Was looking for this when eveyone was talking about K&N and some of the others here is a link to a test that was doneon some filters is a good read but sorta long.Stan

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

 

Actual data! Sweet.

 

Is anyone actually surprised with the results....?

 

Thanks Stan! Interesting tests and informative data. Shouldn't surprise us much as intuitively we should always have suspected that for approx the same area of size of filter, the greater "air" that will pass through, the larger size of dirt particles will also pass through - the tradeoff. Also, when we hang one of those 12" cone filters rated at 1000 cfm or so on a 400 or less hp engine - we're going to gain any power as we're not flowing anywhere near 1000 cfm. I haven't looked the data or tests over closley - but one interesting thing I noticed in their data was in comparing air restriction of paper filters vrs oiled filters; how the paper filter in their tests was approx linear in restriction over time as dirt accumlated on them - but the oil filter's restriction was exponential. That oil really hangs onto the dirt - but also really shuts down air flow capacity quickly.

 

already knew the K@N got dirty quick no surprise there, the K@N flows better than stock knew that too, i just dont like the fact that it says it lets dirt by, right on the K@N box it says it filters out XXX microns so can i sue K@N for false advertisement? at the end it says that increase in airflow will not help engine performance untill super modified, i call BS on that one anything alowing the engine to get air faster denser and with better flow volosity will give you dyno proven horsepower, i dont know if i believe it all

 

i think my K & N filter letting all that dirt through blew my engine


disturbing to see how much dirt the most expensive filter lets through next to a autozone special

 

too bad they didn't test any foam filters. i would be interested in that data.

 

They did...the UNI is an open celled foam filter.

 

I took way to many stats and decision sciences courses in college that made me overly critical with other peoples presentation of data.

GRAPH 1: Filter Efficiency:

Filter efficiency is a measure of the filters **OVERALL** ability to capture dirt.

The graph makes the K&N look like it is the worst thing in the world, like I may as well be using a fishing net, but the scale to the right is from 96%-100%.

So the OVERALL ability to capture dirt between the rescrictive AC-Delco and the super-terrific K&N is 3.13%.

I can be a complete retard at times, but thats how I see it...

 

In that post that Stan refers to, I said:

Air filters are not complicated devices. Ones that flow more do so at the expense of filtering capability. Like K&N says, its products filter better the more junked up they get. Why? Because until they get junked up (i.e., partially clogged), the pores are so large that a basketball can get through.

I'm not knocking any of them. But the best filtering filter is the one that came on the truck. That's why it flows less than a K&N drop-in. It's the classic performance versus reliability tradeoff."

The cited article says:

"The Flow Restriction response curves for each filter have the same basic shape. However, note how the AC Filter, which passed the smallest amount of dirt and had the highest dirt capacity and efficiency, also had the highest relative restriction to flow. The less efficient filters correspondingly had less restriction to flow. This illustrates the apparent trade-offs between optimizing a filter for dirt capturing ability and maximum airflow."

Aftermarket auto vendors are usually afraid to independently test. It's tests like these that show why.

 

That graph is a little confusing, but the way that the tests are conducted sometimes tends to compress the data. I took statistics and have studied engineering also, and I sometimes can't explain why.
Here is the bottom line:
"In 60 minutes the AC Filter accumulated 574gms of dirt and passed only 0.4gms. After only 24 minutes the K&N had accumulated 221gms of dirt but passed 7.0gms. Compared to the AC, the K&N “plugged up” nearly 3 times faster, passed 18 times more dirt and captured 37% less dirt."

 

I didn't know that, i just assumed it was another paper filter.

thanks

 

"Now I am not saying that ALL aftermarket filters are useless. A paper filter does not do well if directly wetted or muddy. It may collapse. This is why many off-road filters are foam. It is a compromise between filtering efficiency and protection from a collapsed filter. Now how many of our trucks collapse their filters from mud and water? However, if a filter is using "better airflow" as their marketing tool, remember this....Does it flow better? At very high airflow volumes, probably. BUT, Our trucks CAN'T flow that much air unless super-modified, so what is the point? The stock filter will flow MORE THAN ENOUGH AIR to give you ALL THE HORSEPOWER the engine has to give. And this remains true until the filter is dirty enough to trip the air filter life indicator. At that point performance will decline somewhat. Replace the filter and get on with it. "

 

So is this new foam filter I got from Chickenears not gonna be as great as I thought it was or what...

 

looks like itll be better than the other open air filters on the market