Hey guys, first let me say that I'm sure someone is going to scorn me for posting another K&N thread but I have looked through a lot of old ones and I am confused by the people arguing for and against K&N. It seems like both sides have their points. I was considering getting a K&N for my car for fuel mileage reasons. So I was wondering how many people here see an increase in their gas mileage with a K&N compared to a paper filter? Also has anyone have solid proof that their engine is dying from using a K&N? And how about the opposite? If it affects any of your answers my car is an 04 Civic. On the sidenote, I switched out my moms K&N on her 04 Camry a few weeks ago and put in an OEM filter that only had 5k miles on it. She didn't know that I switched it but a few days later she told me that her car was feeling slower than usual. Thanks in advance for any replies.
Confused about K&N
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When I bought my 2000 Mountaineer 5.0 V8 used in July of 2004, it was completely stock and got 12 mpg. I added a K&N air filter and MPG went up to 12.5 mpg. Not much of a difference but every little bit helps. I then decided to get a MAC intake kit (tube and cotton-gauze filter) and my gas mileage shot up to almost 14 mpg. I'm waiting to rack up the miles so I can do a UOA and see if the 0W-20 is holding up and if the intake kit is causing increased wear.
I'm surprised that there are hardly any companies advertising that their intake kits give you better mileage. With the price of gas nowadays, I'm sure even average motorists would fork out the cash to get better mileage.
I'm surprised that there are hardly any companies advertising that their intake kits give you better mileage. With the price of gas nowadays, I'm sure even average motorists would fork out the cash to get better mileage.
My Sentra with 175,000 miles is not getting better gas mileage using K & N. But, it does run better. It idles better. At wide open throttle, it runs like a bat out of .... But, that does not help the fuel economy.
So, fuel economy is less, but I have less of a problem getting out of the way of traffic if I need to.
I would stay with the OEM filter. The proof that you say you might need is something you need to "prove" to yourself. Do a UOA for each of 10k OCI's. K/N, OEM filter and NO filter. (Silicon) is a HUGE tell.Compare and contrast the three.
There are only a few factors at work here. And this is where the air intake/oiled media air filter marketeers do their finest work.
Most if not all air intake and (filter systems being a part) are specified to pass a "snow prophalactic" test. The practical sentence would be; i.e, after hitting a snow drift of 3 feet.... yada yada. Otherwise one runs the risk of snow/water ingestion and a % of hydrolocked engines is not a good gig. So the air intake system is designed to be somewhat of a maze to snow, and somewhat less to its sister condition- water. This maze can be seen in some if not most cases as "restrictive" SO... simple removal will make it LESS RESTRICTIVE!!??
So if one determines the snow prophalactic is unneeded with the attending exposures to snow and water and greater exposure to chance of warranty denial IF you happen to hydrolock the engine then....
If you do a dyno before and after removal, you will find viola- "FOUND" HP !!! Of course a certain amount of gain and or loss can be attributed to measurement error.
Another issue and the fine print on oil media air filters will warn you against; will be oiling too much. Even if you oil it just right you increase the chance of mineral oil migrating to the critical MAF components that have been known to fail after being coated with mineral oil.
So to me:
1. oil filter media does not filter as well as oem paper/synthetic
2. oil can migrate to intake and critical MAF components increasing the chance of failure due to oil migration
3. oil and oil cleaner media costs too much
4. the filter media costs WAY more than OEM filters
5. you have to clean the cotton/foam media and re apply the mineral oil. If a shop were to do this, they probably would charge you 1/2 hour of shop time say at the going rate of 95 per hour. It is of course an unspoken given that one does this themselves.
[ May 11, 2005, 10:45 AM: Message edited by: ruking77 ]
There are only a few factors at work here. And this is where the air intake/oiled media air filter marketeers do their finest work.
Most if not all air intake and (filter systems being a part) are specified to pass a "snow prophalactic" test. The practical sentence would be; i.e, after hitting a snow drift of 3 feet.... yada yada. Otherwise one runs the risk of snow/water ingestion and a % of hydrolocked engines is not a good gig. So the air intake system is designed to be somewhat of a maze to snow, and somewhat less to its sister condition- water. This maze can be seen in some if not most cases as "restrictive" SO... simple removal will make it LESS RESTRICTIVE!!??
