K&N makes the assumption that the filter itself is the restriction in the intake system. If the filter is properly sized it will already meet the requirements of the engine. The engine only demands so much airflow, a filter can't shove more in.
K&N filters do they increase gas mileage?????????
- Thread starter dbvettez061
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Honda Service News 03-08
MIL On With DTC P0171 or P0172? Check for an Aftermarket Air Intake
Currently Applies To: ’03–08 Accords, ’06–08 Civics, ’07–08 CR-Vs, ’07–08 Elements, and ’07–08 Odysseys
Got a vehicle in your shop with the MIL on and either DTC P0171 (fuel system too lean) or DTC P0172
(fuel system too rich)? Check to see if the vehicle has an aftermarket air intake system. If it does, you’ve
probably found the culprit.
Aftermarket air intake systems can throw off the MAF sensor, causing either of these DTCs to set. Even
worse, they can cause serious engine damage, which is not covered by warranty! (For more info, take a
look at “Cold Air Intake Systems and Low-Restriction Air Filters: A Word to the Wise” in the April ’05 issue
of ServiceNews.)
The airflow characteristics of these aftermarket systems can vary from one to the other. The MAF sensor
provides feedback to the PCM to get the proper air/fuel ratio. If the long term fuel trim exceeds the
specified limits, the PCM will set one of those DTCs. Check out the Advanced Diagnostics in ISIS for the
specific DTC limits of the vehicle that you’re working on.
If the vehicle’s got an aftermarket air intake system, have the service advisor talk with your customer. He
or she can either have the air intake system returned to stock (and return later if the DTC comes back), or
he or she can take up this problem with the maker of the aftermarket air intake system.
Of course, if the vehicle already has a stock air intake system . . . then it’s high time to troubleshoot.
Honda Service News 04-05
Cold Air Intake Systems and Low-Restriction Air Filters:
A Word to the Wise
Cold air intake systems and low-restriction air
filters are hot aftermarket accessories. Popular
among the import tuner crowd, these items may
improve engine performance by letting the
engine breathe more deeply, reducing the intake
air temperature, and cutting down on weight. And
for that all-important sound when you wind up
the engine, cold air intake systems help produce a
deep, throaty tone.
Stock air intake systems are designed to clean the
intake air, minimize intake noise, and keep water
from getting into the intake tract, all the while
putting out the most horsepower and torque.
Although cold air intake systems and lowrestriction
air filters kick up engine performance a
notch, they also have their dark side. They can
really mess up the engine, and that’s not covered
by warranty!
With cold air intake systems, you run the risk of
engine damage from hydrolocking if you drive in
wet weather or plow through standing water.
These systems are usually designed to draw air
from the bottom of the engine compartment or
from the front of the radiator where the air is cold
and dense. The air filter used in these systems
doesn’t sit in an air box, so water that gets sucked
into the filter gets sucked right into the engine.
When enough water gets into the engine, the
piston can’t fully compress the air/fuel mixture
(water doesn’t compress) so it stops before
reaching top dead center (TDC). Even though the
piston stops, the crankshaft just keeps turning
from inertia. As a result, the connecting rod bends
and gets shorter. With each compression and
power stroke, the connecting rod flexes until it
eventually fails from metal fatigue.
With low-restriction air filters, you run the risk of
premature engine wear and contamination. Some
of these filters just don’t work as well as stock air
filters do. Microscopic debris can get past the
filter, causing premature wear of the pistons,
piston rings, cylinders, and valves. It can also foul
up the throttle body and the components of the
intake manifold runner control (IMRC), intake
manifold tuning (IMT), and idle air control (IAC)
systems.
So what’s the bottom line here? Tell your
customers they’re taking a really big risk if they
run the vehicle with a cold air intake system or a
low-restriction air filter. Engine damage caused by
these items isn’t covered by warranty, and that
could take a big bite out of their pocketbook.
MIL On With DTC P0171 or P0172? Check for an Aftermarket Air Intake
Currently Applies To: ’03–08 Accords, ’06–08 Civics, ’07–08 CR-Vs, ’07–08 Elements, and ’07–08 Odysseys
Got a vehicle in your shop with the MIL on and either DTC P0171 (fuel system too lean) or DTC P0172
(fuel system too rich)? Check to see if the vehicle has an aftermarket air intake system. If it does, you’ve
probably found the culprit.
Aftermarket air intake systems can throw off the MAF sensor, causing either of these DTCs to set. Even
worse, they can cause serious engine damage, which is not covered by warranty! (For more info, take a
look at “Cold Air Intake Systems and Low-Restriction Air Filters: A Word to the Wise” in the April ’05 issue
of ServiceNews.)
