This is an exerpt from a member from hondasuv.com:

PROS AND CONS OF USING K&N FILTER:


Pros: high air flow, reusable.

Cons: lets more dust in, the reuse oil is about $8, mess to deal with
when washing. the dust particles that are allowed into the engine
gunk up, wear out the parts faster, engine will not last over 100 000
miles.

I have turned down most of the "high flow" filters because of the
simple law of physics, in order to let more air in either have to
increase the surface area or make the pore bigger, since the K&N drop
in filter has almost the same surface area, then the pores are
bigger. the cone probably has better surface area, but i don't really
want more engine noise (from the air being sucked in)
Thanks for the advice though

Not sure I agree with the "lets more dirt in" theory. If they let
more dirt in, you would end up wearing the rings and the car would
start using oil right? (correct me if Im wrong).

Ive used either a Drop in K&N filter or an aftermarket pipe with cone
K&N on it on my last 7 cars. All went in at about 5,000 miles or s0
and stayed in until I sold the car and not one of them ever used any
appreciable ammount of of oil. Nor did I ever find fine dirt in the
intake and essentially Ive never had a problem. I clean the filters
every 20,000 miles or so. The cleaning kit lasts through prob 4 or
5 cleanings. Not very expensive considering the cost of factory
filters.

1986 Pontiac Trans Am 186,000
1990 Civic SI K&N in for over 130,000 miles
1991 Saturn SL2 50,000
1994 Civic EX 78,000
1994 Pontiac Trans Am 112,000
1995 Chevy Impala SS 56,000
1990 Honda Accord ex 130,000

Your mileage may vary and please use what you are comfortable with
but I dont think its all that much of an issue.

On the outside of the K&N package tell what % of air that K&N claims that it
filters??????
Answer: 99% what about the other 1% not much,no big deal but remember how
much air your engine uses in a minute,an hour,1,000mi it adds up to alot of
dirt in it.
You can talk till your blue in the face about low end power(where you don't
even need more airflow) it's the high RPM where it's needed,the smart thing
to do would be stick with paper but get a larger filter then get CLEAN 100%
filtered air !!!
FWIW I hope all your engines go past 200,000
Bob

Do you really think that paper filters achieve a 100%
filtration rate? How aboout maybe 80%? that is more
likely the number for a low end filter.

I do not use K&N so I can't tell you if it is good or
bad but I can tell you that paper filters are far from
efficient.

I have been using K&N filters in all my vehicles since 1991, many of
which approached 200k miles with absolutely no engine problems. I have
several friends that have done the same (one guy put 300k on his CRX and
used the same K&N filter since 50k with no problems.) Believe me, K&N
filters filter every bit as good as paper, and quite possibly better.
K&N have been renowned in automobile and motorcycle racing for years,
their reliablity has been proven over and over again.
Check this page for some more insight:
http://www.knfilters.com/facts.htm

My $.02,
Stephen
01 ITR NBP
01 ITR

I hope you got the Filter. They work.

These guys think it can't work because they dont understand HOW it
works.
K&N filters have much LARGER openings in the filter material than a
paper one. The 'paper' is not what does the filtering though. The
paper's function is to contain the oil, which is what actually
filters the air. That's how they can get more air through the same
size filter.
They've been using them for decades on racing vehicles. If they let
more dirt in, do you think race engineers would risk using one on a
$60,000 engine? Nope

Race Engineers think nothing of re-building an engine if a modification
allows them to win a race (unlike us poor schlubs!)

AB
Long Island

I seem to have come into the K&N filters right in the middle.  I read about a Tornado and this filter.  Are both suggestions for power enhancement, as in going up hills and not having to pop into 3rd gear so soon?  Does the filter help with power on its own?  And where can you buy these filters?
 
Thanks,
 
Hans

This is a huge can of worms but here goes a small attempt. Just
hitting high points. feel free to flame away.

I would avoid the tornado device as I dont think it works. Ive seen
people put it on GM V8 cars, dyno with and without and there was no
change. Yes, fuel injected computers DO learn to a certain extent
over a few hundred miles and of course there are always differences
in dynos, and air temp and pressure and humidity change and cause
changes etc etc. but bottom line is the differenc is probably too
small to measure.

The K*N filter will help. Aftermarket intakes with cone filters much
more than drop ins but even those help. Anything you do to help the
car breathe better both intake and exhaust will help TO A POINT.
Open up the intake beyond what the throttle body can flow and that
becomes the bottle neck, get a bigger throttle body and then the
valves/heads exhaust ports and cam, then headers, then size of
exhaust pipe, then mufflers in turn become the bottleneck.

BUT IF you open either end up too much you end up reducing velocity
in the system which KILLS torque and hp. Thats why a bicycle could
outrun civic with a 4" exhaust, kill velocity, kill torque, and your
are dead off the line.

Bigger engine bigger gains Putting a cold air kit with cone K*N
filter and 4" intake tube to the throttle body on my 95 Impala SS
(5.7 liter V8) netted me 17 rear wheel hp 0n the dyno with no other
modifications to the car, which worked out to 25 hp at the motor over
the stock intake.

PUt a cold air kit like that on a civic and you wont see 17, More
like 3-5, drop in K*N prob even less unless you cut the airbox to get
more air BUT then you let in hotter air from the engine compartment
and heat kills HP. anyway, smaller engine, smaller gains.

Ive used both cones and drop in K*N filters on 5 of my hondas and 3
GM RWD V8 cars so far, and ran 3 hondas and 1 trans am well into
150,000 mile territory without any adverse effects to the motor. No
oil burning, no oil use, no worn rings, no dirt in the intake behind
the filter, nothing. I have an AEM short ram on my 90 accord now,
Yes it sucks a lot of heat in with the cone but it breathes sooo much
better than the stock airbox that it ends up helping.

The diff will be felt more in the higher RPM range than down low but
in anycase I dont think just dropping in a K*N will hurt. And you
wont ever have to buy another 20 or $30 filter again.

Jeff

OK, I'm convinced on the K&N filter.  You said that I won't have to buy another filter.  Is the K&N a cleanable filter?  Where do I get one of these?
 
Hans

Yes, you buy a cleaning kit. spray the cleaner on the dirty side,
run low pressure water from clean side of filter to dirty side to
wash away dirt. Air dry it over night or for few hrs, reoil and go.

Pep boys carries K*N filters and should have the cleaning kits. Or
any online high perf parts place for hondas.