Re: Drilling holes in airbox -Reply second reply loooooooong....

["Meron" <phwomp@cosmoslink.net>]

>Obviously the last category is best. I haven't looked at Audi filters
>however K&N came up best on both filtering and flowing in independent
>tests of after market filters by a long way. I have the flow/filter
results at
>home and can post them if someone is interested. Just because it flows
>poorly it doesn't mean that it filters well as the figures demonstrate.
Fletch,
Most (I don't know any that don't) engines use air filter media for a
variety of reasons:
1.No maintenance, when it flows poorly, replace,
2.Doesn't depend  on maintenance, meaning that if your filter is not oiled,
you are not getting dirty air, just less air, 
3.Most heavy duty engines use an indicator that is calibrated (in  H2O) to
indicate extreme resistance (replacing time),
4.An air filter will just get plugged, but normally will not allow dirty
air, just higher restriction (less power),
5.A metallic filter (strainer) will allow dirty air in (especially with a
turbo) when is not maintained,
5. On some industrial engines there is a foam precliner (ahead of the
filter) to allow for better filtering in extreme conditions,
6. The issue of restriction is not a big one on turbo engines, since the
engine has a strong suction ability,
7. On a naturally aspirated engine the issue of flow is much more important
since the engine has a lot less (than a turbo) suction power,
8. Some time an OEM has a poorly design air intake, in that case drilling
holes, reversing the cover (ALA Chevy) or any other ways will result in
additional air in, hence more power, a simple test is: remove your filter,
drive around, do you feel a power increase? if you do your filter is a
restriction, if you don't, don't mess with it, stick to OEM set-up, just
replace the filter regularly..
In summery paper media is considered the most useful filtering set-up, the
oil bath set up is not used (much) anymore.. the KN is just an strainer
with some oil to catch the "big matters"...
Avi Meron