Don't K&N filters have to be re-oiled once in a while? Not sure about the one for the CX-9, but the one for my Audi requires it to be lightly oiled, which can be an issue if you clean it out and put too much oil back in (excess oil can ruin the mass air flow sensor)
do you have to change it per mile or per time passed?
Kindly advise.
I doubt that K&N filters improve your MPG.
More air into the engine triggers more fuel into it as well.
As a result, more torque (x RPM => more power).
In the meantime, less MPG.
I have installed mine. I really haven't driven it enough yet to notice any performance difference. What I am hoping it will squeeze a couple extra MPG out of it.
I think K&N's power benefits tend to be overstated. Any newer vehicle with a decently designed intake system and a large filter area should perform just as well (for instance, the nissan frontier actually dynoes 1hp LESS with the K&N and zero difference in mpg's).
If you have other reasons, drop ins can be good but looking for power or mpg's from them will probably leave you disappointed (or living with a placebo effect).
I jst bought mine this past weekend. The original paper filter is coming out with 37k on it, but I did vaccum and blow it out once. I can't wait to see if there is any difference at all. Hoping it might change the intake/rev sound a bit. Bottom line is the filter will outlast the car.
Did you say 37K? What type of driving conditions [environment] do you typically experience? Isn't almost 40K with the same filter a stretch?
good luck.