Water Temperature After Tuning: Optimization Tips

Hello,

To get away from the 130 -> 160 PS thread for a moment:

According to the documentation, the different performance levels (at least for the PD model) also have different water pumps.
According to Wendland's tuner, the water flow rate increases with the factory's output.

This would mean that, conversely, tuned engines with the then "too small" water pump would have to run hotter in the Pmax range than with the standard power output - which, unfortunately, can only be detected with a diagnostic device / VAGCOM thanks to the ingenious ramp function of the newer AI displays.

Has anyone in this forum performed data logs (before and after tuning, or at different power levels, both normal and increased) that would allow for a meaningful comparison?
Whether the logs come from your own car or, for example, from a friend, is of course irrelevant .

It would be interesting for me (and hopefully for some others here) to know how much the temperature (K) would change if VAG used a larger pump.

So, regarding the AWX, I've already sent you some data, and as far as I know, the water temperature didn't increase at all.

In my humble opinion:

I doubt that a higher coolant flow rate will make much difference, because water can only 'absorb' the engine's heat within a certain time frame. More importantly, the cooling surface area needs to be adequately sized.

The radiator is already installed in even the most powerful model (or, to put it another way, there's only one water-cooled radiator available for all engines), so it's recommended to install a thermostat that opens earlier (approximately 5-10°C earlier, depending on what's available on the market).

Julian wrote:

Regarding the AWX, I have already sent you some data; as far as I know, the water temperature did not increase at all.

OK, thank you.

Quote:

IMHO: I doubt that a higher coolant flow rate will make much difference, because water can only "absorb" the engine heat within a certain time frame. What is more important is that the cooling surface area is sufficiently sized.

Hmm... but why does VW use larger fuel pumps in the ARL/BPX engines compared to the ASZ engines?
OK, I haven't been able to compare them yet, but what other reason could different pumps have, besides a higher water flow rate (as stated by Wendland, see above) with a higher Pmax?

Or could it be related to the fact that the ARL and BPX models have a front-mounted radiator and therefore receive warmer cooling air at high load (under the same external conditions) compared to the 130hp models with their wheel arch-mounted radiator?
A roughly estimated(!) figure of 8 kW of heat output from LLK heaters (i.e., 4 heaters at 2 kW each) before the water chiller is also something that should not be ignored...

ulf wrote:

...Or should it be related to the fact that ARL and BPX have a front-end LLK...?

Or simply by using a different type of hose connection and the resulting altered water connection, along with modified pump connections? But that's just an idea out of the blue.

Ulf,

Regarding the actual topic, I don't have much to say, but have you considered, instead, adding an additional oil cooler?

While the oil temperature reflects the increased water temperature with a slight delay, I personally trust the oil temperature more than the coolant temperature when it comes to controlling/reducing the heat balance of your engine.

These items are selling for around 100 euros on eBay, so it's also financially reasonable.

Best regards,

Obermeister wrote:

Have you ever considered, instead, something in the direction of an additional oil cooler?

Actually, no, because ASZ, ARL, and BPX already have the same oil-water heat exchanger .

I see it the same way you do, Ulf. I also believe that the primary purpose is to compensate for the reduced heat output caused by the upstream LLK (low-loss coils). However, it would be interesting to know how much higher the throughput is. Then we could calculate it quite precisely.

The cooling systems are preferably tested in Death Valley.
At 60 degrees Celsius or higher, especially when the air conditioning is running at full power.

I think we can easily reduce the water flow for each car's cooling system by half here, and it still wouldn't overheat under normal conditions.

It's highly unlikely that the cooling system is the limiting factor for a 20, 30, or 40% increase in performance.


If someone wants to haul a 2.5-ton caravan up a 2000-meter-high Alpine pass, things might look different... But in that case, I'd probably be more concerned about the oil temperature than the water temperature.