New K&N filter or not?

[thescreensavers]

Given the importance of the oil filter and the extremely low cost of producing even a good one it seems safe to think that if the OEM ones were inferior the manufacturer would spend a few bucks making a better one, thus reducing engine problems.

In short, beyond the fact that many people quantitatively believe K&N is not good, logically I see no reason to use them; go with an OEM filter. What exactly do you think this K&N is doing for you that the factory-spec filter specifically made for that engine cannot do?

we are talking about Air Filters 😛, K&N Oil Filters are actually very good.

 

[Pacfanweb]

That's how they allow for "improved performance" Less restrictive intake equals easier breathing engine equals more power.

No, it doesn't, unless your stock filter is restricting airflow to your engine....which no stock filter does.

All cars come with a filter that can flow FAR more air than their engine can ever use in stock or even mildly modified form.

Adding a filter that can 'theoretically' flow more helps NOTHING. When you combine that with the fact that K&N's (and all other filters like them) allow a LOT more dirt through, PLUS they cost much more PLUS they require maintenance other than just throwing them away....they are near the top of the snake oil list.

K&N filter: 40 bucks or so for a drop-in.
"Recharge kit": Another 10-20 bucks.

How many stock filters can you buy for 50-60 bucks? You'd have to drive WELL over 100k miles to even come close to breaking even on the cost aspect.

 

[Gillbot]

No, it doesn't, unless your stock filter is restricting airflow to your engine....which no stock filter does.

All cars come with a filter that can flow FAR more air than their engine can ever use in stock or even mildly modified form.

Adding a filter that can 'theoretically' flow more helps NOTHING. When you combine that with the fact that K&N's (and all other filters like them) allow a LOT more dirt through, PLUS they cost much more PLUS they require maintenance other than just throwing them away....they are near the top of the snake oil list.

K&N filter: 40 bucks or so for a drop-in.
"Recharge kit": Another 10-20 bucks.

How many stock filters can you buy for 50-60 bucks? You'd have to drive WELL over 100k miles to even come close to breaking even on the cost aspect.

You might want to check out many of the reviews posted here in the garage on the K&N, you can clearly see that the "increase" is in fact gained by decreased filtering capacity.

It is also known that a simple CAI upgrade will yield a small increase in power on MANY cars so that pokes another hole in your theory.

 

[slag]

k&n sucks - the oils will mess up a lot of maf sensors - just stick with a dry filter

Over-oiled k & n filters may mess up a maf sensor, but then you did that to yourself. I ran one with a cold air intake(re: outside the engine compartment) on my 97 gtp and liked it.. never had any problems with it.

 

[Gillbot]

Over-oiled k & n filters may mess up a maf sensor, but then you did that to yourself. I ran one with a cold air intake(re: outside the engine compartment) on my 97 gtp and liked it.. never had any problems with it.

I had an issue with my maf from an "out of the box" new K&N. It's actually a fairly common issue.

Bottom line is, there are two ways to increase airflow. Larger filter or less filtration. Given the restrictions on the stock airbox size, the most common way is to decrease filtration.

 

[Pacfanweb]

You might want to check out many of the reviews posted here in the garage on the K&N, you can clearly see that the "increase" is in fact gained by decreased filtering capacity.

It is also known that a simple CAI upgrade will yield a small increase in power on MANY cars so that pokes another hole in your theory.

Nothing you said pokes a hole in my FACTS.

First off, I talked ONLY about drop-in filters.

Second, a CAI has absolutely nothing to do with a K&N filter, which is the subject here. You can just as easily put a paper or and AEM on a CAI and get the same results.

You are correct in that the extra flow a K&N attains is by reducing filtering capacity, but that's not the point, either. If the engine doesn't NEED the extras capacity, you can put a filter the size of the hood on it and it won't have anymore power.

A CAI changes the route the air takes. THAT can help, in some cases, but that has nothing to do with the filter that's attached to it.

 

[Gillbot]

Nothing you said pokes a hole in my FACTS.

First off, I talked ONLY about drop-in filters.

Second, a CAI has absolutely nothing to do with a K&N filter, which is the subject here. You can just as easily put a paper or and AEM on a CAI and get the same results.

You are correct in that the extra flow a K&N attains is by reducing filtering capacity, but that's not the point, either. If the engine doesn't NEED the extras capacity, you can put a filter the size of the hood on it and it won't have anymore power.

A CAI changes the route the air takes. THAT can help, in some cases, but that has nothing to do with the filter that's attached to it.

Not always, many CAI's use the stock locaton and route, they just give you the option of a larger filter.

 

[drnickriviera]

No, it doesn't, unless your stock filter is restricting airflow to your engine....which no stock filter does.

All cars come with a filter that can flow FAR more air than their engine can ever use in stock or even mildly modified form.

Adding a filter that can 'theoretically' flow more helps NOTHING. .

So you're saying a stock filter provides no restriction at all? Why don't race cars use them if there is no restriction?

 

[NuroMancer]

Nothing you said pokes a hole in my FACTS.

First off, I talked ONLY about drop-in filters.

