Very interesting air filter test. Att'n: K&N owners...
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Sorry, but the link to this "test" has been posted here several times before.
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=15;t=000308;p=1
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=15;t=000265#000000
I am a long time K&N user and this test did nothing to change my mind about using them. 99% of the problems that you will hear about the K&Ns come from poor maintenence, not bad filter design.
http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=15;t=000308;p=1
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=15;t=000265#000000
I am a long time K&N user and this test did nothing to change my mind about using them. 99% of the problems that you will hear about the K&Ns come from poor maintenence, not bad filter design.
I drive about 60,000 miles per year. Mileage is important to me. I fill my vehicle about 4 times a week and calculate gas mileage at each fill up. I write the odometer reading and gas mileage on each receipt, been doing this for years.
I bought a '97 Tahoe with 33,000 miles on it. I ran paper filters on it until about 80,000 miles. My average gas mileage was 17.0 MPG. I noticed an immediate improvement when I installed the K&N filter. My average gas mileage went to 18.5 MPG. The vehicle now has 341,000 miles on it. I live in West Texas and it is very dry and dusty here. I believe that if the K&N was passing a lot of dirt, I'd be having problems by now. I clean & oil the filter every 50,000 miles. I also change the engine oil & filter every 5,000 miles.
I was so impressed with the improvement from the K&N filters that I bought them for my three other vehicles. Unfortunately, I saw NO IMPROVEMENT in mileage or performance whatsoever.
As an engineer, I was very surprised to see any improvement in the Tahoe because I expected the closed-loop air/fuel ratio control to keep things the same. I still don't understand what is happening, but I know that there is a definite, DOCUMENTED mileage increase of 8%. I still have all the receipts. Nothing else was changed on the vehicle, and I drove the same routes at the same speeds.
Based on the increase of 1.5 average MPG, I've saved more than 1200 gallons of fuel over the 260,000 miles I've driven with this filter. At the average gasoline price for that time period, the filter probably saved me about $1500.
I have no affiliation with K&N. I wish I knew why this one vehicle improved so much but the others didn't. Moreover, I wish the other vehicles experienced the same improvement!
I bought a '97 Tahoe with 33,000 miles on it. I ran paper filters on it until about 80,000 miles. My average gas mileage was 17.0 MPG. I noticed an immediate improvement when I installed the K&N filter. My average gas mileage went to 18.5 MPG. The vehicle now has 341,000 miles on it. I live in West Texas and it is very dry and dusty here. I believe that if the K&N was passing a lot of dirt, I'd be having problems by now. I clean & oil the filter every 50,000 miles. I also change the engine oil & filter every 5,000 miles.
I was so impressed with the improvement from the K&N filters that I bought them for my three other vehicles. Unfortunately, I saw NO IMPROVEMENT in mileage or performance whatsoever.
As an engineer, I was very surprised to see any improvement in the Tahoe because I expected the closed-loop air/fuel ratio control to keep things the same. I still don't understand what is happening, but I know that there is a definite, DOCUMENTED mileage increase of 8%. I still have all the receipts. Nothing else was changed on the vehicle, and I drove the same routes at the same speeds.
Based on the increase of 1.5 average MPG, I've saved more than 1200 gallons of fuel over the 260,000 miles I've driven with this filter. At the average gasoline price for that time period, the filter probably saved me about $1500.
I have no affiliation with K&N. I wish I knew why this one vehicle improved so much but the others didn't. Moreover, I wish the other vehicles experienced the same improvement!
well, I would venture to say that in the case of your Tahoe the stock or previous setup was starving the engine for air. The ECU/MAF etc can only compensate so much...
A friend has a Tahoe (not sure what year but it's close) and he claims that the stock setup is woefuly inadequate. He uses a cone inside the existing airfilter box and claims similar improvements over many years of use. in a nutshell all he did was basically increase the filter surface area. Which is has the same net result as what you did by switching to a less-restrictive filter of the same area.
My theory:
most likely any filter that improves airflow would have helped. The reason your other cars didn't see an improvement is that there was nothing wrong with the existing filter setup/design.
well, anyway, that's my opinion on the matter. (and I'm an engineer, too, so I like repeatable results. When I can't get them, it's time to look elsewhere for the real answer!)
