TDI Intercooler Upgrade for Audi Cabrio MKB:AHU

Hello everyone,
I would like to install the performance-enhanced version (chip upgrade from 90 -> 115 hp) in my convertible. I have already done this by swapping the engine control unit, but only for comparison tests. While driving on the highway, I recorded the boost pressure and charge air temperature using VAG-COM. At an ambient temperature of 25 degrees Celsius and a boost pressure of 0.9 - 1.0 bar, I measured a charge air temperature of 70-72 degrees Celsius.
The air intake (org. LLK) is very small and located discreetly (under the right wheel, under a support with dimensions 245mm x 100mm x 80mm), and the airflow is further restricted by the tow hook. The question is: what to do?

It's impossible to mount a larger one in the original location; placing a new one in the front of the vehicle is difficult due to brackets and obstructed airflow! But who would even do something like that?! And where/who could approve such a modification?

What should I do? / What can I do?
What is meaningful?

Regards,
TDI-Schorsch

You can take the wheel well from an RS4, cut out the grid, and "weld" it into your own wheel well. This allows air coming from the front to directly flow through the intercooler and escape towards the rear.

Hi Schorsch,

Are you really almost 50 Kelvin above the outside temperature?

My Golf 3 with the 1Z engine never exceeded a "normal" speed of 30 km/h. However, after various modifications and with approximately 120-130 horsepower, I've never actually measured its top speed.

I might need to get one eventually, though, since my friend is still using his regularly.

Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

Hello cksIT,
I had also read about venting towards the wheel arch in the Audi Cabriolet forum before, but that post is no longer available, and there were no measurements included. Someone here in the forum tried something similar - they drilled some holes in the wheel well of an A3 and measured the temperatures. However, the temperatures were always around 50 degrees Celsius, whether or not the holes were present.
I was thinking of enlarging the air intake, but the tow hook and crossbeam are in the way, so only about half of the bumper cutout can actually be used.

Hello Dieselmartin,
The values actually match what was logged using VAG-COM. With software from Digi-Tec, at full throttle on the highway, with a boost pressure (LD) of approximately 0.9 - 1.0 bar, the measured value was 70 degrees.

After removing the cover from under the car yesterday, I have to say that there is almost no space for a larger front-mounted intercooler in that location, and furthermore, the incoming air flow wouldn't be improved.

Regards,
George.

Could you please log a 003-008-011 and something with 007?

I believe everything you're saying, but it sounds pretty intense to me.

greetings
Okay, please provide the German text you would like me to translate into English. I will only provide the translation.

TDI-Schorsch wrote:

Since the org. LLK is very discreetly integrated (located under the right wheel, beneath a support with dimensions BxHxT of 245mm x 100mm x 80mm), and the airflow is further restricted by the tow hook, the question is: what to do? ???????

Hi,

Part 2 follows.
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.
Read through everything and try to optimize the cooling air flow .

Where is the MAP sensor located in your car? Is it in the intercooler or in the intake manifold between the intercooler and the engine?

I had also read about the issue with venting towards the wheel arch in the Audi Cabriolet forum before, but that post is no longer available, and there were no measurements included either.

Hello everyone,

Is the post no longer available?
That was mine!!
At that time, I hadn't yet used VAG-COM, so there are no temperature logs available.


The values actually match what was logged with VAG-COM. With software from Digi-Tec, full throttle on the highway, and a boost pressure (LD) of approximately 0.9 - 1.0 bar, the measured value was 70 degrees.

I also had mine tuned using the same software. Here's what I got: 123 horsepower and 304 Nm of torque...
Since my tuning is limited by the mass airflow sensor (which restricts smoke), it's possible that my intake air temperature is lower than usual. Additionally, the entire intake system has been modified. The software is based on the tuner's standard settings and should theoretically produce 115 horsepower.
My maximum boost pressure is around 1.05 bar.

I've also been considering a larger intercooler. Due to space constraints, I initially thought about a dual intercooler system where two standard intercoolers would be connected in series.
However, since the success did not justify the costs, the project was abandoned.

Now I only use the convertible for cruising and rarely need to drive at the maximum legal speed for long distances.

Best regards, Jochen.

Hello dieselmartin,
I'm going to log those values right away.
Can I post this here or send it via private message?

Hello Ulf,
I've already read the report. The section about restricting the intake path, specifically the discussion of turbulence and the potential for incorrect readings from the lambda sensor, was a bit confusing to me. Also, the air inlet to the air filter box in the headlight housing seems rather small.
The charge air temperature sensor is located between the intercooler (IC) and the intake manifold, specifically behind the IC in the center of the airflow path. As far as I can tell, the charge pressure sensor is integrated into the engine control unit (ECU), and the pressure hose connects to the back of the intercooler – which means it's likely a 1.5-2 meter long plastic hose.

Hello Jochen,
Could you please provide the link to that post? Maybe I'm just too clueless to find it myself.
Where exactly were you planning to install the two LLK units? There's hardly any space there, not to mention the risk of losing the operating permit!!! I had also considered it, but I would prefer to install them in the front. With a bit of luck, there might be space for something around 500mm x 180mm x 50-60mm, and you could still manage the hoses – they'd just be about 1 meter longer. The space is very limited due to the air conditioning condenser.
Regards,
George.

TDI-Schorsch wrote:

Hello dieselmartin, I'm going to log those values right away. Can I post it here or via private message ??????

For that, we have this upload forum.
In your case, I would log MWB values 7, 8, and 10 simultaneously: they contain everything that is currently important (except for the speed, but you can briefly describe that as a driving profile).

Quote:

The charge air temperature sensor is located between the intercooler (IC) and the intake manifold, so behind the IC in the center of the airflow path. As far as I can see, the charge air pressure sensor is located in the engine control unit (ECU), and the pressure line is connected behind the IC - that's probably a 1.5-2 meter long plastic hose.

Wow, the difference between the lower limit of control (LLC) and the motor is almost 50k above the auto-tuning (AT) point at 1 bar. That's a really bad value...

The thin, long tube to the LD sensor is not problematic because no volumetric flows occur there that could create a pressure drop (which would distort the measurement).

the post???? do you have another link, maybe I'm just too stupid to search and find it
No, I can't find the post anymore either. It used to be located under the 'Diesel Technology' section. Apparently, that topic has been completely removed.
Only my brake report is currently available online.
If I ever feel like I'm back in my old environment, I should try starting up my ancient computers; the post might still be found there as a *.doc file.
Where did you want to build the two LLKs?
The idea was to install a second series of liquid cooling lines on the left side, where the horns are located.
It must be assembled in a mirrored configuration.


There's no room for that, not to mention the risk of losing the operating license???!!!

Yes, that's how it would have been, just like with almost all unauthorized modifications to the vehicle. There are only a few exceptions, and you really need to know exactly what they are.
(like an underbody protection, whose diffuser function was actually not intended and surprisingly emerged =

Best regards, Jochen.

Hello Ulf,
Hello Dieselmartin.
Hello Jochen,

I recorded the logs this afternoon and uploaded them here.
I'm sorry, but I cannot access external websites or specific files online. Therefore, I am unable to translate the text from the provided URL.


The outside temperature was 11.5 - 13.0 degrees Celsius according to the external temperature display.
The speed was approximately between 160-170-180 km/h.
The edges of the road were still wet, while the lane markings were dry.
Based on what I could see, the low-temperature limit (LLT) is now just above 50 degrees. The old log data at 25 degrees and an LLT of 70 degrees is unfortunately unavailable.

However, I noticed that the actual and target air mass values were around 850 when the engine was running at full throttle.

Regards,
George.