So if one determines the snow prophalactic is unneeded with the attending exposures to snow and water and greater exposure to chance of warranty denial IF you happen to hydrolock the engine then....
If you do a dyno before and after removal, you will find viola- "FOUND" HP !!! Of course a certain amount of gain and or loss can be attributed to measurement error.
Another issue and the fine print on oil media air filters will warn you against; will be oiling too much. Even if you oil it just right you increase the chance of mineral oil migrating to the critical MAF components that have been known to fail after being coated with mineral oil.
So to me:
1. oil filter media does not filter as well as oem paper/synthetic
2. oil can migrate to intake and critical MAF components increasing the chance of failure due to oil migration
3. oil and oil cleaner media costs too much
4. the filter media costs WAY more than OEM filters
5. you have to clean the cotton/foam media and re apply the mineral oil. If a shop were to do this, they probably would charge you 1/2 hour of shop time say at the going rate of 95 per hour. It is of course an unspoken given that one does this themselves.
[ May 11, 2005, 10:45 AM: Message edited by: ruking77 ]
I've never noticed a fuel mileage jump when using K&N. According to the flow test you likely won't after a few miles. Going by the theory that a more worn engine would use more gas I'd say a paper filter will give you better results in the long run.
-T
-T
I installed a K&N FIPK for my 01 Tacoma & while I didnt see a major gain in hp, I did pick up 2 or 3 mpg.
I have always run K&N's on my vehicles & I have NEVER had a problem with them.
I have always run K&N's on my vehicles & I have NEVER had a problem with them.
I have a '91 Dodge/Cummins, W-250, 4X4. The stock Mopar filters were around $48.00 ea., so I opted for the K&N, which, was $52.00, at the time. I bought it because it wasn't much more expensive and was reusable.
Regarding performance, I have a 30 lb. boost guage on my truck and I could "bury the needle" if I put my foot into it.
I have since gone back to paper element filters because the K&N let in a lot of dust. I live in Phoenix, AZ. which is a dusty, desert environment. With the paper filter, the boost guage will only go to 25 lbs., now, which makes me think that the K&N does let more air in.
BTW, when I noticed all the dust in the plenum between the filter and the turbo, I called K&N and they refunded the purcase price of the filter and paid the shipping of the filter back to them. They even asked about any damage to the engine that could be attributed to the use of the K&N. I couldn't honestly say that the engine was damaged but, I'm sure all that dirt didn't do it any good. However, I must commend them for offering some compensation.
On my new '03 Dodge/Cummins, I installed an AFE Pro-Guard 7 filter system. It's somewhat like the K&N but, has 5 plys of cotton gauze and 2 plys of a randomly woven synthetic media. It's supposed to filter almost as well as a paper element filter but, has the ability to move more air than the paper filter. However, I have not noticed more boost with the AFE-PG-7 than with the stock filter. I have not noticed any dust getting into the air intake plenum with this new system.
Hope this helps.
Joe Fihn
Regarding performance, I have a 30 lb. boost guage on my truck and I could "bury the needle" if I put my foot into it.
I have since gone back to paper element filters because the K&N let in a lot of dust. I live in Phoenix, AZ. which is a dusty, desert environment. With the paper filter, the boost guage will only go to 25 lbs., now, which makes me think that the K&N does let more air in.
BTW, when I noticed all the dust in the plenum between the filter and the turbo, I called K&N and they refunded the purcase price of the filter and paid the shipping of the filter back to them. They even asked about any damage to the engine that could be attributed to the use of the K&N. I couldn't honestly say that the engine was damaged but, I'm sure all that dirt didn't do it any good. However, I must commend them for offering some compensation.
On my new '03 Dodge/Cummins, I installed an AFE Pro-Guard 7 filter system. It's somewhat like the K&N but, has 5 plys of cotton gauze and 2 plys of a randomly woven synthetic media. It's supposed to filter almost as well as a paper element filter but, has the ability to move more air than the paper filter. However, I have not noticed more boost with the AFE-PG-7 than with the stock filter. I have not noticed any dust getting into the air intake plenum with this new system.
