K&N filters

[Robes87GN]

I have a 15" K&N air filter in my 87 GN, and I was doing some reading up on it. A lot of people praise them for the added hp and air intake, but I have also read that it allows much more dirt into your engine than you normal filter will. Anyone know the actual truth behind this? If it is bad for the engine, what brand should I buy?

 

[The Radius Kid]

Bull.Enjoy the filter.They actually say that the dirtier it gets,the better it filters.
They use those filters quite extensively in a lot of forms of racing where dirt is a real problem.
That's saying something.
There are other brands of filters out there,but you'll notice that they all seem to say they're better than the K&N.
They're the benchmark,no doubt.
You've got one,use it.

 

[KillrV6]

yes there is truth behind this. a guy in our GN club did an engine oil anylisis on his chevy s10 pickup truck. he found that with the K&N filter after a certain time somthing like 5k miles, he an increase in dirt level in his oil. with a normal filter, there was not as bad of a problem. it does flow better, but just be sure to clean and re oil them often so you dont get alot of dirt in the motor.

 

[Six Banger]

FWIW, I service quite a few street motorcycles(sportbikes) with K&N filters and always see dirt in the throttle body/carb opening that has obviously gotten past the filter. Take a new oiled K&N out of the box, then hold it up to the light, look through the filter media and you will see lots of light. To me that means spaces for dirt to go through, but good for airflow. This is the reason in severely dusty conditions K&N suggests a "pre cleaner", which is oiled foam that goes around your regular filter. Oiled foam is used for motorcross bikes to this day for a reason. It flows well and traps dirt the best that I have seen. I think people (automotive) dont use it so much because of the "servicing" aspect

 

[smokin'6]

Yeah they suck
thats why every performance built GN Ive seen in 12 yrs is running one.

 

[JoeNational]

I agree with smokin i mean iam runnin a 9" k&n and couldn't be happier if you keep up with cleaning it and re-oiling it there should be no problems, the best damn air filter on the market today!!!!!!

 

[GN ERGY]

So how often should you clean and oil it?
Tarey D.

 

[d0n_3d]

HUH?!

i've been running a 9" K+N filter UNDER THE HEADLIGHT ASSEMBLY (which is about not even a foot off the ground) with a cold air kit for 3 years now daily driven in all kinds of conditions and my then stock turbo on the compressor side was very clean...the te-44 turbo i have currently was driven 10k miles and i couldn't find one single trace of dirt anywhere...including the maf pipe and maf sensor...k+n filters are THE best out there...

 

[Six Banger]

some interesting info www.unifilter.com/performance-facts.htm I guess everybody has their favorite. I am not saying one is better than the other, just what I have witnessed.

 

[KillrV6]

its not like you are gonna find a pile of dirt in your motor

its the fact that it acumulates over time in your oil and acts as an abrasive.
just clean it w/ every oil change and you will be fine.

 

[The Radius Kid]

Originally posted by Six Banger
FWIW, I service quite a few street motorcycles(sportbikes) with K&N filters and always see dirt in the throttle body/carb opening that has obviously gotten past the filter. Take a new oiled K&N out of the box, then hold it up to the light, look through the filter media and you will see lots of light. To me that means spaces for dirt to go through, but good for airflow. This is the reason in severely dusty conditions K&N suggests a "pre cleaner", which is oiled foam that goes around your regular filter. Oiled foam is used for motorcross bikes to this day for a reason. It flows well and traps dirt the best that I have seen. I think people (automotive) dont use it so much because of the "servicing" aspect

I read that little diatribe on the filters and it seems that the one thing that holds is that the more circuitous the path[labrynth effect],the better the dirt gets trapped.
Makes perfect sense.
However,to a large extent,that will also limit flow.
It's just a matter of how nasty the operating environment is that the filter has to live in.
On a motorcycle,you've got the front wheel kicking up dust almost directly at the inlet filters.
On a car,the filter is shielded behind the bumper at the very least.
No filter is perfect,if they were they wouldn't breath at all.
BTW,I've looked through all sorts of air filters at the light and I can see through all of them.
Nothing new there.
As a matter of fact,I used to check my paper filters that way.
However,your pointers on severe duty filtration are appreciated.
Maybe some of the guys on dirt roads in the sticks will take proper note.
Good info.

 

[terryk]

Correct me if I'm wrong but wasn't it GM that said by the time the K&N filter is dirty enough to filter the same as the stock filter, it flows about the same? It was worded differently but the point was the same. GM felt K&N flows better because it filtered less.

Size for size and same filtering, I don't think the K&N is any better just reusable.

I'll see if I can dig that up. Could be pure BS too.

 

[The Radius Kid]

Originally posted by terryk
Correct me if I'm wrong but wasn't it GM that said by the time the K&N filter is dirty enough to filter the same as the stock filter, it flows about the same? It was worded differently but the point was the same. GM felt K&N flows better because it filtered less.

Size for size and same filtering, I don't think the K&N is any better just reusable.

I'll see if I can dig that up. Could be pure BS too.

According to Chuck Leeper who contacted K&N about the airflow capabilities of their 9" filter,it will flow enough to support 900 h/p.
That may be optomistic,but do you think the stock air filter for a G/N can flow anywhere close to that?

 

[shawnz]

So if you dont have access to the kn cleaner kit what else can you use to clean the filter and oil it

 

[terryk]

Originally posted by The Radius Kid
According to Chuck Leeper who contacted K&N about the airflow capabilities of their 9" filter,it will flow enough to support 900 h/p.
That may be optomistic,but do you think the stock air filter for a G/N can flow anywhere close to that?

Are you talking about the stock replacement size filter for the GN? I'm just talking the same size filters. I certainly expect my 14" cone to flow more than the stock GM GN filter.

 

[The Radius Kid]

No,I specifically said 9".That's what most guys replace their stock filters with.
However,I do have a friend up here that replaced his stocker with the K&N stock replacement and he felt a bit of an improvement .

 

[Chuck Leeper]

Filter requirements

I had forwarded the K&N calculations to Ken Mosher for inclusion in the GNTTYPE tech archives.
As I recall, all the mfgrs that use gause materials for filter medium, use the same formulae..
If it's not there, I'll post it.

 

[terryk]

Originally posted by The Radius Kid
No,I specifically said 9".That's what most guys replace their stock filters with.
However,I do have a friend up here that replaced his stocker with the K&N stock replacement and he felt a bit of an improvement .

I get it now. No I don't.

 

[smokin'6]

Originally posted by shawnz
So if you dont have access to the kn cleaner kit what else can you use to clean the filter and oil it

Autozone sells the kit, as well as johnsperformance.com