New air filter?

[Patrick F. Clarin]

How much difference can a new air filter make on my '02 WRX? Especially
one of those supposedly high performance ones from K&N.

 

[Richard Paquette]

How much difference can a new air filter make on my '02 WRX? Especially
one of those supposedly high performance ones from K&N.

Big difference i put one in my SVX.

Richard

 

[Edward Hayes]

Made NO difference on my 2000 Forester except made it sound louder and cost
more so now I run OEM

 

[TG]

If you go with a new intake that will accept a LARGER filter then you could
expect improvements in airflow. If you get an improvement in flow with a
stock size filter I would expect more dirt entering the intake...not good!
TG

 

[Jkpoulos7]

How much difference can a new air filter make on my '02 WRX? Especially
one of those supposedly high performance ones from K&N.

A world of difference. Better mileage, acceleration. Best easy upgrade out
there

 

[Bryan Lee]

goto http://www.subarureview.com It has all the info you will need. I 'm
not sure what TG is talking about. I have a '04 WRX and from all I have
read our stock intake is good upto 350 hp with a panel filter like K&N. As
for getting a "larger filter" such as the cold air intake(CAI) and such
will throw off The computer on the WRX. It will make the engine lean out
and ping early and make the knock sensor set the timming back and make you
loose power. TG what "larger filter" are you talking about?

 

[Bryan Lee]

also goto http://www.scoobymods.com It will show you other thing you can do
yourself.

 

[Ned Pike]

In

A world of difference. Better mileage, acceleration. Best easy
upgrade out there

Yep, and shorter engine life due to the small-size crap no longer trapped by
the air filter.

 

[Ragnar]

In

Yep, and shorter engine life due to the small-size crap no longer trapped by
the air filter.

A cite of some actual data would help a lot. Got any empirical data?

 

[y_p_w]

A world of difference. Better mileage, acceleration. Best easy upgrade out
there

I've seen dyno tests in an auto mag (Motor Trend?) showing that a K&N
cone filter had slightly improved top-end power by a few HP in a '94
Integra LS, but actually decreased lower end power (under 2K). I think
Honda got it right with a dual stage intake that opens up at higher
RPMs. Restricting the airflow is supposed to help with lower end
power/driveability.

I agree with some of the other posters that it may do more harm than
good unless there's some modification to the engine computer to account
for the increased airflow. I also recall K&N's own info saying that
paper filters were better at trapping contaminants.

 

[David Betts]

In

Yep, and shorter engine life due to the small-size crap no longer trapped by
the air filter.

Absolute rubbish. Proper performance filters are just as effective as
the standard part, if not more so. You simply have to remember to
re-oil them every 10,000 miles or so - or more frequently if you live
somewhere with a lot of airborn dust or drive off road. Other than
that, no problem.

Not sure that K&N is necessarily the best bet in a Rex, though. I'm
pretty sure Scoobysport recommend something else. Take a look at their
web site.

David Betts
(e-mail address removed)

 

[busterb]

"

Yep, and shorter engine life due to the small-size crap no longer trapped by
the air filter.

I somehow doubt that. Put a K&N in my 94 Trooper at about 15k miles.
Still had in in there at 145K when it was totalled. NO engine issues
whatsoever.

 

[jMon]

My understanding, admittedly limited, is that "Yes" the new (K&N or
similar) air filter will enhance performance on a race track but not
in real world driving.

 

[y_p_w]

Absolute rubbish. Proper performance filters are just as effective as
the standard part, if not more so. You simply have to remember to
re-oil them every 10,000 miles or so - or more frequently if you live
somewhere with a lot of airborn dust or drive off road. Other than
that, no problem.

Not sure that K&N is necessarily the best bet in a Rex, though. I'm
pretty sure Scoobysport recommend something else. Take a look at their
web site.

I've used a K&N filter before. Their own literature claims that their
oiled gauze filters are more effective at trapping dirt when dirt has
already built up, which increases the surface area. Of course when
the dirt builds up, there's going to be more restriction.

 

[David]

A world of difference. Better mileage, acceleration. Best easy upgrade out
there

I sort of believe, but may need a little more convincing. Anybody do a G-Tek run
before & after?

Actually I'm a lot more interested in how it affects an NA 2.5l Sube than a WRX.
Still hard data beats "butt dyno."

 

[Jim Untch]

This subject comes up quite frequently on the Mazda Miata ng too. A friend
of mine on "scoobymods" (Peaty) got me to put a K&N in my 97 Outback back in
1999. He also talked me into removing the air "snorkel" from inside the
passenger side front fender, in order to get more cold air into the air box.
I probably gained maybe 1 or 2 hp from what I've been told, but the engine
seems to spool up much quicker. I'm really happy with my K&N. After I
removed the snorkel, I get a audible humming noise, that some people might
find annoying. I put a K&N in my 99 Mazda Miata, and I didn't notice any
performance increase, but I'll still keep it in there. Peaty, and others
have recommended re-oiling there K&N yearly...I usually do mine every other
year (about 16K miles). As far as more dirt getting into the
engine...probably right. What does that mean in the long run? I'll only
get 220K miles instead of 250K miles???? Take care...jim

 

[Ned Pike]

In

I've used a K&N filter before. Their own literature claims that their
oiled gauze filters are more effective at trapping dirt when dirt has
already built up, which increases the surface area. Of course when
the dirt builds up, there's going to be more restriction.

I was speaking to cone filters, not the oiled gauze panel filter.

 

[y_p_w]

In

I was speaking to cone filters, not the oiled gauze panel filter.

What kind of cone filter? K&N makes all sorts of drop-in replacement
filters in panel/cylindrical/etc shapes, as well as "universal" cone
filters with special air boxes that replace the factory ones.

K&N certainly isn't the be-all or end-all of air filters. Using an
oiled-gauze filter requires a compromise in engine longevity, low-end
power/driveability, and noise levels.

I'm a bit wary about the mileage claims. Regardless of all the other
stuff, I'd think that if they really did provide consistent 2-5% mileage
increases, most manufacturers would use them to increase the CAFE
ratings. I once bought one for $30, so I'd guess that a carmaker could
likely get them in bulk for $15-20. Ford and Honda have been going to
5W-20 oil to try to raise their mileage by less than 1% compared to
5W-30 oil.

 

[Jkpoulos7]

I'm a bit wary about the mileage claims. Regardless of all the other

stuff, I'd think that if they really did provide consistent 2-5% mileage
increases, most manufacturers would use them to increase the CAFE
ratings.

RXP gas kicker significantly decreases emissions so why doesnt exxon et al add
it to fuel? Money. How much more do slightly better speakers cost in bulk?
Automakers do all they can to pinch every penny from production costs.

K&N certainly isn't the be-all or end-all of air filters. Using an
oiled-gauze filter requires a compromise in engine longevity, low-end
power/driveability, and noise levels.

IMO it is, Improvements in all you mentioned
plus it lasts forever,

 

[David]

I'm a bit wary about the mileage claims. Regardless of all the other
stuff, I'd think that if they really did provide consistent 2-5% mileage
increases, most manufacturers would use them to increase the CAFE
ratings.

Agreed. I think they invest a tremendous amount in meeting CAFE,
and pulling in the opposite direction is the fact that americans want to
buy bigger, faster cars and trucks. If it were an easy way at that price
to help meet CAFE requirements, I think they'd be all over it.

OTOH, a filter that requires proper maintanence, and if improperly used
(e.g., over-oiled) can damage the MAF sensor (do current Subes use MAF, or
do they now use a MAP sensor?) is a liability.