Are K&N drop ins still bad at filtering?

[nleksan]

AFE ProDryS are in my experience the best, and I use them, both panel and cone, in every car I have from street to race/track. The fitment is absolutely perfect for every one I've used, and even with TRUE cold air intakes (filter in bumper a la the Dinan carbon fiber long tube CAI, but also "ducted" air boxes such as the Bimmerworld E36 race intake and the E46 M3 CSL Carbon Fiber Intake/Manifold) the post-filter tubing stays free from buildup of any kind.

I really do recommend this option over any oiled, including AFE's (I don't have any stake in this, just offering opinion based on experience that runs the gamut of motor airflow needs and "severe usage")

 

[Shannow]

Originally Posted By: Hessam
they are not worthless... if you don't drive on dirt roads, and keep most of your driving to paved street/highways, they will filter fine. Their filtering efficiency actually improves with time.
I got one in my LX450 since about 119K miles, and my engine is doing fine. no problems whatsover, and i have never even replaced or cleaned it... it's getting about time I do something about, and thinking about going back the OEM paper filter, but I am not sure I am ready to give up my 16 mpg that I get with my K&N


How does the K and N improve your fuel economy ?

I'm assuming that you are driving at normal highway speeds, and the the throttle plate is mostly closed for nearly all of that, so then how can the K and N possible give better economy, when it's the overall restriction between air intake and inlet valve that controls your airflow/load ?

Doesn't add up.

 

[04SE]

Originally Posted By: Shannow
Originally Posted By: Hessam
they are not worthless... if you don't drive on dirt roads, and keep most of your driving to paved street/highways, they will filter fine. Their filtering efficiency actually improves with time.
I got one in my LX450 since about 119K miles, and my engine is doing fine. no problems whatsover, and i have never even replaced or cleaned it... it's getting about time I do something about, and thinking about going back the OEM paper filter, but I am not sure I am ready to give up my 16 mpg that I get with my K&N


How does the K and N improve your fuel economy ?

I'm assuming that you are driving at normal highway speeds, and the the throttle plate is mostly closed for nearly all of that, so then how can the K and N possible give better economy, when it's the overall restriction between air intake and inlet valve that controls your airflow/load ?

Doesn't add up.


Because a multi-million dollar advertising campaign says so? Along with fancy graphs and 'estimated' HP/TQ increases.

 

[wemay]

Again, addressing the OP's question; K&N air filters are not 'bad' at filtering at all but you can find paper elements that filter better. If you consider 98% significantly better than 96%.

 

[Hessam]

Originally Posted By: 04SE
Originally Posted By: Shannow
Originally Posted By: Hessam
they are not worthless... if you don't drive on dirt roads, and keep most of your driving to paved street/highways, they will filter fine. Their filtering efficiency actually improves with time.
I got one in my LX450 since about 119K miles, and my engine is doing fine. no problems whatsover, and i have never even replaced or cleaned it... it's getting about time I do something about, and thinking about going back the OEM paper filter, but I am not sure I am ready to give up my 16 mpg that I get with my K&N


How does the K and N improve your fuel economy ?

I'm assuming that you are driving at normal highway speeds, and the the throttle plate is mostly closed for nearly all of that, so then how can the K and N possible give better economy, when it's the overall restriction between air intake and inlet valve that controls your airflow/load ?

Doesn't add up.


Because a multi-million dollar advertising campaign says so? Along with fancy graphs and 'estimated' HP/TQ increases.


No because I actually measure my MPG for every tank of gas. My average has been 16.2 with the K&N filter with about 75% highway and 25% city driving. with my old OEM filter my average was 15.1 and the highest tank I ever got was 15.8.

The K&N can have an increase in MPG in some engines. They engines they work on best are the old school engines, without a lot of modernized computerized management. To best of my knowledge even though the LX450 does had fuel injection, it's a very basic FI set-up and the main block is essentially an old Buick I6 from the 60's which had been used in most landcruisers until the mid 90's.

