Airway Clearance: Objective Success Rates?

Hello,

Behind the exhaust outlet of the 6L Cupra FMIC (1.8T and TDI), the original equipment manufacturer (OEM) installed a somewhat oddly shaped plastic pipe that runs around a mounting guide for the front bumper.
Images of the pipe section: https://community.dieselschrauber.org/en/viewtopic.php?t=22000&start=16
and http://www.seatcupra.net/forums/showpost.php?p=3537371&postcount=107, on the right is always the entrance coming from the FMIC, and in the bottom picture, the part is upside down.
If you remove the aforementioned mounting guide, it creates space for a virtually straight pipe run from the front mount intercooler (FMIC) to the bend located behind the right headlight.
Forge offers something like that as a kit.
http://www.bar-tek-tuning.de/Forge+FMIBMAP+Seat+Ibiza+Druckrohr.htm
The LD sensor is located behind the headlight, so that the straightened airflow would not cause an increase in LD (Lean Definition) in the intake manifold (when the LDR is functioning correctly).

The intended (or suggested) effect of the Forge kit appears to be a reduction in air leakage between the turbocharger and the sensor: this would mean that the turbocharger needs to generate less pressure surplus to reach the desired pressure at the sensor. Consequently, less turbocharger drive power is required, the variable turbine geometry (VTG) or wastegate can be opened further, and the exhaust back pressure decreases.
Reduced exhaust back pressure, in turn, means fewer residual exhaust gases in the cylinders, creating more space for fresh air -> this should lead to an increase in air mass, even though the boost pressure remains the same.
However, a greater volume of fresh air entering the engine means a higher charging pressure, which in turn requires more energy extracted from the exhaust gases -> as a result, the back pressure doesn't decrease as much as one might initially expect.

Ultimately, any modification that increases the flow of fresh air without changing the boost pressure should result in an increase in the mass airflow.
In the Cupra forum, a driver of a 6L 1.8T is now reporting that, after installing the Forge kit, he couldn't see any significant before-and-after difference in his car's diagnostic data.
Given that the air mass measured in a turbocharged Otto engine is a fairly direct indicator of engine power, it seems likely that the alleged 7 horsepower increase mentioned in the second link is more of a marketing tactic than a reality. Achieving a +7 horsepower gain in the range of 200 horsepower would require an increase in air mass of approximately 3.5%, which, in my opinion, even the VCDS software should be able to show as a before-and-after difference... assuming the logs were taken with the same load and lambda (or air-fuel ratio).
It's conceivable that the environmental conditions during the logging process using the Forge-Kit were unfavorable, or that the gains were masked by noise in the diagnostic data.

Anyway, I'm considering straightening the air intake path on my modified BUK to reduce the load on the turbocharger, but that would only be possible if the Forge kit or a similar solution were more streamlined than the original air intake system.
I know: to determine this precisely, one would need to measure both parts using a flow bench (?), but I don't have that option.
Therefore, I would be interested in your opinions based on the images in the links. The OEM part, in a way, utilizes all the available space in height and width between the aforementioned front spoiler guide pin, the headlight, the front bumper crossmember, and the crossmember: Where there is little space in height, it expands in width, and vice versa. Consequently, its flow cross-section in the zigzag passage could be the same or even larger than that of the Forge kit in all areas.
Therefore, my question is:
What is your assessment of the likelihood that an air intake system designed in the style of Forge (even so) would be aerodynamically superior to the original equipment manufacturer (OEM) part?

ulf wrote:

. Therefore, my question is: How do you assess the probability that an air intake system designed like Forge (even so) would be aerodynamically better than the original equipment manufacturer (OEM) part?

As the only measure, I think that's nonsense. It's definitely not noticeably effective. And is that what you're aiming for, or are you only concerned with the measured values? If the intake and exhaust systems are so optimally designed and unrestricted, the software (SW) would need to be adjusted accordingly.

Quote:

It is definitely not noticeable.

I see it similarly. I think the key factor is the overall air resistance of the intake path. Whether and how much this can be reduced also depends on the constricting components, such as throttle valves, etc.

I believe that to achieve a noticeable improvement, the entire air intake path, from the cylinder head to the air filter, would need to be modified and shortened.

A single measure is likely to achieve little to nothing in relation to the effort involved.

Back in the good old days of the GTI, we used to modify everything from the cylinder head to the air filter. For example, the throttle body was always in the way.

BM wrote:

It is definitely not noticeable. Quote: I see it similarly. I think the overall resistance of the airflow is crucial. Whether and how much it can be reduced also depends on constricting components like throttle valves, etc. Constrictions and zigzag airflow paths fundamentally have a common "harmful" effect: a loss of pressure in the flowing gases, analogous to the voltage drop across an electrical resistor. Here, I suspect there's a way to reduce the overall resistance with minimal effort.

I believe that to achieve a noticeable improvement, the entire air intake path, from the cylinder head to the air filter, would need to be modified and shortened.

Quote:

It might be, but my focus here isn't on achieving performance gains that are noticeable on a dynamometer, but rather

simply on potentially reducing the load on the turbocharger, which – if it worked – would have to overcome slightly fewer flow resistances in order to provide the intended boost pressure behind the "restrictive" OEM component.
Without chip tuning, I wouldn't care, but with the tuning, I want to keep the additional strain as low as possible.

(Answers like "Then just turn it back, for example, 5 horsepower" are not ).

Quote:

...but only to potentially relieve the burden on the server, which -if it worked-

How many decimal places are we talking about? We don't really know. In my opinion, that's like doing work for free in your case.

