ORIGINAL: kenv

ORIGINAL: timinbovey

Actually, I had somewhat similar thoughts.
I just purchased a new 4.0 Mustang, and as usual am looking for some performance upgrades, AND I'm VERY **** about using only what I can find and prove is BEST for the machine, not what is advertised as good, what anectodal stories point to as being the best, or what seems to be popular. I want hard facts.

That said, I am having a hard time convincing myself to go with a K&N filter. I can be convinced that the better airflow can (however little) be an improvement in performance, mileage, HP, etc. But..at what cost to engine life? While I do NOT believe that use of an oiled filter will ruin anything if you oil it right, how can it possibly be considered a good thing to cover a car part in sticky oil and shove it in your intake? It's a mess no matter how you look at it. But, what really concerens me is....EVERY documented test I can find, both on the internet and in trade publications shows that the gauze/oiled style filters allow the MOST DIRT into an engine compared to even inexpensive paper filters from the discount stores. So, you're getting some increased flow, but with greatly reduced filtration. I'm sure K&N and others would be fast to dispute this, but there is NO information on their website showing actual filtration ability, specifics, etc. Nothing there to compare the ability of their product to FILTER THE AIR compared to their competitors. Just that they increase flow, last long, and can be cleaned, reoiled, reused. I really don't care about increased flow and a filter that lasts forever, if it's letting ANY increased amount of contaminants into my engine! Which also makes me wonder about all the cold air intake systems from various sources. I do believe that you can see an increase in HP with these, but NONE of them seem to offer ANY information about actual filtering ability in reference to what gets thru them. So, pick up a few easy HP at the cost of sucking more dirt into the engine? That's not for me.

I didn't read every post in this thread as it turned pretty quick into a bashing the bashers list. And I know there are those that seem to hate Amsoil and it's fans. However, the ONLY test information I've been able to find on actual filtering ability was on their web site at:
http://www.amsoil.com/StoreFront/eaa.aspx
Unfortunatly, Amsoil does not presently offer a filter for the 05-07 Mustangs, or, if they do, it's not listed on their product guide on their web site. And an e-mail to them about such a filter indicated it wasn't available yet. My e-mail to K&N about filtration ability and specifications was answered with advertising rhetoric and no hard facts.

Far as I'm concerned, the number ONE job of an air filter is to keep dirt, dust, etc OUT of my engine, and any way that increases airflow while maintaining at LEAST the filtering ability of the OEM filter is all the better. Every test I can find shows the wet gauze type filters let the most dirt thru, while increasing airflow.

And as a footnote, if you want to add easy HP, switch to a synthetic oil. I fully, completely, and 100% believe that Amsoil is the best synthetic out there, and you can all decide for yourselves, just be sure you do your research by reading actual LAB results, not stories and advertisements. I actually witnessed nothing more than an OIL CHANGE from a dino 10W-40 to Amsoil 10W-40 increasing RWHP on a dyno by 8 HP. This was in a big block Ford many years ago. The amount of increase that you can expect varies mostly with engine size. The increase is bigger in larger motors, simply because the increase is caused by reducing internal friction and of course there is more friction area in a larger motor, so the increase is more dramatic. Back in the 70's and early 80's when I was hot rodding Fords that were not computerized and fuel injected, etc. so they had no automatic engine controls, it was not uncommon to have to physically adjust the idle speeds down because I'd pick up 50 - 100 RPM just by changing to Amsoil.

But, as I say, belive what you want. Try to study actual test papers not ads. I have yet to find any test that indicated wet oiled filters filter as good as even cheap cellulose (paper) filters. They hold more dirt, but it's bigger dirt. Not for me!

Tim in Bovey

ORIGINAL: Gene K

K&N says their filters are designed to be 98% efficient.
Donaldson (one of the best paper filters) based on Freightliner Tests is 99.6% efficient.

According to K&N their filter passes 5 times the dirt of a Donaldson (Paper).

That said how much is to much? Will the 5x increase be enough to significantly shorten engine life? I really dont know.

I do know many of the things we do to increase engine performance shorten engine life. Each has to choose which trade offs he is willing to make.