 

[OVERKILL]

Originally Posted By: Hessam
Originally Posted By: 04SE
Originally Posted By: Shannow
Originally Posted By: Hessam
they are not worthless... if you don't drive on dirt roads, and keep most of your driving to paved street/highways, they will filter fine. Their filtering efficiency actually improves with time.
I got one in my LX450 since about 119K miles, and my engine is doing fine. no problems whatsover, and i have never even replaced or cleaned it... it's getting about time I do something about, and thinking about going back the OEM paper filter, but I am not sure I am ready to give up my 16 mpg that I get with my K&N


How does the K and N improve your fuel economy ?

I'm assuming that you are driving at normal highway speeds, and the the throttle plate is mostly closed for nearly all of that, so then how can the K and N possible give better economy, when it's the overall restriction between air intake and inlet valve that controls your airflow/load ?

Doesn't add up.


Because a multi-million dollar advertising campaign says so? Along with fancy graphs and 'estimated' HP/TQ increases.


No because I actually measure my MPG for every tank of gas. My average has been 16.2 with the K&N filter with about 75% highway and 25% city driving. with my old OEM filter my average was 15.1 and the highest tank I ever got was 15.8.

The K&N can have an increase in MPG in some engines. They engines they work on best are the old school engines, without a lot of modernized computerized management. To best of my knowledge even though the LX450 does had fuel injection, it's a very basic FI set-up and the main block is essentially an old Buick I6 from the 60's which had been used in most landcruisers until the mid 90's.


The only time a potential increase in airflow could be realized would be at WOT. Other than that, the biggest restriction is the throttle blade.

 

[Hessam]

Not disagreeing with you Overkill... but engine compression ratio and torque also play a role in that equation. Higher compression / higher torque engines could theoretically realize a bigger gain from increased air flow rate to the engine.

 

[OVERKILL]

Originally Posted By: Hessam
Not disagreeing with you Overkill... but engine compression ratio and torque also play a role in that equation. Higher compression / higher torque engines could theoretically realize a bigger gain from increased air flow rate to the engine.


But only at WOT when the throttle blade is not the biggest restriction. Perhaps there are OEM's out there that utilize an airbox that does not provide sufficient flow with a factory element to realize the engine's full potential at WOT but these would be rare exceptions as the design parameters are on the generous side to allow for filter age and loading.

Often times there is also a silencer in front of the airbox that is more restrictive than the filter assembly as well. This was the case on the old Fox body Mustangs. Removing the silencer was just as effective as a CAI. But again, the gains were only at WOT.

If one were to fit a vacuum gauge or vacuum sensor and affix it to a datalogging device with it situated in FRONT of the throttle body, between it and the filter, one could measure any realtime restriction taking place.

 

[robert_k]

I for ONE can testify that my motorcycle engine was damaged by my K & N filter ! The throttle body was dusty when I checked it & now the bike uses oil !
I can ALSO tell you that the air filter is the MOST important filter on your engine. It filters far more "product" than any other filter.
As a retired Cummins tech, I can also tell you that it takes only ONE oz of road dust per 100 cubic inches of engine, ingested , to RUIN your engine. I witnessed the tests on Cummins factory dyno & watched an 855 CI engine purposely ruined by 8 oz of dust collected form dusty air filters.
I have yet to be convinced that any air filter that flows MORE air doesnt also flow MORE dust !

 

[nleksan]

Overkill, you should be familiar enough with the BMW world to know just how significant of gains can be had on the S54 with "more airflow" via the CSL dry carbon fiber manifold (I have a first production run OE on mine, 13-44rwhp and 8-41rwtq gains from 2k to 8.8krpm!)...

I do only recommend AFE ProDryS for high flow filters, been using them forever and they're everything K&N is reputed to be, but isn't...

 

[SteveSRT8]

Extremely vehicle specific info here. Platform A may realize an increase from a CAI but platform B may not.

In my sig car they are a joke. Even with 6.1 liters producing around 450 hp in ideal conditions they cannot do much except move the torque peak higher up the curve and add a ton of noise.

