[zukenutter]

Give reasons for your preference based on your own experience

[zukenutter]

Have been using them for 15 years without a problem.

Have noticed slight improvement in performance but nothing significant.

They take some time to dry when cleaning but it's reasonably easy to do.

They are extremely durable.

[shep]

standard paper. i dont like foam filters as they don't seem very durable.
K&N are great on the road but they don't filter fine enough and i have had 2
that where faulty from brand new but didn't notice until i washed them for the first time.
standard paper filter's filter well and are cheap.

[Damo]

Standard paper for me too.

For 99% of zooks you are never going to need to pull so much air through it that a standard filter is going to be a restriction. I mean look at the surface area, it's huge.

You can blow them out with compressed air a couple of times before replacing them too.

[Scrawny]

I've seen intakes after the filter coated in dust when using the re-usable filters. You can just imagine what got into the engine. I also don't like blowing out paper ones, just bang them on the ground to get the worst of the dust out.

[Damo]

ScrawnC wrote:

I also don't like blowing out paper ones, just bang them on the ground to get the worst of the dust out.

Is that because you can blow a hole through the element?

[jonga]

no pod filters? lol

[zukenutter]

jonga wrote:

no pod filters? lol

OOPS - I did have an "OTHERS" option but it hasn't shown up and I can't edit it now. Oh well!!

[BlueSuzy]

I has a pod filter

[Scrawny]

Damo wrote:

ScrawnC wrote:

I also don't like blowing out paper ones, just bang them on the ground to get the worst of the dust out.

Is that because you can blow a hole through the element?

If you put 120psi through a paper filter that is designed to filter down to 25 microns it will soon rip it apart. You just can't see the damage you've done.

[TheOtherLeft]

The paper filter for my J20A is the same sized filter for the V6's, so in effect I have an oversized filter for my engine

[jonga]

whats wrong with having a pod filter and what would be its upsides, im thinkign about replacing my air filter too

[shep]

jonga wrote:

whats wrong with having a pod filter and what would be its upsides, im thinkign about replacing my air filter too

if you drive anywhere near wet stuff ya really want to keep an airbox

[Reubs]

Reubs wrote:

zukenutter wrote:

Hi reubs what reasons do you prefer UNI over K&N. Just wondering.

I have 2 coilies Sierras. My silver daily driver has a Unifilter My Bro did about 100,000km on the unifilter before I bought the car. My white one that was in Tough Tracks has a K&N and I have done about 40,000 with a K&N filter in it.

Construction:
A Sierra Unifilter is made from a removable 2 thick layers of different density foam, wrapped around a steel mesh frame. The seals between filter and air box are made from the same foam as the filter.

A Sierra K&N filter is made from permanently attached 4 thin layers of cotton gauze, held between fine steel mesh molded into a plastic frame. The airbox/filter seals are a pair of moulded ribs in the plastic frame.

Cleaning:
Unifilter takes about 5 minutes to clean with ordinary turpentine, and re-oiling is done with generic (you can buy genuine if you wish) air filter oil.
You can squeeze the dirt and turpentine out of it like a sponge. This is very quick.

K&N takes about 5 hours (1/2 hour working, 4 1/2 hours waiting). First 20 minutes of cleaning with (CAN ONLY USE GENUINE) K&N cleaner and LOW pressure water, then it needs to dry completely before oiling, otherwise the water will repel the oil. This takes 4+ hours even when left in the sun. Then oiling with (CAN ONLY USE GENUINE) K&N oil requires even spraying over the pleats in the guaze. Filter needs to be left for 10 minutes at each application of oil to ensure it works into the cotton. This process needs to be repeated until there is an even "red" application of oil.

Performance:
Unifilter - you will notice even when the outside is covered in dirt, the dirt hardly makes it to the outside of the inner layer of the heavier density foam. It seals itself in the air box via the foam seals very well.

K&N - The cheap seals are useless if your airbox doesn't close properly, and the oil on the inside of the filter still manages to trap dirt to the filters insides. Does this mean some grit gets through the filter?

Cost:
A Sierra Unifilter is $65, and is cheap to service.
A Sierra K&N filter is $110 and I get about 2 1/2 services from a $29 (repco price) recharge kit.

Verdict:
IMO, A Unifilter is better at filtering, more ruggedly constructed, easier to clean, and cheaper to buy and service.

Also, the K&N 1 Million Mile guarantee is void if the filter is used "off-road". In that case it is 12 months only. K&N's main marketing point is no good for the off-road industry IMO.

