How to compare different air filter design efficiencies

[sciguyjim]

Hi all, I need some suggestions, guesses even. I'm thinking about making a custom air filter for my car that I want to flow well, of course, but also have better filtering efficiency than some other filters on the market. I'd like to find a way to compare the airflow through each design, and also compare the amount of fine dirt trapped. Unfortunately I have no flow measuring equipment, no microscope to take good looks at the filters, and no artificial dust of known micron sizes. I refuse to throw handfuls of dust at my filters to simulate a year's worth of driving just to compare the trapped material. The best idea I've come up with so far is to somehow make an airtight connection betwen each filter design and my vacuum cleaner. Unfortunately I have no way to compare airflow or filter efficiency and I'd probably have to use fine, dusty dirt as my test dust. I can make crude comparisons of filter colors to judge dirt trapped, and look at what dust made it through the filter and into the vacuum cleaner's regular dust bag. Any suggestions??? Thanks.

 

[GregLocock]

Weigh the dried filter system before and after filtering a set amount dirt.

Use a water filled U tube to measure the pressure across it .

Cheers

Greg Locock

 

[sciguyjim]

I can try and rig up some kind of big U-tube and hope my vacuum cleaner doesn't suck up any water. Unfortunately I don't have any means of weighing the filters either. (I also thought of weighing the filter bag that goes inside the vacuum cleaner too. I could make a lever out of a meter stick and use it as a balance.) Basically I have nothing to work with. It would be nice if I worked somewhere where I could borrow their equipment but I'm unemployed at the moment and I'm doing this at home. Some filters I want to compare are oil coated. About all I have the capability of doing is rinsing the oil+dust off and filtering the dust out then visually examining the filter paper. Rinsing wouldn't remove all the dust from a paper filter though. I can't even be sure I'd expose each filter to the same dusty conditions. This is looking like it's beyond my ability to do. Maybe the results will be obvious enough to rate the filters visually (my fingers are crossed.) Not working for a nice big company with lots of equipment is very frustrating.

 

[Chumley]

Why not use an OEM approved air filter of a given area or larger based on an existing engine hp/displacement/CFM rating and change interval. The OEM filters will have all ready passed the standard SAE J-726 filtration test. In effect, if you go OEM, all the testing has all ready been done for you and all you have to do is pick an appropriate size filter for your application. And please, let's not even mention "X & Z High Performance Filters" in this discussion because those filters can't meet all the OEM specs. That's why they aren't specified for OEM applications.

Chumley

 

[sciguyjim]

I may end up just using a standard OEM filter, it's just that I like to experiment and I think I can do better than some existing, supposedly very good, filters. I don't plan on buying a bunch of different brands and running my own comparisons, I'm not that interested in this. I just have some ideas I'd like to try and I'd like to have the peace of mind that comes with knowing my filter is doing a good job rather than a bad job and is not ruining my engine. If I can't be assured of that I probably won't continue the experiment.

 

[tannguyen]

If you have a VW or Audi, you can get readings off of the OBDII computer, directly from the MAF sensor, if you have a VAG-COM.