Now if you have opened the engine with mods then it may be beneficial, but that is wildly specific to what you have had done.

Special note re: dyno claims. I have seen dynos vary far more than the claimed increase by the CAI mfgr. Mostly smoke and mirrors.

 

[OVERKILL]

Originally Posted By: nleksan
Overkill, you should be familiar enough with the BMW world to know just how significant of gains can be had on the S54 with "more airflow" via the CSL dry carbon fiber manifold (I have a first production run OE on mine, 13-44rwhp and 8-41rwtq gains from 2k to 8.8krpm!)...

I do only recommend AFE ProDryS for high flow filters, been using them forever and they're everything K&N is reputed to be, but isn't...


But that's WOT airflow gain, I have no issue with that, sometimes that can be an issue as I noted above with my Mustang example. However the gains are ONLY at WOT, when the engine can consume the most air.

 

[wemay]

Put them in (K&N) about two weeks ago and I sill still defend them for reasons i've stated but...

In the last two weeks i have come to the conclusion that the extra sound levels are not pleasing. Especially in the 2.4. The filter just amplifies the harshness of the engine note when at 1/2 throttle and above. Nope, not pleasing at all. As for the Turbo? My wife just does not like the louder whooooosh either, so....both have been replaced with paper filters.

 

[Lightninrod]

Just replaced the K&N oiled air filter with a dry AFE Pro dry filter.

Dan

 

[Leonardo629]

According to the ISO5011 test results K&N publishes, cotton gauze filters at worst have around 1% or less filtering efficiency than OE. I couldn't find the efficiency requirement of OE filters, but I think they have to have at least 99% efficiency base on what I've found on the internet.

AFE pro dry S filters have OE like efficiency, but then it probably flows just like an OE filter, so washability would be the sole reason you use such filters.

I'm sticking with property serviced/oiled cotton filter since I drive in the suburbs, and my UOA results show no elevated si count.

 

[Nick1994]

Have you ever held a K&N up the the light? You can see right through it. You could stick a toothpick right through each hole, not even by stretching each hole.

Rock catcher IMO

 

[wemay]

Yup, ask Porsche. They always use "rock catchers" in their most expensive, technically advanced vehicles...

http://www.bmcairfilter.com.au/porsche-918-spyder-assembly-line/

(BMC is, like K&N, an oiled cotton gauze air filter)

 

[Camprunner]

have used them several times over the past 20 years with no issues at all. Several different cars and trucks I clean and re-oil them usually between 40-60,000 miles it really depends on how it looks. I have seen some millage improvement on some of my cars and trucks I have not noticed any power gain not that I was looking for any. I have had my oil tested on several of my rides over the years also did some tests switching back and forth between the K&N and factory filter and have seen little to no change in the silicon content in my UOA so I keep running them. I like the ability to reuse them I ran one on my Dodge Durango for 255,000 miles without issue before I traded her in. Some people hate them some people love them to each his own.

 

[Torrid]

I'm kind of surprised by the results I've just seen. My Jag had a K&N installed when I bought it. I just removed it and replaced it with a paper STP filter. First thing I noticed was that throttle response did drop. Intake noise is now greatly reduced. I always thought the car sounded much different than our old S-Type, but I chalked that up to the differences in design between the 4.0 V8 and 4.2 V8. It now sounds very similar to me. I didn't think a filter would make that much difference. I can see why some swear by the K&N, but after I had an oiling issue with a previous car affecting the MAF that required constant MAF cleaning no matter how light I oiled it, I just don't bother with them.

 

[meep]

I just recently went through this. amazon had one discounted in my size due to a mangled box so I bought it and ran it for a year. It was really well made, came oiled, and fit the air box well. I drove on it for a year which included 5 long-towing trips. That means hours on end of lots of throttle, lots of air.

I took it off this summer to check it, and found a very faint, but easily visible coating of brown dust downstream from the filter in the intake tract.

As much as I wanted to like the K&N, I couldn't do that. I put a paper one back in. I do not live in a dusty location, and the intake was clean when I installed the K&N.

-m