A friend has a Tahoe (not sure what year but it's close) and he claims that the stock setup is woefuly inadequate. He uses a cone inside the existing airfilter box and claims similar improvements over many years of use. in a nutshell all he did was basically increase the filter surface area. Which is has the same net result as what you did by switching to a less-restrictive filter of the same area.
My theory:
most likely any filter that improves airflow would have helped. The reason your other cars didn't see an improvement is that there was nothing wrong with the existing filter setup/design.
well, anyway, that's my opinion on the matter. (and I'm an engineer, too, so I like repeatable results. When I can't get them, it's time to look elsewhere for the real answer!)
When I changed installed a K&N FIPK intake on my x girlfriend's Ford Explorer, I witnessed an increase in gas mileage first hand. It rose from 14.5 mpg to 17 mpg when paired with synthetic oil. Incredible for an older SUV.
I have recently removed my K&N FIPK which as been in use for 54k miles in an attempt to see if MPG and/or performance are reduced. In the 25-30 miles I've driven so far, I cannot verify via my butt-dyno any perceptable loss of power. When I removed the intake tube I noticed a thin film of dirt all along the inside wall. How large does a dirt particle have to be for it cause engine damage?
K&N salesmen have told me that their filters do not have to filter better than other competing brands, so long as they meet minimum O.E. requirements. Who knows what that is? Of course they tout that their filters have the highest dirt retention of any aftermarke filter, and that most aftermarket filters do not meet these O.E. filtration requirements. K&N filters were desigend for the racing community and soon realized that there was a huge profit potential in street applications.
On the K&N website their own dyno tests show a mere 4 hp increase over stock output in my application. Worse still is that the gain is in an RPM range that I seldom if ever use. Some vehicles will experience a bigger improvement in airflow gains simply because some intakes are very restrictive from the factory, other are pretty good and hard to improve upon. I have submitted UOA's that show no detrimental effect from the K&N, but I don't think it's worth the price they charge either.
K&N makes a quality product but like so many other things, it isn't as good as they say it is.
K&N salesmen have told me that their filters do not have to filter better than other competing brands, so long as they meet minimum O.E. requirements. Who knows what that is? Of course they tout that their filters have the highest dirt retention of any aftermarke filter, and that most aftermarket filters do not meet these O.E. filtration requirements. K&N filters were desigend for the racing community and soon realized that there was a huge profit potential in street applications.
On the K&N website their own dyno tests show a mere 4 hp increase over stock output in my application. Worse still is that the gain is in an RPM range that I seldom if ever use. Some vehicles will experience a bigger improvement in airflow gains simply because some intakes are very restrictive from the factory, other are pretty good and hard to improve upon. I have submitted UOA's that show no detrimental effect from the K&N, but I don't think it's worth the price they charge either.
K&N makes a quality product but like so many other things, it isn't as good as they say it is.
I would like to see this test performed on the Amsoil/Donaldson nano-fiber filters.
eklock,
from my personal experience I have started to believe that its the intake plumbing (resonator, housing, tube) that is the bottleneck in a "stock" car and not the filter. So using a high flow filter only makes sense if you upgrade/remove the other bottlenecks.
from my personal experience I have started to believe that its the intake plumbing (resonator, housing, tube) that is the bottleneck in a "stock" car and not the filter. So using a high flow filter only makes sense if you upgrade/remove the other bottlenecks.
The K&N Gen II FIPK for the Grand Cherokee V8 showed a gain of 26.3 RWHP on a '98 5.9 Limited. Now how they got a full-time 4WD vehicle on a rear-wheel dyno is beyond me (pull the front shaft???) or just how much of these numbers are fabricated.
I had a '93 Grand Cherokee with the 5.2, and noticed little to no difference over the stock airbox. Though I do see the one thing that really gets my attention in the FIPK...The tiny little air hat on the throttle body is significantly larger. Large enough to rub on the hood if the engine is torqued enough! By looking at the size of the factory air hat, it's tough to determine if this is a restriction or not.
I now have a '98 Grand Cherokee 5.2, and it's all stock for now, but I'm still mulling the whole FIPK idea around in my head. Even a 10 HP gain would be worth getting it, IMHO, but whether there is 10 HP to be gained from it is the biggest reason I haven't taken this further. I need to see real world numbers and/or unbiased testimonials from owners that have it.
