Outer Limits 4x4 Board

MightyMouse wrote: And BTW is reverse blowing with compressed air effective at removing these particles ?

Sorry missed this - it works to some extent. Filters can be classified into 2 types, depth filters and surface filters. A CAR/4x4/truck air filter is a depth filter, that means that the particles will collect in the depth of the media, rather than on the surface - only later, when the filter has collected a lot of dust, will it become a surface filter (when there is enough dust that the dust is doing the filtration rather than the filter) - but by this stage you will want to have changed your filter. Most commercial depth filters are not considered cleanable by compressed air, but some are washable.

Most industrial filters are surface filters, and they are designed to be cleaned over and over again (with compressed air). Interestingly, modern tanks have surface filters, with automated compressed air cleaning - you don't want to change your filter in the middle of a battlefield!!!

So - compressed air might remove 99.5% of the dust from a surface filter, but only 30% or so from a depth filter.


As to the manometers, I have a donaldson one fitted to my donaldson airbox. It is just a simple device that measures vacuum in the filter chamber (after the filter) vs atmospheric pressure. When the filter DP is too high, a red tag pops up - and it is time to change the filter.

Just checked the unifilter website - name change is interesting, mine definitely says finer filter (btw - as I said before - free to anyone who wants it - needs a new outer band but the inner is fine).

They claim they remove all particles above 4-5 micron. I think I will have to do some more filter testing as I find that VERY hard to believe.
http://www.uniflow.com.au/contents/en-u ... filter.pdf

zagan wrote:

Gee wrote:For anyone wondering what a Finer Filter looks like:

In Australia they are only known as uni-filter.

Finer Filter is the exporter name.

same company, I'm going to pick up one of their packs, very soon.

Only as of 1st October 2006. I've had mine for more than 3 years so they were called a finer filter when I bought mine. Check ya facts

ISUZUROVER wrote:As to the manometers, I have a donaldson one fitted to my donaldson airbox. It is just a simple device that measures vacuum in the filter chamber (after the filter) vs atmospheric pressure. When the filter DP is too high, a red tag pops up - and it is time to change the filter.

Thanks ISUZUROVER have learn't heaps from your posts.

Given that a manometer seems to be the way to go, how do you determine what DP represents a blocked filter ? I suspect this is not an easy question but I have to ask .

foam oiled filters are good enough for my crotch rocket, then they are good enough for me!

Gee wrote:

zagan wrote:

Gee wrote:For anyone wondering what a Finer Filter looks like:

In Australia they are only known as uni-filter.

Finer Filter is the exporter name.

same company, I'm going to pick up one of their packs, very soon.

Only as of 1st October 2006. I've had mine for more than 3 years so they were called a finer filter when I bought mine. Check ya facts

Well as of right now, they are the same company regardless of what happened 2 years ago, a few months ago they had a message about the finer filter brand being only sold to export markets, this is gone now.

Unifilter is recognised as a major Australian developer and manufacturer of high performance air filters for the automotive, motorcycle and ATV OEM and after-markets, both within Australia and throughout an ever-increasing international market. With products manufactured under the Unifilter, Finer Filter, ProComp2 and O2RUSH brands, Unifilter’s commitment to innovation, quality and value ensures that it will continue its position as industry leader into the future.

my impression is that they were all the same company anyway, only different names for different markets. The car companies have done the exact same thing for decades with cars, engines and cars parts.

there is an USA unifilter company as well, which is separate from uni filter Australia but used to be the 1 company but have parted ways ages ago.

It's all pedantic details that don't really matter- that was my point.

cooki_monsta wrote:foam oiled filters are good enough for my crotch rocket, then they are good enough for me!

Are they good enough for your motor though?

Steve.

Toyota runs a factory manometer to indicate a blocked filter. I'm not sure of it's pressure, and I have never had one indicate, but I figure it can't be too blocked.

Autospeed did some excellent manometer tests on WRX's and 180sx a number of years back. The results were that for intake flow restriction under real world driving conditions, a paper filter, even when looking a bit shabby, was less than 7% of total intake restriction and 3% for a clean one (don't crucify me if the numbers are a tiny bit out, it was a while ago.) Most restriction was corrugated pipe, mesh screens for air flow meters, poor bends, lack of bellmouths on air filter box etc. Corrugated pipe could be 30% of total intake resctriction, it's shockingly bad.

I know these were not testing a filter that had just come back from a long bulldust trip, but it gives come comparisons.

They also did a rough test with the filters and a white cloth. Yeah, I know you could argue it, but the results matched what you would expect with the K&N and foam filters allowing far too much dirt through.

Finally, remember that it's all condition dependent. Mine trucks are very different to boats. Boats have no filter at all. My mates bore pump, an OLD southern cross diesel that does about 600RPM, uses the engine oil as a filter by drawing air through the rocker cover. It's 60-70 years old out at Roma in the dust and still going strong.

I run paper filters personally, and I don't stress on keeping them ultra clean. The car will tell me if it's a real problem, otherwise it's every 40,000km. And I do dirt touring.

Paul