Sizing your air filter

[PeeBee]

Guys, I have been working through the process of selecting a suitable air filter for my new engine and came across this excellent tool from Donaldson. In summary, all you need to know is the size of your engine in litres, the rpm you want to check it for, say at the redline, then the Volumetric Efficiency of the engine, which is given for you in the table and you can calculate the actual m3/min of air you need to handle. from there its a simple task to contact the supplier of the filter and get the air volume the filter is designed to handle, and bingo, you can see how conservative or borderline your filter is. A worked example is below, for my engine.

1) The K&N filter I have selected is designed to handle 40m3/min of air.

2) Eng size = 6.5L

3) Engine speed max, = 3200rpm

4) VE = approx 1.7

Engine Volumetric demand on filter = 6.5 x 3200 x 1.7/2000 = 17.68m3/min

So, 40m3/min /17.68m3/min = 2.26 which is my service factor for the selected filter. This tells me i have a fairly reasonable selection and my face velocity will be within limits for dust filtering. If you know the area of the filter you could then calculate that face velocity and refer to additional charts for a different service factor. I am trying to get that value now and will update the selection process. Bear in mind, if you dont drive to the redline, and most of us rarely do, then the service factor or duty on the filter gets even better. the idea behind having as high a service factor as practical is to give you a good margin of safety when you get into the dusty stuff and ensure your engine is not sucking dust through the filter media because its too small an area for the volume.

[mudski]

Speaking of Donaldson. As I work for a Donaldson and Fleetguard dealer I have direct access to their products. I was only thinking of this today too. Donaldson have designed a new housing assembly, well quite a while ago but still fairly new. Called Powercore. A more compact housing but it allows for higher air flow whilst still retaining optimum filtration. If you ever need any Donaldson, or Fleetguard products Phil. Let me know.

[PeeBee]

Speaking of Donaldson. As I work for a Donaldson and Fleetguard dealer I have direct access to their products. I was only thinking of this today too. Donaldson have designed a new housing assembly, well quite a while ago but still fairly new. Called Powercore. A more compact housing but it allows for higher air flow whilst still retaining optimum filtration. If you ever need any Donaldson, or Fleetguard products Phil. Let me know.

OK, will do. The filter I am looking at is the K&N 0880, which is 150 dia x 425 long - big sucker! I am looking at the Fuel Manager range of fuel filters that have containment and water separation capabilities, and are sold by Western Filters using a fuel manager filter , one with a 30um and one with probably a 6um filter- unsure of you have an equivalent? I am currently looking for something in the range of 300 - 400lphr capacity - subject to confirmation by friday, so keen to hear whats out there.

[PeeBee]

Speaking of Donaldson. As I work for a Donaldson and Fleetguard dealer I have direct access to their products. I was only thinking of this today too. Donaldson have designed a new housing assembly, well quite a while ago but still fairly new. Called Powercore. A more compact housing but it allows for higher air flow whilst still retaining optimum filtration. If you ever need any Donaldson, or Fleetguard products Phil. Let me know.

PM sent Mark

[mudski]

OK, will do. The filter I am looking at is the K&N 0880, which is 150 dia x 425 long - big sucker! I am looking at the Fuel Manager range of fuel filters that have containment and water separation capabilities, and are sold by Western Filters using a fuel manager filter , one with a 30um and one with probably a 6um filter- unsure of you have an equivalent? I am currently looking for something in the range of 300 - 400lphr capacity - subject to confirmation by friday, so keen to hear whats out there.

http://www.donaldsontoolbox.com.au/files/4013/4830/4308/12EPP004_P903074_Diesel_Fuel_Kit_Chassis_Mount.pdf

This is a pretty popular kit Phil. But quite large in dimensions. Why are you looking for such a large fuel capacity? Wouldn't have thought the 6.5 would need such a high flow rate.

We sell a few of these too...
http://www.donaldson4wd.com.au/files/4914/2404/6594/11EPP002_P902976_Diesel_Fuel_Kit_brochure_10-13.pdf

[PeeBee]

http://www.donaldsontoolbox.com.au/files/4013/4830/4308/12EPP004_P903074_Diesel_Fuel_Kit_Chassis_Mount.pdf

This is a pretty popular kit Phil. But quite large in dimensions. Why are you looking for such a large fuel capacity? Wouldn't have thought the 6.5 would need such a high flow rate.

We sell a few of these too...
http://www.donaldson4wd.com.au/files/4914/2404/6594/11EPP002_P902976_Diesel_Fuel_Kit_brochure_10-13.pdf

Still waiting on the fuel pump WOT tests that are happening today. The over supply is pretty common - based on my flowmeter I see around the 85% over supply at idle which decreases as the demand comes on. The focus is to try and maintain a net positive pressure at the inlet to the injector pump so you don't generate any vacuum vapour that alters the calorific value of the fuel and also affects the injection system - depends on how detailed you want to get I suppose, but I would be happy with a nett pressure of +1PSI above demand at WOT, bearing in mind I rarely drive like that.

[mudski]

Still waiting on the fuel pump WOT tests that are happening today. The over supply is pretty common - based on my flowmeter I see around the 85% over supply at idle which decreases as the demand comes on. The focus is to try and maintain a net positive pressure at the inlet to the injector pump so you don't generate any vacuum vapour that alters the calorific value of the fuel and also affects the injection system - depends on how detailed you want to get I suppose, but I would be happy with a nett pressure of +1PSI above demand at WOT, bearing in mind I rarely drive like that.

Gee you have really put some thought into it... Do you have an external lift pump fitted near the tank?

[PeeBee]

Gee you have really put some thought into it... Do you have an external lift pump fitted near the tank?

Waiting on the pump test today, then will select the lift pump. Right now my lift pump runs at 60lphr at 8psi(nameplate). At WOT the engine is using 52lphr but actual fuel pressure drops to zero, so the injector pump is effectively drawing from the tank direct. The literature I have read when reviewing the filters and lift pump from Poindexter all suggest a net positive pressure to the injector pump is the way to go. My existing lift pump is mounted on the chassis rails under the drivers seat. I think this is too far from the tanks and should be way down the back so the length of pipe from the lift pump to the tank is low - pump will deliver better if relocated as they typically are better on discharge head than suction head. For this reason the filter needs to be compact but still rated for the flow to the injector pump as defined by the lift pump. There is a simple Aeroflo pump rated at 400l[hr and 14psi which I think will do the job, and I know it is working on a truck fitted with the same S/C I will be getting and has the 18psi pulley, and its less than $100, or if that's not enough, the next option on my radar has an adjustable pump up to 75psi and 400lphr, but its approx. $500-600, so leaning towards the simpler pump and can afford to hold a spare in hand as well.

[mudski]

You obviously have a fuel pressure gauge inline somewhere. I've was keen on running a temporary gauge in mine just to see what goes on in the fuel pressure department.

[PeeBee]

Yes, bought a digital one from NZ, cost about $150 from memory, just tees into the supply line. Also have the flow meters on supply and return line to show total used, instant flowrate and total distance to empty based on fuel rate consumed.

[mudski]

Yes, bought a digital one from NZ, cost about $150 from memory, just tees into the supply line. Also have the flow meters on supply and return line to show total used, instant flowrate and total distance to empty based on fuel rate consumed.

Im just imagining what your dash looks like with all the gauges...
77178

[PeeBee]

Yes, its getting busy!!!

[Rossco]

Actually thought that was Phil's car until closer inspection [emoji6] . . .

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