If I did decide to get this setup, would there be anything to gain as far as added filtration from one of those nylon mesh prefilters that are available to add over the cone, or would this defeat any possible gains from adding a higher flowing intake system? Do they really work to reduce the amount of micro-fine dirt passing thru the K&N element?
Sorry if this was a bit of random babble...I'm tired.
I had a '93 Grand Cherokee with the 5.2, and noticed little to no difference over the stock airbox. Though I do see the one thing that really gets my attention in the FIPK...The tiny little air hat on the throttle body is significantly larger. Large enough to rub on the hood if the engine is torqued enough! By looking at the size of the factory air hat, it's tough to determine if this is a restriction or not.
I now have a '98 Grand Cherokee 5.2, and it's all stock for now, but I'm still mulling the whole FIPK idea around in my head. Even a 10 HP gain would be worth getting it, IMHO, but whether there is 10 HP to be gained from it is the biggest reason I haven't taken this further. I need to see real world numbers and/or unbiased testimonials from owners that have it.
If I did decide to get this setup, would there be anything to gain as far as added filtration from one of those nylon mesh prefilters that are available to add over the cone, or would this defeat any possible gains from adding a higher flowing intake system? Do they really work to reduce the amount of micro-fine dirt passing thru the K&N element?
Sorry if this was a bit of random babble...I'm tired.
The prefilters help cut down on dirt, but if they filtered smaller particles than the filter itself, it would seem to me they would be very restrictive. Which they are not. So maybe they are best at extending cleaning intervals of the filter they cover.
Anyway, most of the gain on aftermarket intakes is the intake, and not the filter they throw on them. So there's nothing stopping you from putting a better filter on an aftermarket intake. Paper cone filters are a good choice, or if you wanted to stick to a performance filter, AEM dryflow supposedly filter better. Certainly looks more solid.
Anyway, most of the gain on aftermarket intakes is the intake, and not the filter they throw on them. So there's nothing stopping you from putting a better filter on an aftermarket intake. Paper cone filters are a good choice, or if you wanted to stick to a performance filter, AEM dryflow supposedly filter better. Certainly looks more solid.
.
Pre-filters are great for preventing water from getting on the filter.
Wet filter = no (or reduced) airflow
Wet filter = no (or reduced) airflow
Some FWIW.
AccordMDX is right.
Seldom in my experience does a filter alone on a stock engine do more than create a microscopic blip on a dyno graph... and then only at the far upper reaches of the rpm range. Usually it's not detectable. Even a compete intake/filter system may have only marginally beneficial effects on a stock engine (in the 5hp range or less- kinda within the margin for error on a chassis dyno) ... unless the stock intake is very poorly designed. A stock engine can only inhale so much. If the stock system supplies the stock engine's airflow needs, then nothing is gained. I've run at least 50 dyno tests on such things over the past 20 years and only rarely do I see an increase on a stock motor. When you do it's usually obvious why.
A free flow intake becomes more necessary when you increase the engine's ability to breathe by other means. Such mods can outstrip the stock intake system's ability to flow, so you then need to upgrade to keep pace.
As to filters, I don't use oiled cotton gauze (OCG) from anyone on my dirt rigs any longer... especially my a turbo diesels. Put a smear of grease in your intake tube somewhere past the filter. Check it in 10,000 miles or so. That will tell the tale for good or for bad when you find grit embedded. I did on three of my rigs with OCGs - and, yes, I first made sure there were no fitment problems or unfiltered air leaking by. These were all rigs used in very dirty trail environments (Land Rover, Bummer, F-250).
I'm more sanguine about using OCG filters on a street-only rig (unless used in a dusty area), but overall I'd rather have a filter that can take out 99-plus percent of the dirt than one that can barely do 96 percent. OCG with a foam precleaner is a good compromise that doesn't impact airflow much.
I like the OCG's ability to be cleaned but both my farm tractor filters are some sort of a synthetic, paper-like material that you can wash in soap and water. They gave me an idea.
