Monday, November 16, 2009

Let the engine breath like we all do.....

Performance Air Filters
Performance air filters has always been a starting point for
those who want to take the first step into car tuning. This is
because performance air filters are easy to apply and are not so
expensive as other performance tuning components for your
I believe the first reason that make all of us purchase a
performance air filter for our cars is the sporty sound that we
all like, but generally there is a belief that performance filters will give you lots of
horse power, like a minimum of 5 hp, maybe more, even on a normally aspirated
Now, if I say that performance air filters generate nothing except a sport sound,
would you believe it? Your answer would normally be "No !"... Yes, performance air
filters do increase horse power but only under certain conditions.. Please continue reading the article..
Performance air filters - The Theory
The theory here is, as you let more air to the combustion chambers to mix with the fuel, you get more power, but the first
point is that under which conditions does the air flow and do performance air filters really provide more air as it has been
Aerodynamics, or let's call it air flow here, is so complicated so you can never be sure that the replacement of your
conventional air filter with an open element filter (like K&N, Kingdragon or Green) will provide more air flow to the intake
In-Box Applications
Let's discuss in-box applications like replacing the stock filter with a inbox K&N first, for those who want to apply that kind
of air filter mods. On a test which made with a test air box measuring the flow resistance of air yielded the following
(The number 100% states the maximum flow resistance to the air, meaning the air is somehow obstructed maximum by
the filter or the air box itself while passing through the combustion chambers. Numbers lower than 100 indicate that air
flows more easily relatively to the conditions represented with the number 100. It is natural that the air will flow most
easily if you detach the filter and the airbox, thus the lower number is 37.5 meaning the least resistance has exposed to
the air.
stock box w/ filter 100 %
stock box w/ K&N 100 %
stock box w/o filter 100 %
modified airbox (trimmed) w/filter 62.5%
modified w/K&N 56 %
individual filters 44 %
manifold only 37.5%
This test has shown that changing the stock filter with an inbox performance filter like K&N is useless unless you make
some mods to the airbox, but the most surprising result is that whether it's an original filter or a performance filter like
K&N, if you take one of these filters out and apply the test again with an empty air-box, there is still the same resistance
like there is a filter inside. That's really really hard to believe, but when you remember the test made with manifold only,
you see that air still has a resistance of 37.5. So, that's aerodynamics we talked before which is so hard to understand,
and it's not a big surprise that an airbox causes so much resistance.
It's clear that changing the stock filter with an in-box performance filter like K&N is useless unless you make some mods
to the airbox, and it's clear that it's not usual to drive without filter and the box, so instead of modifying the box, why
don't we use an open element cotton filter? We can get a result between 37.5 (the manifold only) and 56 (modified airbox
with K&N). Now, the most vital part of the article.. Please keep up reading..