Hope this helps.
Joe Fihn
I have used K&N's on four trucks since 1997 and in each case I have noticed grit on the intake ducting on the supposed "clean" side of the K&N, and I have also noticed an increase of power with these K&N's.
On one truck, a 95 Exploder, I have observed a 1.5 mpg increase, when the intake was coupled with a Dynomax cat-back exhaust... this truck has a trip computer, which makes tracking mileage changes easy.
I have decided not to use a K&N anymore on my F250 4x4, because it is used off-road and I don't feel the performance trade-off versus the crappier filtering is worth it.
On the other trucks, which are used exclusively on the street, I decided that the grit factor wasn't too severe, so I have kept the K&N's, but I change oil & oil filter more often to compensate.
On one truck, a 95 Exploder, I have observed a 1.5 mpg increase, when the intake was coupled with a Dynomax cat-back exhaust... this truck has a trip computer, which makes tracking mileage changes easy.
I have decided not to use a K&N anymore on my F250 4x4, because it is used off-road and I don't feel the performance trade-off versus the crappier filtering is worth it.
On the other trucks, which are used exclusively on the street, I decided that the grit factor wasn't too severe, so I have kept the K&N's, but I change oil & oil filter more often to compensate.
I tried a K&N filter on my Volvo, noticed no difference in operation, but did get some light dusting on the "clean" side of the air filter housing. Back to the OEM Mann filters for me.
If the complete air intake system does improve mileage, will it improve mileage enough to more than pay for itself?
Ken
If the complete air intake system does improve mileage, will it improve mileage enough to more than pay for itself?
Ken
I'll "ditto" the above. I had a '89 pontiac boneville with the 3800 V6. It wasn't the tuned port model but the earlier 3800. It had such a tiny air filter and I really could feel a difference when running the K&N but, like the others, I had grit in the intake between the filter and the throttle body.
OK here's what I don't understand...
How is it possible for one air filter to improve gas mileage over another, if gas mileage is measured at very light throttle angles where both filters would be of sufficient flow?
Let's say your engine at WOT assuming 80% VE can ingest 500 CFM of air. Your stock airbox and paper filter flows 600, and a K&N drop-in filter flows 840. First question is, is the airbox going to let the K&N breathe to it's utmost potential? Probably not. Second question is, If the stock setup flows more (albiet marginally) than the engine could ever use, what gain is there in installing a filter that can flow even more?
Back to the MPG thing...Experts correct me on this, but if you're crusing down the road at 60MPH in the aforementioned example vehicle, chances are you're not flowing more than 150 CFM past the throttle plates, so therefore any filter, even one of half the CFM of the OEM one would perform equally and deliver the same MPG.
Am I right or not? If not, explain.
How is it possible for one air filter to improve gas mileage over another, if gas mileage is measured at very light throttle angles where both filters would be of sufficient flow?
Let's say your engine at WOT assuming 80% VE can ingest 500 CFM of air. Your stock airbox and paper filter flows 600, and a K&N drop-in filter flows 840. First question is, is the airbox going to let the K&N breathe to it's utmost potential? Probably not. Second question is, If the stock setup flows more (albiet marginally) than the engine could ever use, what gain is there in installing a filter that can flow even more?
Back to the MPG thing...Experts correct me on this, but if you're crusing down the road at 60MPH in the aforementioned example vehicle, chances are you're not flowing more than 150 CFM past the throttle plates, so therefore any filter, even one of half the CFM of the OEM one would perform equally and deliver the same MPG.
Am I right or not? If not, explain.
If you have a decent closed loop fuel injection sytem it should be doing a decent job if adjusting fuel mixture, preventing any significant loss in mileage with a mildly restricted filter.
If you have an open loop fuel injection system or a carbrueted engine, then the mixture gets richer as the filter gets more restricted and your fuel consumption increases.
Or, if you really really really believe that filter restriction causes a drop in milage you might even see it with a properly functioning modern closed loop fuel injections system.