I just put a filter from a big Massy Ferguson tractor on my trail rig (which has a GM 6.2L), replacing the OCG unit. It looked plenty big because it came from some 500ci monster TD, but I checked the airflow restriction with a vacuum gauge. No detectable restriction up to when the governor kicks in at 4,000rpms. This filter is 10 inches in diameter and about 18 inches long and has some sort of a cyclonic device built tin to spin out the heaviest of the dust. It has a 4.5 inch air inlet and a 3.5 inch outlet. It was hard to find space for it, so it wouldn't be for the average Honda!
AccordMDX is right.
Seldom in my experience does a filter alone on a stock engine do more than create a microscopic blip on a dyno graph... and then only at the far upper reaches of the rpm range. Usually it's not detectable. Even a compete intake/filter system may have only marginally beneficial effects on a stock engine (in the 5hp range or less- kinda within the margin for error on a chassis dyno) ... unless the stock intake is very poorly designed. A stock engine can only inhale so much. If the stock system supplies the stock engine's airflow needs, then nothing is gained. I've run at least 50 dyno tests on such things over the past 20 years and only rarely do I see an increase on a stock motor. When you do it's usually obvious why.
A free flow intake becomes more necessary when you increase the engine's ability to breathe by other means. Such mods can outstrip the stock intake system's ability to flow, so you then need to upgrade to keep pace.
As to filters, I don't use oiled cotton gauze (OCG) from anyone on my dirt rigs any longer... especially my a turbo diesels. Put a smear of grease in your intake tube somewhere past the filter. Check it in 10,000 miles or so. That will tell the tale for good or for bad when you find grit embedded. I did on three of my rigs with OCGs - and, yes, I first made sure there were no fitment problems or unfiltered air leaking by. These were all rigs used in very dirty trail environments (Land Rover, Bummer, F-250).
I'm more sanguine about using OCG filters on a street-only rig (unless used in a dusty area), but overall I'd rather have a filter that can take out 99-plus percent of the dirt than one that can barely do 96 percent. OCG with a foam precleaner is a good compromise that doesn't impact airflow much.
I like the OCG's ability to be cleaned but both my farm tractor filters are some sort of a synthetic, paper-like material that you can wash in soap and water. They gave me an idea.
I just put a filter from a big Massy Ferguson tractor on my trail rig (which has a GM 6.2L), replacing the OCG unit. It looked plenty big because it came from some 500ci monster TD, but I checked the airflow restriction with a vacuum gauge. No detectable restriction up to when the governor kicks in at 4,000rpms. This filter is 10 inches in diameter and about 18 inches long and has some sort of a cyclonic device built tin to spin out the heaviest of the dust. It has a 4.5 inch air inlet and a 3.5 inch outlet. It was hard to find space for it, so it wouldn't be for the average Honda!
getting OT here
Jim, what sort of Landy are you driving ??
Have a Defender 130 Crew Cab here. (with a Donaldson element including the plastic spinner pre-cleaner in the stock housing. The K&N was ditched after 20,000km)
I'm always copping a bagging from all the Land Cruiser, Hilux and Nissan Patrol owners in this part of the world.
Jim, what sort of Landy are you driving ??
Have a Defender 130 Crew Cab here. (with a Donaldson element including the plastic spinner pre-cleaner in the stock housing. The K&N was ditched after 20,000km)
I'm always copping a bagging from all the Land Cruiser, Hilux and Nissan Patrol owners in this part of the world.
I'm not for or against K&N filters. Saw a post about how using K&N filters will show dirt just inside the intakes of these vehicles. About half of my co workers use them on their pick up trucks. They all took their K&N filters off along with tubes leading to intakes. All of the trucks had dirt deposits inside the intakes. I know that they all maintain the filters as instructed. The guys pull them off at work to clean and re oil them. Boss got wind of the post and pulled the one on his son's pickup and he told me he saw the dirt on the intake also. Boss went back to AC DELCO air filters.
All the guys said they did see a small increase in gas mileage with the K&N's. Just seems like too much maintenance on an air filter for me.
All the guys said they did see a small increase in gas mileage with the K&N's. Just seems like too much maintenance on an air filter for me.
Saw the same thing on dirt bikes (vs. the oem oiled foam). Wear in the valve area was quite noticable as being polished away by sandblasting. These were run in the silt and sand of the desert though. Autos live a fairly clean life, often the intake tract make some hard turns or have some molding lines that catch a lot of the stuff before it hits the filter. Also the velocity of the dirt may be low enough that the media can catch it.
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