FWIW. I just sent this reply via Pm to a member asking about the Amsoil Ea series filter for his 08 Liberty.
MNKK wrote:
Just curious, what are the benefits of the air filter? I used to see alot of sport compact owners using K&N drop ins, and they all seemed to be happy. does it provide a substantial increase anywhere?
If you do some research on the K&N you will find unhappy people in areas where dust is a concern. (I see them on off road forums all over the Net) K&N filters are made to flow more air.....at the expense of Some filtering ability. Most of my wheeling experience has been in areas that have fine dust and I have consistently seen dust in intake air tubes w/ K&N filters even on street driven vehicles.
I used to love K&N but not any more. (*mostly because of the drag race flow performance they offer, filtering is hardly necessary on most drag cars though) Oiled air filter technology is ancient and unneccessary. The dry filters on the market such as AEM, Amsoil Ea series, etc. do not require oil to help filter the air and they flow as well as K&N and filter Better overall. Airflow in filters is a trade off, you can't have Zero resriction air flow all of the time and expect that a filter is doing it's Main job which is filtering. I personally don't want any extra crap in my engine so I use the Amsoil Ea filters. If I wasn't an Amsoil dealer I would Still use them as I feel they are the best on the market based on the research i have done into the other Dry filters. Marginally better in my opinion but that is all it takes to sway me. (also cheaper for me too as a dealer)
As far as providing a substantial increase, No. I am a firm believer that No drop-in or even "CAI" kit provides any
major improvement over Most stock intake systems. 3rd party dyno tests have shown very small HP or torque improvements that could be attributed to other factors such as air temp, barometric pressure changes, changing from a dirty to clean filter, etc. Heck, I feel a performance increase and see better MPG's just by changing to fresh spark plugs. Todays engines are tuned better than ever to optimize fuel consumption and performance and there is very little to be gained by just switching air filters. I say that a fresh Wix air filter will show close to the same dyno gains that a fresh oiled K&N will.
I also believe that the "CAI" intakes, custom air tubes, etc. are bogus too. They may show a small improvement but at the price you pay it isn't worth it and unless properly built, insulated and routed, cold Air isn't what most of them draw in from underhood in the engine compartment w/out having some fresh air source coming to the filter from outside.
As you can probably tell, I am not sold on K&N or most "CAI's".
I use the Amsoil Ea air filter because it is affordable, flows well, filters great, uses No oil or special cleaners to clean and is reusable. The truth is that a Wix air filter will work fine and filter well but you just throw it away when it is dirty so I go w/ the Amsoil Ea.
BTW, As of right now I am not showing an Ea series for the 08 Liberty. Can you measure the factory filter dimensions and LMK. I might be able to find out it is a common size.
Hope that long winded explanation helps. You will find Many different opinions on the subject so do your own research and draw your own conclusions. Unless you plan to keep your vehicle for a Long long time it is probably not a big deal what you use as long as you take good care of it.
John
* "back in the day" I saw consistent improvements in ET by just removing the K&N filter from the ram air of my 68 Buick GS 400 that I drag raced. I know of others that saw improvements by doing the same too. Of course I used it on the street to keep the bugs out because of the ram air.