I am considering replacing the standard air filter and box on my 4.0 liter 6 cyl engine, for a none standard cone type filter, what are the implications to do with this, can the same efficiency be obtained, what size filter and other ancillaries will be required.

Regards Tom

I am considering replacing the standard air filter and box on my 4.0 liter 6 cyl engine, for a none standard cone type filter, what are the implications to do with this, can the same efficiency be obtained, what size filter and other ancillaries will be required.

Regards Tom

K&N has a custom fitted kit especially for the Jeep 4.0L engine. I only use K&N cone air filter kits in the cars I have owned: BMW X5 3.0L, Jeep Grand Cherokee 4.0L (several models) and now, a K&N tray filter in my MU-7 3.0L.

The K&N filters simply allow the engine to 'breathe' more efficiently, thus adding to the vehicle's overall performance. This will be a somewhat small increment in the overall noticeable total performance increase (7 hp - 10.+ hp [?] advertised), but together with other performance tweaks, a performance increase it is! If you couple the K&N cone air filter kit with a 'Cat-back system exhaust' - a X-pipe - you will most definitely 'feel the increase power' every time you hit the accelerator - not speaking for LPG.

K&N have a good reputation and a strong following. However there is another side to the debate, see http://www.nicoclub.com/archives/kn-vs-oem-filter.html

K&N have a good reputation and a strong following. However there is another side to the debate, see http://www.nicoclub.com/archives/kn-vs-oem-filter.html

My first impression about that would be to see a few more of these kinds of 'tests' to compare the results and to verify the testers professional independence and not marketing competitors. In this situation, I personally noted the difference (at least to my satisfaction) that the K&N CAI cone filters made in the 2 different model cars I drove at the time .... so much so that I will always use them.

I agree it's hard to judge the the validity of some of these things. Still, the test I linked does not dispute a performance gain, in fact the lower resistance curves for K&N support that aspect. The interesting point is the filter efficiency and it's ability to catch the dirt. That is going to be hard for the average user to monitor.