water would be a cheap and effective way to cool it, but I suspect that the outer surface area of the LLK is too small to provide a truly noticeable cooling effect.

Okay, so I can forget about the Peltier element. In my opinion, the water spraying method is too inconvenient because I would constantly have to refill water and install a tank somewhere. I drive 2000 km per week!!! Has anyone ever tried using a motorcycle radiator fan? It's nice and small and provides a good amount of airflow! But wouldn't it also draw too much power, so that there's no actual performance gain?

Best regards.
Stefan.

@tdifuzzi:
I had also considered this approach before. However, I have come to the conclusion that installing a radiator fan is not very useful.
This is because, firstly, the installation space is very limited (especially in Audi A3, G3, and G4 models). The airflow behind the intercooler leaves very little space towards the wheel arch.
IMO, the auxiliary fan would only offer an advantage in city traffic and at very low speeds. However, in those situations, you usually don't need to squeeze every last bit of power out of the engine. If you, on the other hand, enjoy quick acceleration from traffic lights in the height of summer without any hesitation, then the auxiliary fan might be beneficial for you! (However, it wasn't a decisive factor in my decision.)
Considering the typical speeds of common fan types and the maximum diameter of a fan that can be installed behind the radiator, I believe that an improvement in airflow is likely to occur only up to a speed of 50-60 km/h. At higher speeds, the fan will likely create more resistance to the airflow than it provides assistance.
Well, as you correctly pointed out, you don't get the fan's power for free. The balance here is also unfavorable, because the electrical power consumption of the fan motor must ultimately be generated by the engine, and this involves significant losses (efficiency of the alternator). I believe that the remaining performance gain is negligible due to improved intercooling.

My motto: Improving the performance of liquid cooling systems can only be achieved efficiently through increased surface area, meaning a modified liquid cooling system. Anything else is largely ineffective.

Regards,
Alex.

Peltier elements also generate a significant amount of heat on the back side. I once experimented with them to cool the chip in my computer to very low temperatures. The Peltier elements get extremely hot after a short time... effectively dissipating that large amount of heat can only be done with water cooling.
How about trying to cool the air that flows through the liquid cooling system? Or perhaps using a second or larger liquid cooling system, possibly powered by the ARL (Auxiliary Power Unit)?

Is there a larger radiator available for the Golf 4? Roughly how many horsepower would it add? Does anyone else know of any sources for larger radiators that fit in a G4?

Best regards.
Stefan.

ARL? What kind of engine is that? I've never heard of it before! But there's very little space for a second air conditioning unit, right? Where would you even install one? There's already the auxiliary heater on the driver's side.

Best regards.
Stefan.

tdifuzzi wrote:

Is there a larger LLK (liquid cooling system) available for the Golf 4?

Yes! If necessary, you can also use two of them (one on the right, like in the standard configuration, and one additional on the left).

Quote:

What will the approximate horsepower be?

Nothing!
Without adjusting the boost pressure and fuel injection volume to match the modifications, the performance gain will likely be minimal. Use the search function; we've discussed this many times before!
In the summer, a larger LLK (presumably referring to a specific type of device or treatment) may lead to a reduction in the "summer weakness" effect.

Quote:

ARL? What kind of engine is that? I've never seen one like it before!

Then do some research beforehand! The ARL is the 110kW PD TDI engine!

Quote:

There's very little space available for a second battery, right? Where would you even put it? The auxiliary heater is already located on the driver's side.

If the auxiliary heater is located on the left side, it will be difficult to install a second auxiliary heater.

Hello everyone,

"Also, try searching for a thread by Rainer. He experimented with improving the airflow to and from the rear window (LLK) in an A3 a while ago, making changes to the mudguards and wheel arches. If my memory serves me correctly, he concluded that, despite visibly improved airflow (meaning significantly more wind on the LLK), it didn't result in any measurable improvement."

Best regards,

Jan.

The 110kW version has an optimized liquid-liquid heat exchanger (LLK), located between the air conditioning condenser and the water cooler. As far as I know, the optimized LLK has a thermal efficiency that is about 15 percentage points higher than the 85kW version. Consequently, the temperature after the LLK was at the same level as the 85kW version, despite the higher thermal load. Before the LLK, the difference was 25°C. Therefore, by replacing the LLK, you should also achieve better cooling.