OK, here's my understanding (I'm obviously NOT an engineer):
A filter with lower restriction requires less pressure differential (vacuum) to achieve a given air flow through the filter.
If an engine requires x cfm airflow to maintain a certain vehicle speed, even if a paper or K&N filter flows >x cfm, the filter that has the lower restriction to air flow will flow a greater volume of air through it at a given engine vacuum. I guess this is why, in theory, the engine's volumetric efficiency increases with the use of a low restriction air filter.
I've seen bike motors die an early death in the desert running them. We called the telltale scratching of the intake valve faces "K&N" marks.
They're fine in the right applications, but if engine longevity is what your after I'd pass. IMO they will negate all the benfits of your super duper oil selection. Some will say their oil anylisis hasn't showed anymore sil? But what about the sil that came through the intake, took trip up and down the bore then out the exhaust without getting in the oil?
They're fine in the right applications, but if engine longevity is what your after I'd pass. IMO they will negate all the benfits of your super duper oil selection. Some will say their oil anylisis hasn't showed anymore sil? But what about the sil that came through the intake, took trip up and down the bore then out the exhaust without getting in the oil?
As far as actual experience we did run back to back tests on a 1998 Ford Contour V6 at the dealership. The only difference was a drop in K&N on the two 12 mile loops we drove. This was done on an employees car. We used the standard Hickok NGS to record the mileage as reported by the PCM. Long story short, no difference was noted. The car's owner was dissapointed but his intake was slightly louder so he got his $50 worth.
I still have not found anyone who can DOCUMENT an actual mileage gain with a drop in, or a HP gain (independant dyno tests not affiliated /paid by/sponsored by K&N). I know the profile- "I just paid $50 for a K&N, it has to be good or else I wouldn't have paid the money for it".
Not going to argue the benefits of a CAI, as some of those do work as advertised.
I still have not found anyone who can DOCUMENT an actual mileage gain with a drop in, or a HP gain (independant dyno tests not affiliated /paid by/sponsored by K&N). I know the profile- "I just paid $50 for a K&N, it has to be good or else I wouldn't have paid the money for it".
Not going to argue the benefits of a CAI, as some of those do work as advertised.
I think that in my experience (though, no dyno proof) most of the cars that see gains are cars that have sub-optimal filtration to begin with. This is exacerbated by a forced induction intake system, like an my turbo ford. Swapping from the screwy stock intake to a k&n cone filter is CONSIDERABLY more than a "minor" improvement. It's not a "wishful thinking" thing either. My turbo started spooling about 500rpm sooner after I put on the K&n. Do I have proof? No. Do I think the k&n is doing damage to my motor? Could be, the UOA will tell the tell.
-asi
This makes sense at WOT, where any restriction in the intake is going to decrease VE, but what about the enourmous restriction that's already there while cruising known as the throttle plate? It's basically decreasing VE as it closes, so I still don't see your point as being valid, unless I'm missing something quite obvious (which has been known to happen).
Can you shed more light on your theory?
On our Exploder, we experienced the fuel economy gain when we changed the filter AND the cat-back exhaust. There was a noticeable increase in power.
My wife drives the Exploder, and her driving habits were unchanged before and after the modifications.
My theory is that since the engine produces more power now, she doesn't need to "give it as much gas" to accelerate at the same rate she's used to, and she does not need to "give it as much gas" to maintain her normal cruising speeds... hence, the increase in fuel economy.
Again, since we did the air filter and the exhaust at the same time, I cannot attribute the gain exclusively to one mod or the other.
My wife drives the Exploder, and her driving habits were unchanged before and after the modifications.
My theory is that since the engine produces more power now, she doesn't need to "give it as much gas" to accelerate at the same rate she's used to, and she does not need to "give it as much gas" to maintain her normal cruising speeds... hence, the increase in fuel economy.
Again, since we did the air filter and the exhaust at the same time, I cannot attribute the gain exclusively to one mod or the other.
>Ok, my curiosity is piqued, John. I thought
that K&N's were supposed
>to be the trick thing to use for air filtering? Also, do you have any
>good ideas about routing a duct to the windshield cowling? Would it
>make that big a difference in terms of hp? (or any at all?)