The airflow characteristics of these aftermarket systems can vary from one to the other. The MAF sensor
provides feedback to the PCM to get the proper air/fuel ratio. If the long term fuel trim exceeds the
specified limits, the PCM will set one of those DTCs. Check out the Advanced Diagnostics in ISIS for the
specific DTC limits of the vehicle that you’re working on.
If the vehicle’s got an aftermarket air intake system, have the service advisor talk with your customer. He
or she can either have the air intake system returned to stock (and return later if the DTC comes back), or
he or she can take up this problem with the maker of the aftermarket air intake system.
Of course, if the vehicle already has a stock air intake system . . . then it’s high time to troubleshoot.
Honda Service News 04-05
Cold Air Intake Systems and Low-Restriction Air Filters:
A Word to the Wise
Cold air intake systems and low-restriction air
filters are hot aftermarket accessories. Popular
among the import tuner crowd, these items may
improve engine performance by letting the
engine breathe more deeply, reducing the intake
air temperature, and cutting down on weight. And
for that all-important sound when you wind up
the engine, cold air intake systems help produce a
deep, throaty tone.
Stock air intake systems are designed to clean the
intake air, minimize intake noise, and keep water
from getting into the intake tract, all the while
putting out the most horsepower and torque.
Although cold air intake systems and lowrestriction
air filters kick up engine performance a
notch, they also have their dark side. They can
really mess up the engine, and that’s not covered
by warranty!
With cold air intake systems, you run the risk of
engine damage from hydrolocking if you drive in
wet weather or plow through standing water.
These systems are usually designed to draw air
from the bottom of the engine compartment or
from the front of the radiator where the air is cold
and dense. The air filter used in these systems
doesn’t sit in an air box, so water that gets sucked
into the filter gets sucked right into the engine.
When enough water gets into the engine, the
piston can’t fully compress the air/fuel mixture
(water doesn’t compress) so it stops before
reaching top dead center (TDC). Even though the
piston stops, the crankshaft just keeps turning
from inertia. As a result, the connecting rod bends
and gets shorter. With each compression and
power stroke, the connecting rod flexes until it
eventually fails from metal fatigue.
With low-restriction air filters, you run the risk of
premature engine wear and contamination. Some
of these filters just don’t work as well as stock air
filters do. Microscopic debris can get past the
filter, causing premature wear of the pistons,
piston rings, cylinders, and valves. It can also foul
up the throttle body and the components of the
intake manifold runner control (IMRC), intake
manifold tuning (IMT), and idle air control (IAC)
systems.
So what’s the bottom line here? Tell your
customers they’re taking a really big risk if they
run the vehicle with a cold air intake system or a
low-restriction air filter. Engine damage caused by
these items isn’t covered by warranty, and that
could take a big bite out of their pocketbook.
I have an 03 Corolla S with 360,000 km on the clock. It has had a K&N since about 6 months old, as have all my other cars. In reality, I always pick up 1.5-2 mpg on average, when I install the K&N.
There are many naysayers, but I have had zero problems with them and I routinely run them 500,000 to 600,000 km before selling the car.
There are many naysayers, but I have had zero problems with them and I routinely run them 500,000 to 600,000 km before selling the car.
Originally Posted By: DC_Stewart
I have an 03 Corolla S with 360,000 km on the clock. It has had a K&N since about 6 months old, as have all my other cars. In reality, I always pick up 1.5-2 mpg on average, when I install the K&N.
There are many naysayers, but I have had zero problems with them and I routinely run them 500,000 to 600,000 km before selling the car.
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
I have an 03 Corolla S with 360,000 km on the clock. It has had a K&N since about 6 months old, as have all my other cars. In reality, I always pick up 1.5-2 mpg on average, when I install the K&N.
There are many naysayers, but I have had zero problems with them and I routinely run them 500,000 to 600,000 km before selling the car.
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
If these filters really increased MPG why don't they come on cars from the factory.
With the CAFE standards, which will only continue to go up, manufacturers would certainly put a $40-50 filter on each vehicle to increase their fleet average if the filters work. $50 per vehicle is well worth it if it equals 1-2 MPG better.
With the CAFE standards, which will only continue to go up, manufacturers would certainly put a $40-50 filter on each vehicle to increase their fleet average if the filters work. $50 per vehicle is well worth it if it equals 1-2 MPG better.
Originally Posted By: dbvettez061
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
I'd like to know the same thing. Any car built in the last 15+ years will have a closed loop fuel system to match incoming air with the correct amount of fuel based on a predetermined program. If I want to go faster I make it possible for more air to get into the engine by opening the throttle plate and the computer will do its job by matching that additional air with more fuel. Last I checked letting in more air/fuel was BAD for gas mileage. Now if I have an air filter that (supposedly) allows more air through for any given throttle setting how exactly does that make my gas mileage go up?
