Am I the only one who has ever tried a K&N on a dyno? I read that ISO report and it just confirmed what I already know, keep a clean stock filter in your vehicle!

Dan

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81 240D 4speed with 300D engine
87 560SL
2005 E320
Yukon Denali
Sierra Denali
850 Turbo Volvo
1996 Mustang
1984 Mustang race car
3 Boats

DangerMouse:
Yes, I have an open mind and absorb all performance car info like sponge (a lot leaks out, but I try).
The theory is nice, but real life is different. The flow #'s are based on 1.5" of vacuum, a normally aspirated engine does not draw that much, so all those # are based on an error. The 1.5” number is used because it’s easy to work with for testing cfm, much easier than say 0.1”. Vacuum means there’s a restriction, restriction means power loss. If you’re running vacuum at full throttle then you need a bigger carb, efi, filter or whatever.
Btw, a well designed smog engine may have 80% efficiency, but not a performance motor. Not that 80-100% is a huge difference, but 1.5” vs 0.1” is.
I don't agree with your forced induction and heat theory btw, I didn't make sense. Not insulting you, just doesn't make sense.


89-300ce:
Yes, I do run a prefilter, but again it was difficult to find one that didn’t kill flow and power. Mesh and typical foam like those used for dirt bikes are too restrictive; once again I found the solution from K&N. The prefilter is open foam, the cells are huge and flow nicely. I use regular K&N oil, not foam filter oil. It’s really amazing how well K&N filter oil works, The prefilter can literally be backed in oily sand, yet the cotton filter is 99% clean. I can only guess the cotton filters out 99% or more of that remaining 1%. Oiled cotton can catch smaller particles than any dry paper filter, just like an old oil bath setup.

mctwin2kman:
You need to tune your car to run with the increased airflow of a K&N.
I have a K&N in my 190E too, but it runs fine either way.

On my 99 C280, the MAF died at 75K. No K&N. Stock air filter. The minute I told them the codes, the shop and Gilly said it was a MAF. Changed that and it went away till I totaled the car 10K later. On my Ford Ranger, I noticed a dead spot at WOT. Sprayed the MAF with some brake cleaner and it went away. On my 91 Firebird that was making 410HP at the wheels, I ran without any sort of piping in front of the TB and I was making 20HP more. Put a paper filter with the pipe and I lost 25 HP. That means that I am losing 5 HP between K&N and paper.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Chevota, I did change the mixture and all for the K&N. Just seems to breath better with the paper one, especially at higher engine loads such as when on the highway. I switch back and forth once in a while to test it out and the engine just seems to run smoother with the paper one than the K&N one. Personal opinion I guess. Really no diference in my mind. But I still have it in case I want to throw it in.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

Question: The tests are all wonderful. However, the truth of the matter is that even the best filter lets some matter thru. No engine runs on 100% pure air all day long. There is always something that gets thru the best filter because it is finer an item that will be filtered out. Just like a fishing net. Something will get thru. So, at what size does it become an issue to the engine?

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

It's not so much the size, but what it's made of. I imagine I could process small critters, or most food products all day no problem, but sand is a nightmare. Any dirtbike I've had have "baja bore" from riding in pure sand.

Chevota,

I am sorry to read that you still do not believe me. Your statements about volumetric efficiency and "all the #s are wrong" are wrong themselves.

The factory M119 is not a race-prepped engine where < 1in-hg vacuum at peak airflow is a desireable condition. The difference between full-throttle requirements at 1.5in-hg and (if it were possible) 0.1in-hg might be 10% at the top of the power band, much less with a realistic vacuum. Ask your favorite engine tuner if you do not believe me.

Regarding effects of intake air temperature and volumetric efficiency... not just another theory of mine. I get a sense that physics is just not your cup of Joe. Fair enough.

Here's what someone else has to say about it: http://www.procharger.com/intercooled.shtml

If you can stomach some real-world numbers:
The engines I built were pulling 55in-hg at peak boost (10psi) through a six-inch cone filter. Calculated peak airflow requirements using the formula were 436cfm at a 5500rpm engine speed, real-world measurements at the MAF were 407cfm. The formula does not take into account thermal inefficiency, but let's ignore that -- it is still within 7%. That is a reasonable margin of error.

I honestly believe you have a little knowledge about a technical subject, which can be a dangerous combination. No offense intended here. If you actually want to understand how to tune the internal combustion engine and induction systems, the following texts are a great primer:

Bosch Automotive Handbook (Bosch)
Advanced Engine Technology (Heisler)
Supercharged! (Bell)

Since this is pretty far off-topic, I am going to drop off this thread. Good discussion.

Regards,
-DM

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1995 E420 SE black/black
2004 Volvo V70R AWD

You make arrogant statements like that and then say you’re dropping the thread? You sound like my ex-wife.
Again your post has errors. Like most hot-rodders, they have some, but not all the understanding of what is really happening, the cfm rating is a perfect example. Good thing you have a blower to compensate. Do you understand why?

There is a huge difference between 1.5” & 0.1” of vacuum.
Is there a bigger difference between 0 and 1, or 1 and 3? Do you understand how this relates?

Do you realize you can’t compare cfm ratings of filters used on blower motors to those normally aspirated? Hint; this is basically the same answer as to why you can't compare the mfg cfm rating to real world normally aspirated motors.

Did you even read the information you suggested @ procharger.com? Do you even know why intercoolers exist?
You need to take remedial physics 101 if you think friction is where the heat comes from.

I doubt you’ll find all these answers in a book, so you'll need some above average mechanical inclination to re:.

The main problem with book smarts is if anything in the real world deviates from the book, you people don't know what to do. Another is books usually only contain enough data to answer the most common questions, which would explain your limited understanding?

Good luck...

I was just reading the April 5.0 and Fast Ford magazine and they dynoed a 05 Mustang GT with and without a K&N and the results were--------0, no hp increase!

Dan

__________________
81 240D 4speed with 300D engine
87 560SL
2005 E320
Yukon Denali
Sierra Denali
850 Turbo Volvo
1996 Mustang
1984 Mustang race car
3 Boats

" Results may vary by application ".
Maybe Ford finally learned a lesson re. aircleaner design?
Now, if they can just get rid of their restrictive exhaust systems.

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2007 C 230 Sport.