Second, a CAI has absolutely nothing to do with a K&N filter, which is the subject here. You can just as easily put a paper or and AEM on a CAI and get the same results.

You are correct in that the extra flow a K&N attains is by reducing filtering capacity, but that's not the point, either. If the engine doesn't NEED the extras capacity, you can put a filter the size of the hood on it and it won't have anymore power.

A CAI changes the route the air takes. THAT can help, in some cases, but that has nothing to do with the filter that's attached to it.

It was my understanding that a CAI is to reduce the air flow restriction pre-filter and at the filter.

If you have capacity at the filter, and behind it, but the original intake is restricted it doesn't matter what type of filter you put in there as long as it pass more air then the original restriction point. But if the filter was designed for the air flow of the original system, then would need something that would allow more air flow.

CAI don't always "change" the route the air takes either.

 

[Arkaign]

Heh, Pacfan is sure adamant about hating these things, to the point of making no sense at all.

The truth, as usual, is somewhere in the middle of the extremists on both sides. I will agree that for most vehicles a K&N drop-in isn't going to make an appreciable difference, and there is also truth that it will be less effective at filtration duties and can be risky on certain configurations regarding MAP/MAF components. OTOH, there are a number of vehicles, in particular high-revving DOHC motors, which add dyno-proven power to a small but measurable and repeatable degree. Worth it? That really depends on the owner of the vehicle, it's just another choice out there amongst others. No need to go bananas over it.

 

[Pacfanweb]

So you're saying a stock filter provides no restriction at all? Why don't race cars use them if there is no restriction?

Um, you might want to what I've written again.

I said for a "stock to mildly modified" engine, a stock air filter flowed more than enough. And I'm correct.


Last time I checked, RACE engines aren't STOCK or even "mildly modified".

And ask any race engine builder, and he'll tell you he knows just from the engine tear-down and inspection who runs a K&N filter, just from the wear.

 

[Pacfanweb]

It was my understanding that a CAI is to reduce the air flow restriction pre-filter and at the filter.

If you have capacity at the filter, and behind it, but the original intake is restricted it doesn't matter what type of filter you put in there as long as it pass more air then the original restriction point. But if the filter was designed for the air flow of the original system, then would need something that would allow more air flow.

CAI don't always "change" the route the air takes either.

"pre-filter"? I think you might mean "post filter".

A CAI is to reduce restriction, period. It has the feature of allowing a different (usually conical) filter at the end. Really, no different than changing the intake manifold on a carbureted vehicle.

It's designed to allow the engine to suck in more air. Trouble is, a stock engine can't take but so much more. The stock air filter already flows more air than the engine could ever use, regardless of the tube that connects it.

So will a CAI with a K&N on it likely increase your power? Probably. But so with a CAI with a paper filter. And that one won't clog up your MAF.

There's a reason that every car manufacturer has TSB's on K&N's causing these types of problems.

 

[Pacfanweb]

Heh, Pacfan is sure adamant about hating these things, to the point of making no sense at all.

No offense, but I've made perfect sense here, not my fault you don't understand it. 😉

I don't "hate" K&N's, but I do like to come on strong against things that people spend a lot of money on that don't return the value. Get me started about those ridiculous Tornado things that they want you to plug up your intake with.

 

[Gillbot]

Um, you might want to what I've written again.

I said for a "stock to mildly modified" engine, a stock air filter flowed more than enough. And I'm correct.


Last time I checked, RACE engines aren't STOCK or even "mildly modified".

And ask any race engine builder, and he'll tell you he knows just from the engine tear-down and inspection who runs a K&N filter, just from the wear.

Then show us evidence of all these aftermarket filters NOT gaining any power by reducing filtering capacity and increasing flow, just by replacing the stock paper filter.

 

[Pacfanweb]

Then show us evidence of all these aftermarket filters NOT gaining any power by reducing filtering capacity and increasing flow, just by replacing the stock paper filter.

http://www.bobistheoilguy.com/airfilter/airtest2.htm

So what do these results mean? For one, there is very little pressure drop across any air filter, and the difference between the best (K&N) and worst (paper) is very small. Yes as total power output increases, air flow increases, and differential pressure would also increase. So a K&N probably does yield some power on higher output race motors where every last ounce of power must be squeezed out. On lower powered street cars, it is probably not much of an improvement over paper.

Pretty much what I've said.

http://www.eilenberger.net/R1100R/

If there was any difference caused by the K&N it was not measureable on the dyno - the three runs are as close as I've ever seen, and the difference is less than the error of margin for the dyno runs. Conclusion: K&N is yet again not doing anything good for the bike.

http://www.jackphelps.com/frontier/dynoknfilter.htm

The two runs with the K&N filter were almost identical, so I believe that they were as accurate as we would get. When compared with the stock runs they showed almost no difference in either horsepower or torque. As you can see from looking at the graphs below, the readings were incredibly similar; any differences were so small that they would be statistically insignificant.

Again, on stock or pretty-much-stock engines, the stock air filter already flows more than the engine needs or can draw through the stock air tube.
Pretty much everyone in the car business knows this.