I'm skeptical of just about ANY gas mileage claim. There are so many different factors that getting a useful number to go along with any given small tweak is IMPOSSIBLE! I might believe it if I saw a change in engine efficiency with the engine running on a dyno stand but not in the car on the road. How else do you control for tire tread & pressure, wind speed & direction, temperature, humidity, insolation, speed, stop lights, traffic or driver's mood?
Calvin
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
I'd like to know the same thing. Any car built in the last 15+ years will have a closed loop fuel system to match incoming air with the correct amount of fuel based on a predetermined program. If I want to go faster I make it possible for more air to get into the engine by opening the throttle plate and the computer will do its job by matching that additional air with more fuel. Last I checked letting in more air/fuel was BAD for gas mileage. Now if I have an air filter that (supposedly) allows more air through for any given throttle setting how exactly does that make my gas mileage go up?
I'm skeptical of just about ANY gas mileage claim. There are so many different factors that getting a useful number to go along with any given small tweak is IMPOSSIBLE! I might believe it if I saw a change in engine efficiency with the engine running on a dyno stand but not in the car on the road. How else do you control for tire tread & pressure, wind speed & direction, temperature, humidity, insolation, speed, stop lights, traffic or driver's mood?
Calvin
Love my Amsoil EaA that replaced the K&N (thankyou Pablo). I know the filtration is better and it looks a million bucks.
thanks for the head's up on k&n...i was going to get one, but it sounds as if it's easier to just change a standard filter out every 12mos or so...i'd probably try an amsoil eaa filter, but one isn't made for my vehicle
Originally Posted By: dbvettez061
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
Two sources really:
1) Marketing.
2) Placebo effect.
My question to you is: if a K&N flows the same as a quality paper filter, where does the extra MPG come from??????
Two sources really:
1) Marketing.
2) Placebo effect.
Originally Posted By: kingrob
Quote:
Two sources really:
1) Marketing.
2) Placebo effect.
+
Quote:
Two sources really:
1) Marketing.
2) Placebo effect.
+
Originally Posted By: XS650
Originally Posted By: kingrob
Quote:
Two sources really:
1) Marketing.
2) Placebo effect.
+
From K&N
"Our automotive OE (original equipment) replacement air filters generally add 1-4 horsepower"
You'll never feel any performance gain at 1-4 HP but omehow some do.
As far as MPG increase,K&N doesn't mention that in their advertising.
K&N says-"We certainly understand why it is theoretically possible for a consumer to experience a mileage increase after installing a K&N air filter or intake system, however, we do not go so far as to make a general claim that our air filters and intake systems will provide an increase in mileage."
If a K&N improved MPG's,it would be all over their ads.
Originally Posted By: kingrob
Quote:
Two sources really:
1) Marketing.
2) Placebo effect.
+
From K&N
"Our automotive OE (original equipment) replacement air filters generally add 1-4 horsepower"
You'll never feel any performance gain at 1-4 HP but omehow some do.
As far as MPG increase,K&N doesn't mention that in their advertising.
K&N says-"We certainly understand why it is theoretically possible for a consumer to experience a mileage increase after installing a K&N air filter or intake system, however, we do not go so far as to make a general claim that our air filters and intake systems will provide an increase in mileage."
If a K&N improved MPG's,it would be all over their ads.
I have a K&N, and my mileage sucks....but thats because I like to hear the sound of the custom intake the filter is attached too. Personally, I have not cleaned or messed with the filter in 50k miles or so....as issues arise from over cleaning and oiling. That said, I have been looking to replace it with some of the new dry style filters, but the opportunity has not presented itself.
Do K&N's filter as well as paper elements? Of course not....you can see through a K&N for pete's sake. That said, does it cause an issue for most cars? No...I know lots of people with hundreds of thousands of miles on there car that proove this point. That said, fouled maf sensors are a common problem with any oiled filter....but thats mainly due to user error.
Do K&N's filter as well as paper elements? Of course not....you can see through a K&N for pete's sake. That said, does it cause an issue for most cars? No...I know lots of people with hundreds of thousands of miles on there car that proove this point. That said, fouled maf sensors are a common problem with any oiled filter....but thats mainly due to user error.
Maybe but they sure increase the SI (dirt) in your oil. Get an EaA instead
The interesting thing to take from this in this forum is that the opposite way is true too.
A dirty air filter will NOT have a big impact on your MPG either. You will just get a lower performing car. Perhaps this is a good way to force yourself to save gas, and turn your 200hp car into a 100hp gas sipper, if you can't trust your lead foot.
When gas prices were above $4, this was one of the more interesting myths that AAA found and made it's way onto the news cycle.
A dirty air filter will NOT have a big impact on your MPG either. You will just get a lower performing car. Perhaps this is a good way to force yourself to save gas, and turn your 200hp car into a 100hp gas sipper, if you can't trust your lead foot.
