K&N Air Filter Review - Debunking the Myths (and why OEM is better)

 

That's def interesting, although when was this test performed? I didn't notice the amsoil Ea style filter just the old ts style

 

Not sure.

It was a good read though. I found this article while looking up information on factory oem AC Delco filters.

 

Remember back when a K&N Filter was a instant 30 hp. What a joke. They made millions off of selling that crap to the masses. I was guilty back in my younger days.

 

I'm still a little confused...if I'm reading this right the OEM filters are "better" for engines without heavy mods because they do not clog up as fast and don't pass nearly as much dirt as the washable less restrictive filters?

So pretty much for the K&N to be worth anything, it has to constantly be cleaned? You still run the risk of passing more dirt than a stock filter but the trade off is more airflow provided that the filter is maintained correctly

 

Thats how I took it.

 

yea so for us guys that are actually pulling and pushing more air than stock still probably need a k&n IMO, especially considering where our filters are. i guess running a prefilter or hydroshield should be standard

because most guys running a simple stg2 setup alone are pushing 5-7 psi over stock. and idk what CFM difference is but its gotta be a lot haha

nice article

 

Not really. GM tested the build book engine with the oem filter. The guys really pushing these cars no doubt benefit from aftermarket high flow filters, but for most, the oem filter should not cause too much restriction.

I currently run the stock filter in my modded box, and I noticed no difference from the K&N drop in. Just like all the intakes I tested made no big changes other than whine. Powell runs the oem filter on his TVS redline with 300+ whp.

I'm going to test the blower inlet pressure through out the rpm band this spring, to see if the oem filter is causing any restriction. I have some logs with the k&n already for comparison.

Yup, but oem intakes / filters are starting to become less and less restrictive on newer cars. That's why we dont see those crazy "claimed gains" anymore.

 

interesting

well i guess i'd have to find an acdelco filter to run on my 3" intake if i wanted to make the switch

 

I'd be interested to see how the new amsoil Ea's perform since they're based off Donaldson Torrit's baghouse filters which require fine particle filtration. Granted a bag house is a lot different than a car, the less time blowing down longer the filters/bags last

 

Awesome thread Jeff

 

Thanks man

 

Good read thanks
In to see numbers on our cars

 

Below is a good take from the article:

"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 engines 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 be recognizeable. At that point performance will decline somewhat. Replace the filter and get on with it."

 

I'm guessing heavy head work is the only reason why you'll need anything other than stock?

 

It would be nice to do a little test on a high powered TVS or turbo car to see how much restriction an oem filter may cause.

Bill Duncan always told me the LSJ responds much better to modifications on the exhaust side vs. the intake side.

I'd have to say he has been correct. Other than my H62 blower, my exhaust modifications have provided the most noticeble gains, ie. full exhaust and exhaust ported head.

 

Do you know how many lbs of air you're pulling in? You can covert that to cfm for a given temp and relative humidity to see if we even flow 350cfm

 

Before the ported head, I was flowing close to 40 lbs/min.

I havent run any tests with the ported head yet.

 

Now you got me thinking.

Although I remember distinctly the car had much better throttle response once k&n was installed

 

lol/ I posted this info on another site. Incredibly, folks jumped in and commented without reading.

its a crazy world. If you still run K&N after reading this, you sure drank the Koolaid... and btw, 100% of the folks who show up at my shop with K&N (90 % of the folks who come by) have horribly dirty filters.

"It’s important to note the different test durations for each filter. The AC Delco filter test ran for 60 minutes before exceeding the restriction limit while the AMSOIL and K&N tests each ran for 20 and 24 minutes respectively before reaching max restriction.

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. See the data tables for a complete summary of these comparisons."

Hows that " much better throttle response" after a few weeks?

 

Thank you for posting this John.

 

I have always stuck with a stock A/C Delco or Fram, never believed the K&N hp boost claims. If that was true, GM would stick them in new vehicles for an instant 30 hp boost.

 

how long is the ac delco filter good for?

i went to a k&n because it was reusable, but i am definitely reconsidering running a stock filter

thanks for posting this

 

Depending on the driving conditions, I usually change mine out every three oil changes (about 10K). I take a sharpie and write my mileage on the filter to keep track. I'll stock up on a few when I find them on sale.

 

It's an old test, but a good one, but the premise of the test isnt for performance. It's for filtration capacity and essential the "time to restriction". Pointing out that the OEM filter not only provided the best filtration but the longest usable lifespan. Alot of this has to do with the material being used, but given the fact that its a much older test, it doesnt take into account new filtration styles such as the AEM dry flow filters which were in fact designed by K&N which really are probably far superior to any aftermarket filter that was available at the time that test was done.