Some Interesting tips from the K&N catalogService Interval Tips
K&N Filtercharger service interval is dependent of usage, obviously the
dirtier the environment in which it is used in, the shorter the interval.
K&N recommends the proper way to determine when their air-filter needs
service is by the use of an air restriction gauge. This gauge measures the
pressure differential between the inside and the outside of the filter. The
maximum allowable restriction for a K&N Filtercharger is 15-inch if vacuum
(water). If the restriction is allowed to go higher, the filter media might
become so restricted that the element could distort and allow dirty air to
bypass the filter and enter the engine. On the other hand, cleaning the filter
too often will shorten the serviceable life expectancy.Service
A K&N Filtercharger can be washed up to 25 times before it is considered
as no longer serviceable (and must be replaced). K&N recommends replacement
after 25 washings even if the filter shows no outward signs of deterioration.
Excessive washings will actually deplete the tiny cotton hairs that crisscross
the openings, the resulting damage allowing the smaller dust particles to pass
through.Oiling and Over-Oiling
When servicing a K&N filter, it is important not to over-oil the element.
Doing this will impede air-flow and the excess oil can also migrate into the
intake system where it can coat electronic sensors and affect their operation.
Thus K&N warns to never saturate the filter - if oil drips from the filter,
it should be washed and re-oiled again. Only K&N oil should be used. The
safest method would be to always follow the oiling instructions included with
Types of K&N Filters
There are three main types of K&N Filterchargers for street use that
applies to Hondas. These are 1. Stock Replacement Air Filter, 2. Fuel Injection
Performance Kits (FIPK) and 3. Universal Air Filters. We will examine all three
Stock Replacement Filters
These are exact replicas of the stock OEM paper filters but made
by K&N using their unique technologies as described above. In
the catalog, K&N stated some generalized gains from usage of
these replacement filters, including the ability to have up to 1/8
inch of dust covering the Filtercharger before performance is
significantly affected, the ability to last up to 50,000 miles
(80,000 km) before service is required, and the ability to double
air flow which in turn can add up to 15 extra hp.
Obviously this does not apply to all situations.
Do NOT expect to gain 15 hp from the use of any aftermarket
air-filter systems on Honda as a general rule
There is a unique K&N Filtercharger replacement element for all
Honda models that they cover and in the catalog, there are almost 120
pages that lists all K&N Filterchargers made, Honda models covered
will include all variants that have been marketed in the United States.
Obviously JDM and non-US models will not be listed. However I was using a K&N in my previous Malaysian market
EF-Civic 1.6EX which uses a 1590cc SOHC dual Keihin carb'ed engine and the
K&N Filtercharger I got was listed as for the 1.4l dual-carb'ed
European model so it would seem K&N do make Filterchargers for non-US
models, perhaps in their manufacturing facilities outside of the
There is also a Honda OEM filter part-number to K&N Filtercharger
model number cross reference in the catalog and this cross reference table
would probably be more useful to owners of JDM and non-US spec Hondas. The
table is reproduced on the right but at any time, K&N should still be
consulted for the latest correct cross-reference list.
The strength of K&N Filtercharger replacement filters is that they
can be directly installed in place of the original filter. No fitting of
any form is required and because they work with the stock air-intake
system, enjoys almost the same low noise level as the stock OEM filters
but with higher air-flow and longer service interval
FIPK on the
Fuel Injection Performance Kits or FIPK for short are the famous
K&N open-element cone type filters. Designed to be used with
fuel-injected engines, FIPK replaces part of the stock air-intake system,
typically the air-box that contains the filter element. Installation of
FIPK will require some fitting and mounting work; first the stock air-box
will have to be dismantled and removed from the engine bay, then the FIPK
kit will have to be installed in its place.
In most cases, the FIPK will contain all the parts needed to make the
filter work, including (if necessary) a pipe to insert into the stock
intake hose so that the K&N cone element can be placed in the area
where the stock air box used to be.
In the catalog, the K&N FIPK Design Concept is explained as being
to promote performance in fuel-injected stock engines by creating air
filtration with the least resistance in air-flow. FIPK's have specially
designed filters with woven cotton fabric pressed between 2 layers of wire
mesh screen (ie the element design described above). The screen and fabric
combination is said to create a grid-like effect which actually
straightens out the incoming air as it passes through the filter. FIPK's
also have uniquely designed adapters that act like a built-in velocity
stack. A velocity stack is a specially designed tube
that has varying diameter, typically larger at the mouth and gradually
tapering smaller. This design is supposed to increase the velocity of the
air as it passes through the tube and thus contributing to better engine
The velocity stack creates a radius entry into the mass air sensor
reducing restriction and allowing the engine to pull in more air. Note this point is not valid for Hondas because we use MAP
air sensors which uses air pressure to measure air flow velocity. MAP
sensors do not produce any restriction to air-flow unlike mass air
FIPK on the
US Integra GSR
K&N says that fuel injected computer controlled engines can gain
substantial power by using a less restrictive air filter assembly which will
feature the two key factors of an improved air filter element and the air filter
adapter. The K&N FIPK combines K&N's famous precision high flow air
filter element with other necessary components depending on the specific
The FIPK effect is described as fully maximizing air-flow potential which
will create an instant throttle response. FIPK's are quality engineered and
dyno-tested to ensure effectiveness and durability. In the U.S. FIPK's meets the
C.A.R.B. emission standards.
K&N have also started marketing their FIPK generation 2. The main
feature of FIPK-2 is the use of an extra screen to shield the K&N cone
from the rest of the engine bay and thus providing the so-called cold-air
intake effect. However, at the time of writing of this article, K&N
does not produce FIPK-2 for any Honda models. A picture of an FIPK-2 for a
US make is produced on the right.
Like Filtercharger replacement filters, K&N produces a specific
FIPK for each Honda model they support. The main Honda models K&N
supports includes most versions of the Integra and NSX (marketed as
Acuras in the U.S.) and the Honda Civic (and CRX).
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