AFN Turbocharger Upgrade: Boost Performance

hi!!!!!!!!!
Okay, here's the translation:

'I have a question, maybe someone can help me. I have a Passat 35i, model year 1996, with a 110 hp TDI engine (AFN). I installed a power box for the fuel injection pump and also changed the resistor in the control unit to increase the turbo boost by 0.2 bar. The increase in turbo boost was noticeably better in terms of performance, and it doesn't produce as much smoke anymore. Is it possible to increase the turbo boost further without damaging the turbocharger? And if so, how would that affect the performance? It's now doing 212 km/h, compared to 200 km/h before. However, it's already reaching the redline. I have the feeling that the power drops off slightly at engine speeds above 4000 rpm, or am I mistaken? Thanks in advance for your answers.'
thank you, look chris

Hello,

If I were you, I would stick with the 1.2 bar boost pressure. With each further increase, your risk of experiencing bearing damage in the near future naturally increases. Ultimately, you have to decide how much risk you're willing to take.

Best regards, Rainer.

Hi,

212 km/h is quite fast for a Passat 35i with an AFN engine.
Enjoy it and leave everything as it is.

Regards,
arne

cz26m wrote:

Is it possible to increase the boost pressure further without damaging the turbocharger, and if so, how would that affect the performance?

Hi Chris,

You can further increase the pressure -> leading to charger damage, see Rainer's answer.

Performance-wise, I doubt anything else will come out -> Technical articles about LLK (liquid cooling) tuning.

hi
'Thanks for your replies. I'll leave it at 1.2 bar then. I'll also try adjusting the injection timing a bit. I'll try doing this via OBD2, let's see if it works. He seems to react to the accelerator pedal with a delay of about 1-1.5 seconds, or is that normal? I was hoping I could make him faster with simple adjustments, because I have no chance against a Golf 4 TDI with 150 hp, which was a bit frustrating.'
Sure, thanks in advance.
look, chris.

I guess that even with 150 horsepower, you won't stand a chance against a Golf IV with a 150 horsepower TDI engine. While a Golf IV is heavier than a Golf III, the Passat 35i is still a little heavier.

Best regards, WarLord.

Hi, I'm a new member starting today.
And here's a quick question to get us started.
'I have an A4 AFN, manufactured in 1999, with a KW turbocharger. It's producing a bit too much smoke, so I want to increase the boost pressure. Today, I logged the boost pressure values using VAG-Com, and the average was 1930 mbar. To me, that suggests I can safely increase the boost by 0.1-0.2 bar.'
and how do I find the 10k resistor exactly in my control unit? I opened it up today and immediately closed it again!
Best regards.

There was a thread about this here, which described it quite accurately. Also, it should be clear from the relevant scientific article!
Enjoy reading!

hi!

Okay, I've just copied an old email here. I hope it helps you.
look, chris.






hi
Okay, here's the translation:

'Here I am again. So, to explain: this is where you install the resistor. You'll find your control unit by looking into the engine compartment from the front, on the left side, towards the back, behind the rubber seal, under a plastic cover. It's usually a Bosch unit. It's located directly to the right of the air intake for the heater (on the Passat), and I don't know the exact location on other models. If you have an older control unit that's still partially encased in black plastic, you can skip the resistor modification. Since you have an AFN engine, I doubt that's the case. Before removing it, disconnect the battery. There's a small rubber hose connected to the control unit, which connects to the pressure sensor for the turbocharger (on the control unit). When you disconnect the large connector, you need to pull the lower, rectangular part of the connector to the left (towards the wider side of the connector), which can be difficult. This releases the locking mechanism, and then you can pull the connector off. Now, release the bracket holding the control unit, and you'll just have the control unit in your hand. Now you need a Torx 15 or 20 screwdriver to remove the four screws that hold the control unit in place. Be careful not to constantly touch the circuit board with your fingers; try to only touch the edges, as static electricity could potentially damage the ICs (although this is rare). Now you can see the pressure sensor (where the rubber hose was connected), which is a small, narrow box with a number on it. If the last two digits of the number are 210 (1.5 bar) or 211 (2.0 bar), then you can proceed with the modification; otherwise, it's not necessary. Now, look at the circuit board from the bottom; there's a plastic cover on it, but you can remove it (and it will go back on later). Look at the pressure sensor from the bottom; it has three small pins. Follow the middle pin, and you'll find the resistor. It's located almost at the edge of the circuit board, about 5cm away from the sensor. It's a surface-mount resistor, approximately 1.5mm in diameter and 4-5mm long, round, and with a few colored bands (brown-black-orange).'
'To eliminate it, apply the soldering iron for a while, heat it up, and gently push it. Then, carefully push it away. At around 18 kOhms, you'll see an increase of about 0.1 bar; 27 kOhms will result in approximately 0.2 bar more. You don't need an SMD resistor; you can use a regular one, for example, a 1/4 watt 27 kOhm resistor (from Conrad Elektronik). I also increased it by 0.2 bar about 10,000 km ago, and it's been running great so far. Make sure you don't damage the solder joints, bend the resistor beforehand, keep the resistor's legs as short as possible, and avoid creating any short circuits while soldering. Now, assemble everything, making sure the circuit board is properly seated during installation and when screwing it together.'
'I noticed the most power gain in the lower RPM range. The extra horsepower isn't as noticeable as with the auxiliary control unit. During an acceleration test on a track of equal length, I reached approximately 135 km/h with just the power box. After increasing the turbo boost and using the power box, I reached about 143 km/h, and the soot emissions decreased slightly. However, the car has a noticeably stronger initial acceleration.'
Let me know if it worked out. What kind of car do you have?
look, chris.

Hi,
Thank you for the response, but it doesn't help me, as I now know that I have an intake manifold sensor, but I already know what I need to do.
I have an A4 AFN model year 1999 with a box from KW .
Best regards,

hi
You wanted to know where to find the resistor, and I already described that. Or do you need any other information?
look, chris.






Examine the pressure sensor from underneath; it has three small solder pins. Follow the middle pin, and you will find the resistor. It is located almost at the edge of the circuit board, approximately 5cm away from the sensor. It is an SMD resistor, about 1.5mm in diameter and 4-5mm long, round in shape, and has a few colored bands (brown-black-orange).
Here's the translation:

'To remove it, apply the soldering iron for a while, heat it up, and gently push. Then, carefully push it away. At around 18 kOhms, you'll see an increase of about 0.1 bar; at 27 kOhms, it's about 0.2 bar more. You don't necessarily need an SMD resistor to replace it.'

@cz26m

'Whoever can read has a clear advantage!'




Now that I've found out that I have an intake manifold sensor.

@cz26m
There are various locations where the LDSensor can be found, such as in the engine control unit (ECU) or the intake manifold.
'In my case, it's located in the intake manifold, so I need to disconnect the pressure signal line and extend it with a resistor. According to reports, this resistor should be 10kΩ (for 110 mbar or higher).'
I have no idea what determines where the sensor is located.
Best regards.

'Hey everyone, I've been a very happy owner of an LDA (Linear Drive Assist) system since Saturday. It's already installed and running at a pressure of 1.2 bar. I also have a tuning box installed, and I can already say that I'm seeing at least 50% less soot.'
And now, a few questions:
I have a 1999 Audi A4 1.9 TDI with the AFN engine.
Pressure 1.2 bar, overpressure up to 1.5 bar: Is this normal or harmful?
I have a box, and it's claimed that the box doesn't increase the charging pressure, but according to my LDA, the box increases the charging pressure by 100 mbar. Is this true or false?
Less soot equals more power?
Best regards.