Outer Limits 4x4 Board

i work for nissan and in my vision u shouldnt us the oiled type filters as i have sen the oil from these filters damage airflow meters and as some of you may no they are not cheap

NJ SWB wrote:Ben

I read the test report in the link, and it's a bit of an eye opener.

How much do you know about the procedure used? I'm wondering about the oil used in the foam filters. If they're measuring weights before and after the test, are they controlling for any oil which may be blown out of the test filter, and collect in the downstream filter? I spray mine with an aerosol, which I presume contains volatiles. Any idea if it's significant?

Cheers,

Scott

Scott, if they are doing the test properly they should do a mass balance from the filtration efficiency measurement to determine mass collected by the filter (i.e. mass per unit air volume measured before and after the filter) - and they then should correlate this with the filter weight before and after - both should be in agreement to within about 5%. EDIT - the test also has a 100% efficient filter after the test filter - which is also weighed before and after the test.

If you use an aerosol based oil then then you will get some evaporation of the volatile components, but (1) they should have allowed for this, and (2) it would be insignificant compared to the mass of dust collected.

Blow-off of the oil can occur (see post by kegz above). I have been working on looking at blow-off of filters loaded with oil for another application. In my opinion, based on the typical filter porosity and oil viscosity, blow-off of the oil would only be likely to occur when the filter was too heavily oiled to begin with.

fnqcairns wrote:Ben thanks for the information I will begin chasing up something within those brands to suit.
Nano fibres I guess will be out of my price range for a general muckabout vehicle but interesting non the less.

cheers fnq

Here is the donaldson air filter website - any reputable truck parts supplier near you should sell donaldson filters.
http://www.donaldsonfilters.com.au/prod ... &intT2ID=1

And the Mann Filter website. Mann+Hummel tend to concentrate on OEM applications rather than aftermarket, so chances are that you can only get a Mann Filter if they either made the OEM nissan filter or it is a common size.
http://www.mann-hummel.com/airfilters/i ... 15.1.0.1.1

In my 80 I use a K&N on the street and a paper filter in the bush. A mate once told me that genuine Toyota filters can be washed in the washing machine by dropping them over the agitator and giving them a gentle wash. Who has heard of this, is it a good idea or would it damage the filter? My guess is that dust could end up getting washed into the "clean" side of the filter.

I was just browsing and came across the Unifilter website..

The Finer Filters claim 4 micron filtration with increased airflow...
The normal Unifilter is advertised as Heavy Duty for On and Off road use.. although the Finer filter is marketed for extreme conditions... It has a ribbed outer filter layer and then an inner layer.

Anyone have thoughts on these types of filters with 2 stages?

http://unifilter.com.au/replacement_filters.asp

HotFourOk wrote:I was just browsing and came across the Unifilter website..

The Finer Filters claim 4 micron filtration with increased airflow...
The normal Unifilter is advertised as Heavy Duty for On and Off road use.. although the Finer filter is marketed for extreme conditions... It has a ribbed outer filter layer and then an inner layer.

Anyone have thoughts on these types of filters with 2 stages?

http://unifilter.com.au/replacement_filters.asp

IME they would be no better than the other oiled foam filters in the test results above.

And what does 4 microns mean? 1% removal, 20% removal, 50% ? - Have a look at the graph I posted on filtration efficiency - filters don't work like seives - an air filter that removes all particles over 4 microns is still not a very good filter - and I bet if they are quoting this size, they are getting 50% removal at best at that size.

mickledoo wrote:In my 80 I use a K&N on the street and a paper filter in the bush. A mate once told me that genuine Toyota filters can be washed in the washing machine by dropping them over the agitator and giving them a gentle wash. Who has heard of this, is it a good idea or would it damage the filter? My guess is that dust could end up getting washed into the "clean" side of the filter.

I would not reccommend washing any cellulose fibre (paper) filters. The filter may look fine when it has dried, but there is a high likelihood tearing or pinholing of the media once you start using it again.

Some genuine Toy filters are washable and have instructions on the steel endcaps ie fj40
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