Suction pipe throttling

Hello.
After studying the article about removing the throttle restriction in the intake manifold, I have a question: Can I feel or measure any improvement without actually measuring the vacuum pressure inside the air filter housing?
Could the boost control valve be controlled with a different frequency? Because if I save a few millibars in the vacuum range, the turbocharger doesn't have to compensate for that smaller difference between the intake and exhaust sides, which means it needs less speed. Do you even notice that?

I'm going to start experimenting with my convertible. !!!
The intake manifold actually only has a diameter of 40mm, which is just 12.5 square centimeters – that's really small.
The intake manifold from a 2.8E engine that I believe is suitable has a diameter of 55mm, which equates to approximately 20 square centimeters, or 1.5 times the size. This should be enough to notice a difference.

What do the experts say?
Should I go with a 70mm diameter intake manifold (like the one from the S2 with its original 230 hp), which would result in an area of approximately 38-39 cm², or about three times the current area?

I'm looking forward to hearing your opinions.

Regards,
George.

TDI-Schorsch wrote:

Can I feel/measure a success without actually measuring the vacuum pressure in the air filter housing??? Perhaps the boost pressure control valve will then be controlled with a different clock rate ???

Theoretically, yes. In practice, it naturally depends on the pressure increase in the air filter housing. Additionally, the charging curve of the turbocharger varies slightly each time during acceleration, even when the exact same driving profile is followed under the same environmental conditions.
Therefore, the success could only be precisely determined by comparing the average results from multiple runs, each with the series intake manifold and a de-restricted intake manifold.

Quote:

because if I save a few millibars in the suction area, the turbocharger doesn't have to bridge/increase that smaller difference between the suction and pressure sides, which means the turbocharger needs less speed -------do you even notice that????

Probably not on the dynamometer, but yes, statistically speaking, regarding the lifespan of the turbocharger, because it runs at a lower overall speed under full load.

Quote:

The intake manifold, which I believe is suitable for the 2.8E engine, has a diameter of 55mm, which equals approximately 20cm², or 1.5 times the size - This should already be enough to notice a difference. Should I go with a 70mm diameter (intake manifold from the S2 with original 230 HP), which would be about 38-39 cm², or roughly three times the area?

Predictions are difficult in this case, but I would start with the S2 pipe to initially experience the largest possible effect. }

Hello Ulf,
danke für deine Einschätzung. Der Lufikasten des S2 MKB:ABY sollte unter das Lufikasten Oberteil meines TDI passen allerdings schwer zubekommen. Wie ich jetzt heraus finden konnte gibt es sogar noch einen Steigerung im gleichen Lufikasten -> RS2 org. 315 PS Saugrüsselöffnung von 100mm = 78,5cm² also nochmal verdoppelt. Der ist zwar fast garnicht zubekommen und die Ansauggeräusche saugen warscheinlich ganze Dackel vom Gehweg. Wenn die seitlichen Klammern da passen, denn es soll ja aussehen wie original, dann werde ich wohl mit dem S2 beginnen. And I was surprised by the background noise.

Regards,
George.


PS: The air intake area for the turbocharger can be increased by a factor of approximately 1.75 in the TDI convertible. Further improvements are possible using a hot air blower.

(..)und die Ansauggeräusche saugen warscheinlich ganze Dackel vom Gehweg.

Hello Georg,

'In this area as well, I modified my air intake system. I removed the original 'trumpets' and replaced them with a custom-made pipe that has a corresponding cross-section (the mounting point is significantly larger than the actual air inlet opening). The cover behind the headlights also needs to be adjusted accordingly. The cost is almost zero, but it took an afternoon of work.'
The change in the cross-sectional area and the narrowing of the intake piece in the filter have significantly altered the suction noise.
It has become deeper and louder...

I don't know if the response time has changed, but it definitely sounds faster .

The increase in the air intake cross-section for the turbocharger can be further increased on the convertible TDI to approximately 1.75 times its original size. With a heat gun, it might be possible to achieve even more.

Then adjust the ventilation behind the liquid cooling system, and the foundation for a suitable low-temperature coolant (LLT) is established.

Best regards, Jochen.

Hello Jochen,
By shortening the tube in the air filter housing, the airflow to the mass airflow sensor has also changed. Have you noticed any negative effects from this?
What size and type of pipe did you install, including its diameter and length?


Regarding the intercooler: I think I'll know more after the Essen motor show; perhaps there's a tuner who can arrange for the installation of a different intercooler in the vehicle's front ----> if it doesn't cost a fortune but helps the engine run cooler. Until then, it will probably still be winter, so it will be colder outside, and then I'll decide whether to open the wheel arches.

Regards,
George.

Sure, here is the translation of the text from German to English:

'PS: If you could find out the dimensions of the intake manifold, that would be great.'

By shortening the tube in the air filter housing, the airflow to the mass airflow sensor has also changed. Have you noticed any negative effects related to that?


No, I couldn't.
Before the tuning, a power measurement was performed. The engine showed surprisingly good results: it produced 100 horsepower. However, the torque was rather average: 220 Nm.

I would have initially assumed that the changes to the intake manifold and intercooler were responsible. However, I now understand how the standard software works. It rigidly limits power through torque limiting, so the increased performance couldn't have come from those modifications alone.
However, the tuning goes beyond just reducing emissions, and we achieved impressive results of 123 hp and 305 Nm using a customer-provided base file, even though we were expecting around 115 hp and 280 Nm. This likely indicates that the modifications have had a significant impact.
But as I said, the software now works differently.

If you could find out the dimensions of the intake manifold, that would be great.
If I could finally find the time to take the vehicle for its technical inspection (TÜV), I would also be able to finally conduct some test drives.
Currently, my convertible is having a flat tire.

If I'm near the car again soon, I'll take some pictures.

Best regards, Jochen.