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K&N Air Filter: Explained & Reviewed

 
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Bertil
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Post17-03-2004, 15:12    Subject: K&N Air Filter: Explained & Reviewed Quote

Hi,

[Link]

Quote:
A positive side effect, due to the increased airflow, is a noticeable performance gain, which naturally varies from engine to engine.


Increased airflow? ... Well, Rainer's test showed the opposite.

Quote:

In turbo engines, or more specifically, in small-scale turbines, a crucial advantage of the K&N filter is that the turbine speed can be significantly reduced, which in turn can increase the lifespan of the turbocharger.


Reduced turbine speed? And at the same time, a higher airflow rate? I can't really explain that. icon_rolleyes.gif
Gruß Bertil

Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX

*** Technische Anfragen per PN werden von mir nicht beantwortet! ***


Translated on 01-10-2026, 13:00.
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garth.brooks
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Post17-03-2004, 16:18    Subject: Bertil: More Creativity, Please! Quote

Hi Bertil,

Come on, use a little more imagination!

If, due to subatomic charge effects, particularly incorporating the latest hyperspace laws (Star Trek, third season), the air pressure before the turbocharger inexplicably doubles (from a layman's perspective), then the density increases, which in turn reduces the turbocharger's speed while simultaneously increasing the air mass flow rate.

Is that a logo or what? icon_lol.gif


Translated on 01-10-2026, 13:05.
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Julian
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Post17-03-2004, 19:39    Subject: K&N Air Filter: Explained & Reviewed Quote

Sorry, Bertil, but what kind of cheap tuning website did you find?

Reference is to the manufacturer:

http://www.knfilters.com/filtercharger.htm


Translated on 01-10-2026, 13:07.
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Bertil
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Post17-03-2004, 20:17    Subject: More Imagination Needed: A Response to Bertil Quote

garth.brooks wrote:
Hi Bertil,

Come on, use a little more imagination!

If, due to subatomic charge effects, particularly incorporating the latest hyperspace laws (Star Trek, third season), the air pressure before the turbocharger inexplicably doubles (from a layman's perspective), then the density increases, which in turn reduces the turbocharger's speed while simultaneously increasing the air mass flow rate.

Is that a logo or what? icon_lol.gif



ÄÄÄÄÄHM, ahh yes... now we're talking about Rohrbroch... and what is the influence of the relative lunar humidity??? icon_question.gif


Julian wrote:
Sorry, Bertil, but what kind of cheap tuning website did you find? That's not the kind of research I expected from you, given your professional background.


icon_redface.gif icon_redface.gif icon_redface.gif I received the brochure when I bought my AXR from my dealer. While cleaning up, I found it again, and I was curious, so I opened the page (with no ulterior motives -- honestly). After reading it, I quickly closed the browser.
I didn't want to withhold this "highlight" from you. icon_biggrin.gif
Gruß Bertil

Skoda 5E5 CZDA + Mini R50 W10 + VW ID.3 + Fiat Ducato 250 + 161 DX

*** Technische Anfragen per PN werden von mir nicht beantwortet! ***


Translated on 01-10-2026, 13:12.
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joergs
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Post17-03-2004, 20:25    Subject: K&N Air Filter: Explained & Reviewed Quote

My browser stubbornly refuses to open this page. Is it due to the antinox milies or the acceleration of the counter-metaseed??? icon_cool.gif


Translated on 01-10-2026, 13:15.
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felix
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Post18-03-2004, 18:17    Subject: K&N Air Filter: Explained & Reviewed Quote

Bertil wrote:
Larger airflow? .... Well, Rainer's test showed the opposite.


Regarding Rainer's test, I would like to point out that its evidentiary value is rather low.
Our TDI engines have a turbocharger and thus an air intake control system that will certainly compensate for minor differences in air filter resistance.
A proof would be if a vacuum cleaner with full, unregulated power were to suck on the air filter, rather than a controlled TDI engine.
Gruß Felix
E91 330d, 1/2009


Translated on 01-10-2026, 13:17.
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Gremlin
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Post18-03-2004, 21:40    Subject: K&N Air Filter: Explained & Reviewed Quote

Yes, but that's exactly what it's about icon_wink.gif.

because it is stated everywhere that with turbo engines, you MUST install a K&N filter due to the performance increase icon_wink.gif.

Man, I'm annoyed that I didn't open a shop like this years ago...

@bertil

A good filter logically reduces the turbocharger's speed. Just think about what the turbocharger (or its boost pressure control) does when there's a blockage in the intake pipe...
and again, it bothers me (see above), because these vehicles of this caliber will probably also need new mass airflow sensors (MAF sensors) every 50,000 km, because the old ones are getting oiled }.

'By the way, I experimented with a differential pressure sensor on the airbox for a while. I compared a new filter to an old one (35,000 km). There was absolutely no difference, even though the old filter was visibly dirty (~6 mbar at 4300 rpm full load). I replaced it around 40,000 km. There was no noticeable difference in driving or engine performance. This is because the 'air resistance' of the filter increases exponentially. Everything is fine until about 70% load, but then it increases very rapidly...'


CU Gremlin.


Translated on 01-10-2026, 13:19.
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felix
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Post18-03-2004, 22:12    Subject: K&N Air Filter: Explained & Reviewed Quote

I certainly didn't want to break anyone's lance for those oil-soaked creatures. icon_wink.gif
Gruß Felix
E91 330d, 1/2009


Translated on 01-10-2026, 13:21.
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