CRD Air Filters - Revisited

[glend]

Over the years there have been a number of threads here and on LOST, KJ Country, and other forums concerning the use of various air filters on the KJ CRD. People always seem to try out the K&N drop in filter, and I know that CRDSTU, Wilmo and Palla all had some rather negative things to say about their dust stopping ability. Maybe that was due to improper oiling, but I ran across a post from a US forum where a Chrysler Jeep Service Manager suggested that the oil from the treatment was affecting MAF and other intake sensors - although once past the MAF the oil blowby gases would be mixed in anyway, so maybe its was just a MAF issue.

I know the WIX is highly regarded in the US. I always use the stock paper filters but admit that on my Desert Trip and the Cape Trip that fine dust does get past the filters, and can be seen on the inside of the air box hose going to the turbo. Changing filters more often helps, but you can't really clean the stock ones very well, other than tapping them out at the end of the day. I went through three filters on the Cape trip (thanks mainly to the dust on the Development Road) and put a new one in at Cairns for the trip home.

So let's hear it, what do you use? and why? What research have you seen to back up any one being better than another, etc. (a quick Google of Jeep KJ air filter dust; will find a number of threads in various forums that make interesting reading.

Also does anyone run a cyclonic snorkel head or pre-filter Uniflow or other head or sock?

I noticed that Airflow specifically states that:

...re a Cyclone Separator ....in harsh conditions where the environmental conditions are such that vision is impaired by dust, rain snow or bugs, a cyclone separator non-ram type should be used. This will not damage the engine duct and flow restrictions. The use of this type of separator will however reduce performance and economy.

[layback40]

All diesels have similar requirements for filtration.
Forget the prefilter. The cyclone is the best bet.
K&N are not seen on earth moving equipment. Try loading an elevating scraper with a tail wind some time & you will know what dust is !!
Cat warranties are void if K&N elements are used. You can work that one out!!
Some time when you see a big yellow thing working making plenty of dust, take note of its air filtration. Always the inlet is up high & a cyclone.
You need to go & see a Donaldson specialist some time & get the correct sized cyclone. If its not correct, it is useless. A fleabay one is an unknown. it may work. If you find out what Donaldson recommend, you can get the dimensions, especially the internal ones & see if the cyclone you have is the same. Internal bowl side angle & inlet flute angles are critical for it to work efficiently.
Typically a scraper needs its cyclone emptying daily when in dusty conditions.
If you have dust getting through your filter, you have a problem. As the filter blocks air often gets around the sides of the element. You dont need to bash the element to get every last spec of dust out. A few light taps getting 90% of the dust out is all that you need. Typically a pile of dust of equal area to the filter a mm high would be a filter that is due for cleaning. Any damage to the paper & you replace it.
In dusty conditions its best to carry a spare. Make sure its well protected so it doesnt get damaged ~ something better than just leaving it in its box.

If you hadnt worked it out already, I have earth moving equipment. My jeep gets around sites in the dust regularly. I clean the filter weekly at least. There is no dust getting past the filter. I have not got around to fitting a cyclone but it will be a Donaldson when I do.Probably if I asked nicely, my filter supplier would give me one for my birthday.

[axiom]

Thank for the information Layback, this can also be taken into account with the 3.7 however our airflow volumes are less than the turbos. It has been mentioned before by many KJ owners on both lost & here, that the snorkel gives the petrol a little bit of a boost, because you are picking up cleaner cooler air.

However if you are forcing dust down the throat of the snorkel you will be doing more harm than good, I can also say from experience the pre filters do nothing, they are nothing more than an oily stocking(albeit thicker) stuffed into the snorkel. However i have used K&N Filters before, and the ability to be washed in most clean water sources comes in quite handy. (River campsite more like remote filter washing station)