Outer Limits 4x4 Board

This is just a warning to people using oiled sponge filters and cotton filters.

I drove in convoy the other weekend, kms of very very dusty driving. Dusty enough to be coughing up brown phlegm.

I still stand by the fact that as a trade off of performance and filtering a good well oiled uni filter does very well. But it misses the very small particulates.


Ill let the pix do the talking...




Nice and clean on the inside still...



But then this...

Have you tried it with the outer sock on as well?

Cheers

these filters were custom made, i didnt get an outer filter for it. I may do now though.

That is a lot of dust... I might go put the paper filter back in the zook now.

That looks pretty crap, but it doesn't look much worse than I found downstream of a Ryco paper filter.

A cheap paper filter won't necessarily be better.

eeww.

Twin filters? + reverse snorkel head in convoys

Filter is working fine, you have a air leak is after the filter.

Z()LTAN wrote: Dusty enough to be coughing up brown phlegm.

How far apart were you diving in this convoy???

All there 4wd filters have 2 layers of foam as they are different grade foam. I have run Uni filters for 6 years on my patrol with both filter layers and NEVER had dust past the filter.
Get the 2nd filter on it!!!

We've had some EXTREMELY knowledgeable people on this forum look at foam filters and it makes very interesting reading.

From a technical point of view I'd summarize it as "not a good idea" on their own.

I run an oiled foam precleaner in the snorkel head AND a quality paper filter in the airbox and IMO that's a good combination for clean air.

The oiled foam picks up an amazing quantity of crap with the paper doing the final cleanup ( and lasting many many times longer in the process ).
If your away for a few days then washing / changing the precleaners is very effective and easy.

Yes it does add more intake restriction........ but IMO you have to trade that off agaist the effects of a blocked or ineffective main filter.

turbo gu wrote:All there 4wd filters have 2 layers of foam as they are different grade foam. I have run Uni filters for 6 years on my patrol with both filter layers and NEVER had dust past the filter.
Get the 2nd filter on it!!!

Hi all...I,ll 2nd that.You should have 2 different grade foams for your filter,One fine the other coarse.You should allways use grease where the foam meets metal plastic ect or anywhere where you think dust can get thru.

Dirt bikes have used foam filters since the dawn of time and its common practice to use grease where the foam contacts other surfaces.

Never have i seen dust get past a correctly fitted foam filter.

I was always told by people to just use the paper throw away filters but when my local shop sold out of filters that day and i needed one he sold me a uni kit for my 80 series for 50 bucks. It came with two outers to change over and every 5000kms the core and cleaning shit. I noticed a difference straight away when driving around and could hear more air sucking into the snorkel. When i go away i'll fit the pre cleaner to the snorkel and keep cleaning that regularly. That said my mate had a navara with one and we did 50kms of dusty driving and his caked up with a thick layer of dust which was like mud where the air was going in. Dunno if he over oiled it or because he modded his air box or not. Another mate just got back from cape using a k&n so i've gotta check out how he went with his.

There are plenty of test reviews on the web that show paper gives the best filtration over foam.

Foam flows better because the holes are bigger. THe oil does not compensate fully for that.

Googel will prove that out.

Autospeed did flow tests and showed that paper air filters made up 10% or less of total intake restriction with the 90% being corrugated pipes and poor (non bellmouth) transitions from airboxes etc.

Paper is good.

Paul

This has been a fairly difinitive guide for me. Good study on various filters done under controlled conditions.

http://duramax-diesel.com/spicer/index.htm

Of course it does not go into the oil filter pre filter with paper filter main scenario described by MIghtyMouse.

IMO oil filters are only needed if there is an expectation that the filter will get wet. (hence why they showed up on bikes first). Paper filters clog faster n' hell when wet. Not saying this is gosple truth just what I've always understood to be the case.

PCRman wrote:IMO oil filters are only needed if there is an expectation that the filter will get wet. (hence why they showed up on bikes first). Paper filters clog faster n' hell when wet. Not saying this is gosple truth just what I've always understood to be the case.

That's a good point. All my dirt bikes have come with an oil foam filter from the factory but how many cars come from the factory with a foam filter?

cheers

this has nothing to do with the Uni filters ....but what is a bit of dust

i went to put a new filter in as i didnt know when it was the last owner did it...

HAHAHA I think my dad might have owned that car! lol

I want to see the oil filter!!!!

The council called - they want their bitumen back

Nat84 wrote:this has nothing to do with the Uni filters ....but what is a bit of dust

i went to put a new filter in as i didnt know when it was the last owner did it...

HOLY MOSES!!!!!!

You could mulch an entire suburban block with that

At least your fuel economy and power will increase.....

lol. That paper filter did its job

I have the same type of filter but mine also has a pre cleaner on the outside

Great photos, thanks guys.