I have a 99 Forester (Canadian) and it has TWO air filters. Before someone object, there really is a filter inside of each of the two air boxes - one by RH side fender & one by the throttle body. I understand most Subbies only have 1 of the 2 boxes occupied. (refer to post "Why two air filters? May 31, 04". I'm in the city so I've decided to take 1 of them out to free up some restrictions. The question is, which one??
The first air filter box (RH side fender) is right in front of a sensor. I would rather have filtered air being picked up by the sensor... so, on to the large air filter by the throttle body. But when I take out the air filter out of the large box by throttle body, the filter box don't really seal properly without the rubber frame of the filter.
So, what ya think? Just live with two air filters? What kind of improvement, high/low hp and fuel efficiency, can I expect with less air flow restriction?
Thanks for any input.