Air Intake Facts
Upgrading your standard air intake system is one of the easiest, and most cost effective ways to improve your vehicles sound and performance. However, you need to understand some facts about air intakes before choosing which air intake to buy; their functions, their limitations and your expectations.
Air Intake - Primary Functions
The main reasons we all drive around with an air intake system in our cars is to (a) filter the air, and (b) attenuate the noise. This can be proven simply by removing everything on the intake from pick-up to throttle, and drive around (not recommended). The intake noise would be high, and your engine would suck in potentially harmful particles which could after a while damage it considerably.
The noise from the intake has to be reduced to meet certain legislative requirements, and this is done by adding a length of pipe, this length can remove a large proportion of unwanted frequencies, and further reductions can be had by installing additional small closed volumes - or resonators - which are tuned to cancel out the other frequencies. All this takes a lot of development, but at as a consequence adds a large amount of restriction up to the throttle - typically around 4kPa.
It's the smaller particles (less than 80 microns) that enter the engine which find their way in between moving parts that can cause the most damage. These particles can wear down critical areas around seals and gaskets which could easily lead to leaks and failures. The standard filters have been developed to capture these smaller particles, and tested to measure filtration efficiency (percentage of particles captured by filtration media), which most OEM's insist should be over 99%. Paper filters easily achieve this with efficiency levels of around 99.5%, but do add a further restriction to the system of around 0.5kPa.
Performance Air Intakes
By reducing the air intake systems restriction, you are allowing the engine to breathe easier, which can influence the engines responsiveness which could improve torque and power levels. However, what ever you decide to do will alter the primary functions of your vehicles air intake; noise and filtration efficiency.
An improved intake noise is one major reason why we buy performance air intake kits, so this alone is not a serious issue, the filtration efficiency levels should however be considered, as this could certainly have a long term harmful effect on your engines durability. There are many performance air filters on the market, all have varying degrees of efficiency from Oiled Cotton (circa 90-97%), Foam (circa 85-90%) to Mesh (Less than 80%)*
Therefore we recommend you choose a good quality oiled cotton filter with efficiency levels of 97%, and this can reduce the filters restriction by around 60%. This however equates to just a drop of 0.3kPa, 7% of our total systems restriction, which may provide some very minor improvements in performance. The major gains can be had by improving the restriction levels in the system as a whole including the filter. By replacing the standard system with a complete performance air intake kit, we can in some cases cut the overall systems restriction by around 60%, this equates to a system drop of 2.7kPa which would certainly aid in the engines breathing and would give improvements in vehicle performance - especially when combined with an ECU remap or engine re-calibration.
* Tests conducted to ISO 5011