K&N is simply the company that spends the most ad dollars and therefore
gets the most attention. I learned my very expensive K&N lession
over 20 years ago when I was actively building racing engines. K&N
had some contingency money available so I replaced our Filtron
(Oiled foam) filters on our motocross bikes with K&N. An engine that
would normally last 10-15 heats was completely trashed by dirt
before the first one was over. Frankly I've never seen such massive
filter failure. Figuring it was a fluke, I tried it again at
another race. Same result. Massive wear, grit all over the
intake track - trashed engine. Lesson learned. The K&N that
came on a used Z I bought awhile back is exactly the same
construction as the 20 year old filter still somewhere in my junk
collection.
K&N follows a familiar path. Lots of hype, lots of advertising
dollars which effectively buys them good press, and an excellent
no-questions-asked warranty. A warranty that pays people off
to keep 'em quiet. One can get away with a lot on the street
simply because there isn't much dirt under normal conditions.
But off-road is another matter. There is an easy test of a
filter that you can do. Simply thoroughly clean the air cleaner
housing and the carb intake. Then coat it with a very thin coating
of light grease. A portion of any dirt that gets through the filter
will be trapped in the grease. Run it awhile and then feel the grease.
If it is gritty, the filter isn't working. It will be gritty with
a K&N.
There is simply no better filtration media than paper. The very best
filters, HEPA filters, used to catch sub-micron particles in nuclear
plants and hard disk drives, is simply a very refined paper. If the
paper element doesn't flow enough air, install a larger one. The only
time I won't use a paper element is when there is a possibility that
the filter element can become wet. Then I'll use oiled foam. For
REALLY dusty environments such as dirt tracks and off-road racing,
I'll do like every other mechanic and use a foam prefilter over
a paper element.
As far as picking up air under the cowl, you can simply go through the
firewall above the partition that separates the cowl space from
the interior. I've done that with stock carb setups. Depending on how
far the horns of the webers stick out, this may or may not be easy.
that K&N's were supposed
>to be the trick thing to use for air filtering? Also, do you have any
>good ideas about routing a duct to the windshield cowling? Would it
>make that big a difference in terms of hp? (or any at all?)
K&N is simply the company that spends the most ad dollars and therefore
gets the most attention. I learned my very expensive K&N lession
over 20 years ago when I was actively building racing engines. K&N
had some contingency money available so I replaced our Filtron
(Oiled foam) filters on our motocross bikes with K&N. An engine that
would normally last 10-15 heats was completely trashed by dirt
before the first one was over. Frankly I've never seen such massive
filter failure. Figuring it was a fluke, I tried it again at
another race. Same result. Massive wear, grit all over the
intake track - trashed engine. Lesson learned. The K&N that
came on a used Z I bought awhile back is exactly the same
construction as the 20 year old filter still somewhere in my junk
collection.
K&N follows a familiar path. Lots of hype, lots of advertising
dollars which effectively buys them good press, and an excellent
no-questions-asked warranty. A warranty that pays people off
to keep 'em quiet. One can get away with a lot on the street
simply because there isn't much dirt under normal conditions.
But off-road is another matter. There is an easy test of a
filter that you can do. Simply thoroughly clean the air cleaner
housing and the carb intake. Then coat it with a very thin coating
of light grease. A portion of any dirt that gets through the filter
will be trapped in the grease. Run it awhile and then feel the grease.
If it is gritty, the filter isn't working. It will be gritty with
a K&N.
There is simply no better filtration media than paper. The very best
filters, HEPA filters, used to catch sub-micron particles in nuclear
plants and hard disk drives, is simply a very refined paper. If the
paper element doesn't flow enough air, install a larger one. The only
time I won't use a paper element is when there is a possibility that
the filter element can become wet. Then I'll use oiled foam. For
REALLY dusty environments such as dirt tracks and off-road racing,
I'll do like every other mechanic and use a foam prefilter over
a paper element.
As far as picking up air under the cowl, you can simply go through the
firewall above the partition that separates the cowl space from
the interior. I've done that with stock carb setups. Depending on how
far the horns of the webers stick out, this may or may not be easy.
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