If you really want to protect the battery, a more careful approach to using the accelerator pedal is probably the more effective way to do it.
It costs nothing, saves diesel and materials. Think about it.

BM wrote:

How many decimal places are we talking about? We don't really

know. . . Right. But maybe someone working in fluid dynamics will eventually provide an }estimate... ?

Ulf, quick question: What's the point of all the theory? Practice makes perfect! Often, doing something yourself helps more than just thinking about it!

Deus Violentia wrote:

Why all the theory all the time? Practice makes perfect!

Of course. But I'm not keen on crash landings, so I'd rather ask beforehand if someone can possibly predict the outcome.

However, despite my best efforts, I think that sometimes the outcome is difficult to predict.

ulf wrote:

Constrictions and zigzag-shaped air passages generally have a common "harmful" effect: a loss of pressure in the flowing gases, analogous to the voltage drop across an electrical resistor.

That's correct, but resistance could certainly have been deliberately introduced into this chain.
I shudder to think about the ballast resistors for various ignition coils. Remove those resistors, and the coils will fail much faster than you'd like. But in the short term, the engine would have had a lot more power.

Quote:

It might be, but here, I'm not concerned with performance gains that are noticeable on a "popometer" (dyno), but rather only about a possible reduction in the load on the charger, which - if it worked - would have to overcome slightly fewer drag forces in order to provide the intended charging current behind the "restrictive" OEM component. Without chip tuning, I wouldn't care, but with the tuning, I want to keep the additional strain as low as possible.

I can understand that, but this modification will only bring money into the seller's pockets. It definitely won't make your turbo last noticeably longer. In fact, the price-performance ratio is likely to be extremely poor.

Quote:

(Answers like "Then just turn it back down, for example, by 5 horsepower" are not )

.

Okay... Then I'll skip that...


Do you know my AXR? It just reached 205,000 km.
Everything else has already crumbled, but the turbo has held up despite the tuning (and still does). I'm largely indifferent to such a "crash landing" because I have the corresponding spare parts. Nevertheless, I don't worry about it much.

Bertil wrote:

This modification only brings money into the seller's coffers. It will definitely not make your turbo last noticeably longer. At the very least, the price-performance ratio is extremely bad.

Ah, Bertil is the first to give an estimate that answers my question -> thank you.

I once tried to determine the order of magnitude of the pressure loss in the plastic pipe section after it had been deformed, at the maximum pressure (Pmax).

http://www.druckverlust.de/Online-Rechner/index.html
When appropriate flow data is entered and a 180° pipe bend with an inner diameter of 45 mm and a bending radius of 50 mm is selected (assumed to be a flow-equivalent substitute for the plastic pipe section), the results show a pressure loss of less than 5 mbar.

A straight 55 mm pipe section, 50 cm in length (a replacement model for the Forge part), has approximately 2-3 mbar less pressure loss.

For quantities of this size, it really doesn't make sense to change anything about that plastic pipe component...

"By chance, I came across a modified intake manifold from a 151 hp AHY engine for my R5 TDI."
I hadn't expected to see any noticeable improvement in performance, but I was proven wrong...
"It noticeably had more power and a more even power delivery... not a lot, but it was noticeable."
"However, the AGR (Abgasrückführung - exhaust gas recirculation) system was completely removed (previously, the stupid rod to the vacuum pump was in the way), and a sharp 90-degree bend was also removed."
It should be mentioned that I'm running at 2.0 bar... which is a completely different scale.
It would be much more interesting to further reduce the LLT (Lower Landing Threshold).
I also used to have 2 LDA implants.
1x before and 1x after the liquid cooling system... with good cooling, you have a pressure difference of about 10% starting from 1.5 bar.
I've also already done vacuum measurements before the turbocharger, and by optimizing and increasing the vacuum, I was able to reduce it by up to 100 mbar.
Depending on where you want to go, the total amount of optimization can make a difference.
But I would never do that just to ease the burden on a driver...

"So, I recently received a collection of before-and-after logs from a Cupra TDI driver, who was hoping to see improvements thanks to the tuning pipe. Most of the logs were recorded on the same day, before and after the modification, so the environmental conditions were practically identical."
Unfortunately, nothing can be derived from the MWB10 data because the WOT boost pressure is only occasionally regulated in a somewhat appropriate manner (which, in my opinion, is not entirely the fault of its tuning software), but otherwise, the lambda value is too low, and the oxygen sensor is usually at the limit of the diagnostic scale -> therefore, it is not possible to calculate a realistic relationship between lambda and boost pressure that could be used as a general statement about the permeability of the intake passages.

In at least two MWB11 logs (with the serial and tuning pipes), the boost pressure control is working "well enough" that the target boost pressure isn't hitting its maximum limit.
My expectation of changed values if the tuning pipe were to provide a sufficiently significant improvement:
Here's the translation:

"Since the LD sensor is located behind the removed restriction, the turbocharger needs to produce less pressure surplus to compensate for the pressure loss up to the sensor. This would result in a less aggressive turbocharger control, which would manifest as a wider opening of the VTG (wastegate) compared to using the stock pipe."
2. Since the input tax credit (VAT) calculation is no longer accurate, there may be a tendency to observe higher actual load (LD) values.

However, the two evaluable logs show exactly the opposite when compared.
The regulated LD setpoint trajectory is slightly lower with the tuning pipe, but in my experience, this also occurs within the range of real process variations when using multiple logs with identical hardware.
The tuning pipe adjusts the turbocharger slightly more aggressively (by closing the VTG further), but in my opinion, this is simply the control system's logical response to the lower turbocharger pressure curve.

Overall, the two logs that can be analyzed do not show any "measurable" effect of the tuning pipe according to VCDS.