Proof that K&N sucks at filtering air
 

Years ago when I opened my Ninja 600 motors running K&N filter, I saw alot of dirt in the carbs and cylinder heads. Always thought that this wasn't good.

Here is proof:

Debunking the K&N Myth - Why OEM is Better : Nissan Articles

For me, I don't have much choice as I'm running the ASP large IC and therefore cannot run the stock airbox.

I prefer OEM over a lot of things whenever I have the chance. The amount of money that is spent on engineering and designing parts that just work is a lot greater than aftermarket companies usually. Of course there are areas where aftermarket parts do work better, since OEM parts are designed/geared more for general masses.

Makes me want to get creative in which filter to use.

They don't filter well and I try not to use them. I do use them on the FD but not by choice. I use OEM if possible. Take a dab of grease and put it inside the intake tube after the filter and drive around for a couple weeks then check the grease drop, gritty.

Benzworld.org - Mercedes-Benz Discussion Forum - View Single Post - Do K&N filters really damage MAF sensors???

Hmm interesting, I'm using an K&N Drop In Filter.

Unfortunately, K&N is really the only option for most of us. Their giant catalog of filter sizes and the fact they have a virtual monopoly on the filter market means you're pretty much hosed.

Yeah, stock airbox can let you run a paper element, but that isn't an option if you start modifying your car, that space is needed for an intercooler or intercooler pipes. Not to mention the stock airbox is a PAIN in the ASS.

Having the filters in the engine bay and not down at road level is also a big help - typically on the FD you have them in the engine bay, not as a cold air intake like many cars do.

The big thing here is this is a LAB TEST. While that has many good numbers, what's the real-world impact? Does this mean your engine will eat x particles of dust and will degrade the life of the engine by y? Will you break an apex seal or kill a water seal long before you actually get to the wear problems of the extra dust in the engine?

Dale

On the subject of air filters:

I did oil analysis over 40k miles on my Protege5 which showed that the K&N cone let dirt in, resulting in high Silicon reading and bearing wear; yes it was well maintained.

After reading up on bobistheoilguy forum, finally found the Amsoil 'ea' line of filters. They are excellent and cleaned up the car's oil analysis. Availabile in a lot of the sizes that K&N makes. They just don't market them very well.

AMSOIL AMSOIL Ea Universal Air Induction Filters

No I do not sell them ;)

I'm pretty sure that test was with the oiled type of filters. Their dryflow filters are much superior. They make them for AEM as well.

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Is this really news?

I would think most people know that swapping out the factory intake system reduces your air cleaning capability for the sake of more performance, just like turning up the boost reduces turbocharger life for the sake of more performance.

:icon_tup::lol:

Who cares? Nobody suffers engine failure in an FD because of this. I'm keeping mine.

Sorry for offtop, guys. But what do you think about Blitz Advanced?

Sure. But it would seem like additional dirt through the motor wears everything faster. So when you do break an apex seal, there could easily be even more stuff to replace.

I am running a truck filter S&B filter.

... It's worse than that...

Not sure you’re really get more "power" K&N is claim is more flow over a dirty paper filter .. I just finished a lot of dyno work and tuning on my Lotus, we got to test baseline new OEM filter to new K&N panel filter on a exhaust and tune modified car and saw zero power change. Unfortunately, I was also developing a high flow cold air intake and this did require cone filters, the compromize we all end up with, but for that we ended up using ITG foam filters.

I don't think it's fair to say they "suck".

coarser element = less filtering = less restriction = more flow = potential for more power
finer element = more filtering = more restriction = less air flow = potential for less power

Like everything, there are trade-offs. I don't see this as justification to say they "suck". There is no holy grail of air filters (i.e. one that will offer maximum air flow AND maximum particle filtering) - the trick is to pick one that is best suited for the application.

we run a dry AEM on the race car, and the inside of the intake tube gets dusty.

Does anyone know of a replacement for the K&N filter commonly found in CAIs for the RX7 (cylinder with 2.5" inlet, 3.5" OD, and 6" length)?

I agree the K&N doesn't filter very effectively, and I've found this is especially critical for the RX7. Both the boxed M2-style cold-air-intakes and the open-style intake pull air from low to the ground where a lot of dust and crap is thrown up, and neither affords the high intake location, baffling and convolutions most stock air pathways used to keep or drop particulates out of the airflow before it ever gets to the filter. As a result, these K&N's get hammered by a lot of crap, and they aren't really designed to take it. Which is going to mean more engine wear. How much more - well, lets face it, nobody on this forum has the money, time, skill and test equipment to tell us, so of course its an excellent topic to debate! But we can all agree extra dirt in the engine can't be good.

And there doesn't seem to be a good paper or dry filter replacement for the K&N filter we typically use in aftermarket cold air intakes. AEM, etc don't seem to make anything with a 2.5" inlet, 3.5" OD and 6" length like the K&N RB-0720 we typically use:

RB-0720 - K&N Universal Air Filters, Universal Rubber Filter direct from K&N

If someone finds something, please post it.

So to get as much filtering as I can out of the K&N's, I just purchased the K&N filter wrap that can be used with this filter. I'm hoping it will conform to the space available, since it is foam.

25-1770 - K&N Filter Wraps, Air Filter Foam Wrap direct from K&N

Another option might be the generic filter wrap K&N also sells, which would be less since it can be cut to shape, but would need to be tie-wrapped carefully to avoid any leaks:

25-3900 - K&N Filter Wraps, Air Filter Foam Wrap direct from K&N

That bulletin came out in 1995. There was very little development in the aftermarket place for the FD at the time. However, their "claim" was the hot air, not dirty air was killing the airpumps.

Thats just wrong. Since the intake under the car is forward of any dust that may be created by the front tires, the air pulled from under the car isnt going to be any different than the air one foot above the ground (where the stock intake opening is) in front of the car.

In addition to that, I dont believe that many of us drive our FDs on dirt roads, so dust under the car isnt really an issue.

Sorry to disagree Adam, I've used your cheap bastard intake with the stock K&N and hole cut in the bottom of the stock airbox (and was very happy with it), I've used the M2 CAI, and right now I've got an open intake with the K&N cylinder intakes. All got a large amount of grit and crap in the airbox and on the filter that you don't see with the stock intake system. This is experience, not speculation.

The cheap bastard intake is a great solution, because you can use a finer, paper stock filter and replace it often.

Both the cheap bastard and the M2 pull air from the bottom of the car, right from the roadway. Which isn't clean air.

You don't drive on dirt roads. Awesome. You do drive in traffic, behind other cars? Tires on cars in front of yours are kicking up dust.