see post from DEC 6th re:Cabin Microfilters (brokenbat) I go through the procedure about removing the old filter material from the frames.
there was an arrow on the furnace filter to show the airflow direction but by the time I disected it I forgot what layer of the plastic gauze was on what side of the foam. Since they said on the package that it was electrostacticly charged I'm wondering if the plastic layers have to be facing any particular direction. The plastic gauze material seems to be the same on both sides and foam is foam so I don't know what sets up the electrostatic charge (I missed science class that day) or whether this is a BS selling point to make it sound more HiTech than it really is.
Performance? The blower is quieter and the temps seem to change faster when going from one extreme to another. My old filters had 56,000 on them so they were probably plugged a bit. My 0-60 times have dropped by 2.5 seconds and the wheel wobble at 100-110MPH has gone away. The only downside is the brakes which will be helped by the 'chute I'm installing
I think the real test is going to see if there is any dust that develops on the vents in the dash. On my old car with no cabin filters a thin layer of dust would develop after about a week on the adjustable vent blades and then out came the q tips if I had nothing better to do. I'm sure the passageways to these were clogged pretty good (after 256,000) and the blower motor was probably groaning with all the crud on it too. If I start to see dust develop, I'll slap another layer of foam in there.
Happy motoring- Remember that the frequency of pit stops is determined by the person with the strongest bladder, not the weakest.