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Is it K&N Air Filters bad for MAF?

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Old 12-19-2008 | 12:38 AM
  #16  
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I use BMC filter and sportec intake....got rid of the V-blow as it blew MAFs like a cheap hooker blows....The BMC is oiled, but I washed it before using....it has not had any problems as far as MAFs go.

It is almost impossible to dyno test the intake as there is no normal air flow....I suppose some runs would provide some data.
Old 12-19-2008 | 01:28 AM
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Originally Posted by Abakar
ok is proven we have the MAF issue. But it is a fack that the turbos breath better with the K&N oviuos is less restricted than factory air filter so less effort. Then why is no HP gain?

What is this "breathe better"??? (It is also not a 'fact') If you view a motor as a 'fuel powered air pump' then you come to understand that anything that restricts air flow will reduce power- BUT, opening up one area will not increase power unless the entire path can utilize that increased flow.

This means that removing an air filter only helps if the rest of the motor can 'use' the increased flow...if the air filter wasn't the restricting item to begin with, a 'higher flow' filter does nothing.

This is why people generally say under 600HP you can stay with the stock filter.

But go to bigger turbos, bigger intercoolers, larger injectors/fueling system, flash, etc... and then you are in a situation where maybe you can't use paper and a foam or other sub 99% efficiency material is needed.
Old 12-19-2008 | 08:30 PM
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I have a 944 turbo and the minute I replaced the air filter for the High Flow MAF intake from Lindsey Racing the diference was enormous. Later I changed all of that (intercooler, turbo, pipes, etc) and the car kept gaining HP.
As I learned 996tt is a different thing and making it gain HP the procedure is differs from any other mortal engine. So, changing for a K&N and replacing the pipes for 75mm from Protomotive i should have a HP increase.
Old 12-19-2008 | 08:34 PM
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"breathe better" i ment that they can suck easier the air cause is less restricted. But as you said then to inyect the air to the engine is restricted it wont do any difference.
Old 12-19-2008 | 08:58 PM
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I replaced the air filter for the High Flow MAF intake from Lindsey Racing
It's not apples to apples, you replaced the entire MAF assy and housing in your 951. To keep things correct keeping the stock flapper air sensor, and factory air cleaner assy, and just installing a K&N>>would equal this application.

At this point run the K&N, it's not worth losing sleep over. Life is too short. If you eat your MAF sensor you can buy another one.
Old 12-20-2008 | 11:08 AM
  #21  
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Originally Posted by wross996tt
I use BMC filter and sportec intake....got rid of the V-blow as it blew MAFs like a cheap hooker blows....The BMC is oiled, but I washed it before using....it has not had any problems as far as MAFs go.

It is almost impossible to dyno test the intake as there is no normal air flow....I suppose some runs would provide some data.

what is the difference between your BMC and the K&N ?

if i wash it and be very careful with the procedure to clean it what is the problem ?
Old 12-20-2008 | 11:48 AM
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Originally Posted by Alex_55
what is the difference between your BMC and the K&N ?

if i wash it and be very careful with the procedure to clean it what is the problem ?
No idea...I just followed my tuner's recommendation (actually got the filter included with the intake) and cleaning procedure. I have no data, but it seems the only filter I hear complaints about is the K&N. As I said, no problems with mine! and I love the red trim...LOL.
Old 12-20-2008 | 09:25 PM
  #23  
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Nice engine Statman. I saw that air intake but my question, do you to have cut the plastic in the lid to fit the other intake?
Old 12-21-2008 | 11:58 AM
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Originally Posted by Abakar
Nice engine Statman. I saw that air intake but my question, do you to have cut the plastic in the lid to fit the other intake?
I bought a second "bracket" (as the part is called) and yes I did cut it to match the snorkel. This is how you get more cold air to the intake.
Old 12-21-2008 | 01:37 PM
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The only reason the K&N is more efficient on airflow is the lack of filtering by the media itself. That's why you have to oil it...to trap the particulates. No matter what you do, the air velocity across the K&N is going to wick the oil out of the media and down the pipe eventually rendering your filtering efficiency to the level of a bug screen.

As far as the stock setup goes, to maintain a minimum pressure drop across the filter, the stock media is folded in such a way as to extend the total surface area to a point where it fits the plenum and does not excessively restrict flow. The stock filter media could be more efficient on flow if it were re sized to include deeper pleats, increasing the total surface area and a greater reduction in differential pressure. Unfortunately this could crowd the stock plenum and restrict flow resulting in a diminished return. This is probably why the enGuneers at Stuttgart went with the current balance of components within the stock box.

Besides, if oiled media were efficient in trapping harmful particulates, then I'd be shoving them in Cleanroom ceiling systems rather than those silly HEPAs.

My $0.02
Old 12-21-2008 | 02:24 PM
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Originally Posted by drh
The only reason the K&N is more efficient on airflow is the lack of filtering by the media itself. That's why you have to oil it...to trap the particulates. No matter what you do, the air velocity across the K&N is going to wick the oil out of the media and down the pipe eventually rendering your filtering efficiency to the level of a bug screen.

As far as the stock setup goes, to maintain a minimum pressure drop across the filter, the stock media is folded in such a way as to extend the total surface area to a point where it fits the plenum and does not excessively restrict flow. The stock filter media could be more efficient on flow if it were re sized to include deeper pleats, increasing the total surface area and a greater reduction in differential pressure. Unfortunately this could crowd the stock plenum and restrict flow resulting in a diminished return. This is probably why the enGuneers at Stuttgart went with the current balance of components within the stock box.

Besides, if oiled media were efficient in trapping harmful particulates, then I'd be shoving them in Cleanroom ceiling systems rather than those silly HEPAs.

My $0.02
I alluded to this above.... the discussions on 'aftermarket air intakes' focuses on HP gain, performance gain, dyno results.... and specifically omits any real discussion of particulate filtration or efficiency. After all, it isn't sexy and you can't SEE it.

If the discussion was, up front, "I know this filter lets more dirt in but that is an OK trade off for a few HP" it would be a rational discussion....

Personally I think the engineers at Stuttgart have access to ISO5011 test data and based their decision on that.

A
Old 12-21-2008 | 02:49 PM
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Just backin' you up Adam. That's why I only added $0.02 to your $0.10
Old 12-21-2008 | 07:40 PM
  #28  
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Originally Posted by drh
Just backin' you up Adam. That's why I only added $0.02 to your $0.10

We're up to 12 cents... pretty soon we can afford a new intake!

wross- looks great and I like the fact that it maintains the very large filtration area.

PS You cleanroom/HEPA caused me to think "Hey. lets make an electrostatic intake filter...there is enough science and truth around that it'll be easy to fool a bunch of people and make some money!"
Old 12-21-2008 | 09:06 PM
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While were at it, let's loop the A/C over and refrigerate the intercooler. Should be good for about 50hp if we dry lab the numbers.



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