[Reubs]

shep wrote:

jonga wrote:

whats wrong with having a pod filter and what would be its upsides, im thinkign about replacing my air filter too

if you drive anywhere near wet stuff ya really want to keep an airbox

Or on any unsealed road... unless you enjoy cleaning your filter all the time!

[eldo]

the standard paper type is the go, i little grease around the outlet of the air box (after the air box) will help catch any dust that has made it through, thats my helpful hint for the day

[twitchy]

Uni filter has been successful in the motorcycle industry for years, they know there shit, cleaned correctly, oiled & grease on the sealing edges & there should never be any dirt get through.
I voted K&N before I thought about it but I changed my mind.......

[Saam]

i use silkolene foam filter oil seems to work on my k&n never dirty inside the airbox



iii dunno

[buzbox]

The previous owner had installed a Uni filter foam air filter into the standard airbox. Personally I've always used K&N.

You can buy a foam precleaner for the K&N cotton filters, they're particuarly suitable for extremely dusty conditions. Kinda fit's over the filter like a sock.

[zukenutter]

Some interesting polling and comments so far. It's very interesting to read the strong leaning towards the paper filters. I'm thinking I might swap the filters in our 2 Jimnys for a while. The stocker has a paper filter.

[Saam]

i have a jimny paper filter sitting here in an airbox, looks like a cabin filter it's black lol

[steak_knife]

I use K&N, used to use uni sock`s on street car`s & bike`s & never had a problem either, But i couldn`t find a uni for a Gv so K&N it is.

Pod`s? No thanx!!

[alex]

i have a k&n air filter i use the k&n cleaning kit never see any crap in the air box

[Gwagensteve]

There's masses of tech posted by Isuzurover on Outerlimits, who is a filtration engineer, on the performance of K&N filters.

I have experience with K&N, Unifilter and paper.

K&N do not filter well enough for off road use. They might be suitable for on road use.

Unifilter are a complete PITA. They might be great on a motorbike, but they stop an airbox designed to let heavy material fall off the filter and collect in the dust trap from working. The end result is a big mess of sticky junk stuck to the filter, leading to lots of maintenance.

There seems to be a lot of misunderstanding about the way air filters work. A properly designed air filter works best when it's very, very dirty. In fact, eventually, it will work so well it will prevent the engine from breathing. The best advice for helping your motor to last is to fit a paper filter and don't touch the thing until you perceive a drop in performance. Most heavy equipment uses a telltale light to tell you when this is. For most of us, it's probably about once a year - funnily enough, when the factory normally recommends a filter change.

Many people believe that fitting a low restriction filter will improve engine performance. It's not normally detectable. What many people do is remove a dirty paper filter and fit a clean low restriction filter. That's not a fair comparison. The filter element is almost never the cause of measurable restriction - it's nearly always the piping to and from that's the problem.

Another point - serviceable "low restriction" filters generally have less surface area than paper - that means that service intervals are shortened, but how do you know when it needs servicing? Pressure drop is generally never measured, and K&N don't "clog" like paper - they can actually start to pass quite large material (big enough to be visible) once they get dirty.

Generally, if your filter element is a restriction, that's a sign you need a larger element, not a smaller one that doesn't filter as well like a unifilter or K&N

I've taken to using 1980's hiace air cleaners in my cars. The element is about twice the size of a 1.0 element, there's an internal cyclone, the can is steel so it can be readily modified, and it is very well sealed. It's kind of a copy of a 6" donaldson cyclopac.

As an aside, you will never, ever find a heavy equipment manufacturer (truck, earthmoving, forestry, agricultural) that has ever used a reusable, cotton, or gauze filter. We need to look to the people that design filtration systems for off road conditions, not race cars or ricers.

Just my 2C.

Steve.

[royce]

It's interesting that when you read the speal on K&N it was actually designed for off road racing a long time ago, the thing that it and unifilters have in common is the media doesnt filter anything at all the theory is that the particals are trapped by the oil when they hit it, unifilter has the supposed advantage here in that the foam doesnt allow a straight path for the air so is likely to trap more.

I have used all of them, they all have their strong points and all were the best option for the application now I have a clogged up 3 yo ryco in the vit cause it doesnt see any dust to need anything else

[shep]

it is amasing what my snorkel pre-cleaner traps

[steak_knife]

shep wrote:

it is amasing what my snorkel pre-cleaner traps

An old mate used Donelsons & no filter`s in his beach buggy`s, seemed to work...