AFTER hearing a few stories about the standard airbox and filter on 79 Series Land Cruisers, I decided to look to the aftermarket for one that could deliver cleaner air with less chance of dust slipping by the air-cleaner element. I’m not a great lover of flat-bed air cleaners anyway – you don’t see them on hard-working interstate trucks, do you? After some deliberation I settled on an airbox and filter element from Fatz Fabrication in Rockhampton.
The specs looked pretty good, with the Fatz AirBox capable of flowing 1090cfm compared to the standard unit’s 680. In addition, a standard Cruiser air-cleaner element has a surface area of less than 800cm², while this new filter has a surface area of more than 1200cm². That will increase airflow and, importantly, maintain the cleanliness of the air going to the engine. The unit is also a lot more compatible with the Safari Armax snorkel I have fitted.
There are two filter elements to choose from: a normal paper element or an oiled gauze unit. These are custom-built for Fatz by Custom Built Motors (CBM) in the USA. Mine, bought about nine months ago, is actually branded CBM but the filters are the same.
CBM claims its seven-layer filters outperform the three- or four-layer K&N filters and, while there may be some truth in it, I’ll put it down to marketing aggrandisement. Fatz claims the filter it uses is an eight-layer unit, and while you can build more layers into a filter and thereby increase its efficiency, you decrease its ability to flow air. As the Donaldson website (www.donaldson.com) testifies, the efficiency of the filter improves as dust accumulates on the surface of the filter, so an air filter gets better as it gets used – until it restricts the air too much.
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Most engine wear is caused by dust particles that are 10 to 20 microns in size (a human hair is 50 microns), and the ability of an air-cleaner element to remove particles is measured against the testing procedures laid down in ISO5011. The results of the test are measured by a specific air-filtration efficiency number. The oiled filter element from CBM is rated at 99.3 to 99.5 per cent efficient, while the dry filter is slightly better at 99.5 to 99.7 per cent efficient; but the oiled filters work just fine if you maintain the filter properly.
We’ve done 22,000km with this new airbox and CBM filter; 9000km of that in very dusty conditions travelling in an outback convoy. The filter has collected a little dirt and dust, as well as a zoo of insects, and while it could have gone longer before being cleaned, I wanted to clean it before the 79’s next outback jaunt.
I tend to use a Unifilter Snorkel Pre-Filter in dusty conditions, changing or washing it more regularly than the main air-cleaner element. A custom pre-filter is available from Fatz for the main filter element, but the Unifilter is easier and quicker to use; although, as it is smaller it probably loads up with dirt faster.
To clean the filter I use a K&N filter cleaning kit that includes a pressure spray cleaner and an aerosol oil spray. You first spray the element with the cleaner fluid and allow it to soak for 10 minutes or so, before rinsing the filter with water. Allow the filter element to dry and then spray it with the oil, ensuring the oil is spread evenly over the entire surface. It might need a second coat.
These kits do about three to four cleans and resprays of the cleaner element … and I’m probably a little heavy handed with the oil. The air cleaners can also be serviced anytime, anywhere.
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I’m not chasing any performance gain by using this filter and any resultant increase would be pretty minor, but I’m chasing cleaner air and hopefully a longer life for the engine.
This airbox is much more rigid than the OE unit and won’t deform under normal and extreme off-road situations, and the way the element connects to the air inlet is far more secure and efficient than the OE flat-bed filter. Both result in much less dust getting past the filter element than in the standard situation. Combine that with the eight layers of the Fatz filter element and you’ll have less chance of dusting your engine … if you maintain the filter correctly.
AVAILABLE FROM: www.fatzfab.com.au
RRP: $740 (Fatz AirBox)
WE SAY: Requires maintenance, but lowers chance of dust bypassing the filter.
Plumbing kit for LC79/Armax snorkel: $280
Fatz Filter element: $120
CBM Prefilter: $45
K&N Cleaner Kit: $30-40