When you add in that they clog up 3 times faster, let FAR more dirt in, and cause problems with the MAF's, they just aren't worth it.

I'd recommend an AEM dry filter in a heartbeat over a K&N, if you just don't want the stock one anymore.

Start increasing power a lot, and of course a bigger filter will be needed, but K&N isn't the only place that makes larger filters that flow more.

 

[Gillbot]

A bench test does NOT equate to real world results.

EDIT: and for the record, I run a paper filter on my RACE motor so i'm not biased for K&N. I highly prefer the paper filter, but most cars do see a slight gain when going to an aftermarket filter.

 

[Pacfanweb]

A bench test does NOT equate to real world results.

EDIT: and for the record, I run a paper filter on my RACE motor so i'm not biased for K&N. I highly prefer the paper filter, but most cars do see a slight gain when going to an aftermarket filter.

Um, you asked:

Then show us evidence of all these aftermarket filters NOT gaining any power by reducing filtering capacity and increasing flow, just by replacing the stock paper filter.

And I gave you some evidence of exactly what you asked for. Then you change the criteria?

"real world results" cannot be measured, in the very minute amounts we're talking here.

How can a dyno test not equal 'real world results'? That's a 'real world' as it gets....a test on an actual vehicle, not a flowbench.

Unless you gain a LOT of power, you can't feel it. And by a "lot", I'm talking 20hp or more. You cannot feel 5hp, and on anyone other than K&N's own tests, a simple drop-in filter does not, and cannot make that much difference.

Any 1-2-3-5hp gain you 'think' you can feel in the 'real world', is imaginary.

Oh, just so we're on the same page, I'm talking about a drop-in K&N with everything else stock. No CAI. Although I still say that even on a CAI, which CAN make some more power, you won't see anymore power with a correctly-sized paper filter vs. a K&N.


And on my race car, I run NO filter, like 99% of all drag cars do. And I'd hazard a guess that drag cars make up the majority of "little guy" racing. I don't know of any that use a filter, much less a K&N.

Dirt track cars need a filter, and I've got to tell you, I've talked to a lot of engine builders both in person and online, that say they can tell in tear-down which type of filter has been run on an engine.

 

[Gillbot]

Um, you asked:

And I gave you some evidence of exactly what you asked for. Then you change the criteria?

"real world results" cannot be measured, in the very minute amounts we're talking here.

How can a dyno test not equal 'real world results'? That's a 'real world' as it gets....a test on an actual vehicle, not a flowbench.

Unless you gain a LOT of power, you can't feel it. And by a "lot", I'm talking 20hp or more. You cannot feel 5hp, and on anyone other than K&N's own tests, a simple drop-in filter does not, and cannot make that much difference.

Any 1-2-3-5hp gain you 'think' you can feel in the 'real world', is imaginary.

Oh, just so we're on the same page, I'm talking about a drop-in K&N with everything else stock. No CAI. Although I still say that even on a CAI, which CAN make some more power, you won't see anymore power with a correctly-sized paper filter vs. a K&N.


And on my race car, I run NO filter, like 99% of all drag cars do. And I'd hazard a guess that drag cars make up the majority of "little guy" racing. I don't know of any that use a filter, much less a K&N.

Dirt track cars need a filter, and I've got to tell you, I've talked to a lot of engine builders both in person and online, that say they can tell in tear-down which type of filter has been run on an engine.

I'm not talking about a CAI either, and we're splitting hairs here because many people can't feel 20HP either, but an engine dyno with back to back runs in front of my own eyes on MULTIPLE motors suggests otherwise. When you are in competitive racing, a "1-2-3-5hp gain" is still a gain and worth it.

 

[Pacfanweb]

I'm not talking about a CAI either, and we're splitting hairs here because many people can't feel 20HP either, but an engine dyno with back to back runs in front of my own eyes on MULTIPLE motors suggests otherwise. When you are in competitive racing, a "1-2-3-5hp gain" is still a gain and worth it.

I agree, any gain on a race motor is worth it.

But the original subject isn't about race motors, it's about stock vehicles, and my original assertation about a drop-in K&N (no CAI) not making any difference still stands.

We're getting way off on a tangent about CAI's and race engines.

 

[Farfrumhumpn]

If its a race motor K/N is supposedly very good but forget about a recharge kit or cleaning it. Once it's soiled its never going to be better than a Fram or any other filter. Use it for a couple of races then replace it. I had some friends down south that ran thier MOPAR dragsters with K/N filters but they replaced them each race day. Other than that I don't know anyone that has ever used one off-track.

 

[Gillbot]

I agree, any gain on a race motor is worth it.

But the original subject isn't about race motors, it's about stock vehicles, and my original assertation about a drop-in K&N (no CAI) not making any difference still stands.

We're getting way off on a tangent about CAI's and race engines.

I'm not specifically speaking of race motors entirely. I've seen gains on street motors also. Dyno proven, though you could clearly see the lean condition the K&N was causing due to lack of filtration.

Could it be an aged paper filter? Perhaps.