When gas prices were above $4, this was one of the more interesting myths that AAA found and made it's way onto the news cycle.
Last edited:
Originally Posted By: raytseng
The interesting thing to take from this in this forum is that the opposite way is true too.
A dirty air filter will NOT have a big impact on your MPG either. You will just get a lower performing car. Perhaps this is a good way to force yourself to save gas, and turn your 200hp car into a 100hp gas sipper, if you can't trust your lead foot.
When gas prices were above $4, this was one of the more interesting myths that AAA found and made it's way onto the news cycle.
LOL, yeah I wanted to scream every time I saw someone claim that having a clean air filter improves gas mileage. The LESS air that gets in your engine the HIGHER your mileage.
Calvin
The interesting thing to take from this in this forum is that the opposite way is true too.
A dirty air filter will NOT have a big impact on your MPG either. You will just get a lower performing car. Perhaps this is a good way to force yourself to save gas, and turn your 200hp car into a 100hp gas sipper, if you can't trust your lead foot.
When gas prices were above $4, this was one of the more interesting myths that AAA found and made it's way onto the news cycle.
LOL, yeah I wanted to scream every time I saw someone claim that having a clean air filter improves gas mileage. The LESS air that gets in your engine the HIGHER your mileage.
Calvin
Clean air filter improves gas mileage is a fact. Comparing a car with a clogged air filter after 100k miles of used and with new air filter, the same car with new air filter does improve gas mileage by up to 10% according to many study, including US Dept. of Energy (http://www1.eere.energy.gov/consumer/tips/monthly_tips.html)
If you look at the link, the study they quote is:
Check & Replace Air Filters Regularly
Replacing a clogged air filter can improve your car's gas mileage by as much as 10 percent. Your car's air filter keeps impurities from damaging the inside of your engine. Not only will replacing a dirty air filter save gas, it will protect your engine.
--------------------------------------------------------------------------------
Air filter savings based on: Organization for Economic Co-operation and Development (OECD), 1981, Automobile Fuel Consumption in Actual Traffic Conditions. Paris, France.
These tests were performed before the introduction of computer-controlled, fuel-injection engines. Oak Ridge National Laboratory is currently studying the fuel economy effects of clogged air filters on more modern engines.
1981! and from France. The even admit that fuel economy on modern engines is currently being tested.
When gas actually got expensive last summer, Consumer Reports actually went and tested it recently, and found no noticeable difference in modern cars, hence at best you can consider this tip only partially applicable to old cars.
There is no downside to changing your air filter, so you might as well do it to get the best performance out of your car, but don't claim that it will significantly improve MPG at least here in the geekdom that is BiTOG. "Up to 10%" might mean 0.00001%. DoE is just simplifying the facts to the general public instead of boring their audience describing the differences between a car with ECU or non-ECU cars and because there is no downside to doing this proper maintnence.
http://www.consumerreports.org/cro/cars/...el-dollars-406/
Can you show a second study that is more recent then this one, or other report that did an independent test with an actual modern car and is not just quoting the DoE website?
Check & Replace Air Filters Regularly
Replacing a clogged air filter can improve your car's gas mileage by as much as 10 percent. Your car's air filter keeps impurities from damaging the inside of your engine. Not only will replacing a dirty air filter save gas, it will protect your engine.
--------------------------------------------------------------------------------
Air filter savings based on: Organization for Economic Co-operation and Development (OECD), 1981, Automobile Fuel Consumption in Actual Traffic Conditions. Paris, France.
These tests were performed before the introduction of computer-controlled, fuel-injection engines. Oak Ridge National Laboratory is currently studying the fuel economy effects of clogged air filters on more modern engines.
1981! and from France. The even admit that fuel economy on modern engines is currently being tested.
When gas actually got expensive last summer, Consumer Reports actually went and tested it recently, and found no noticeable difference in modern cars, hence at best you can consider this tip only partially applicable to old cars.
There is no downside to changing your air filter, so you might as well do it to get the best performance out of your car, but don't claim that it will significantly improve MPG at least here in the geekdom that is BiTOG. "Up to 10%" might mean 0.00001%. DoE is just simplifying the facts to the general public instead of boring their audience describing the differences between a car with ECU or non-ECU cars and because there is no downside to doing this proper maintnence.
http://www.consumerreports.org/cro/cars/...el-dollars-406/
Can you show a second study that is more recent then this one, or other report that did an independent test with an actual modern car and is not just quoting the DoE website?
Last edited:
Although most modern cars have no appreciable fuel economy difference with high flow filter/intake, eg, my 03 accord, my old 04 cavalier 3spd auto had a 10% increase in fuel economy between 85 and 115 km/h (95% highway) ~33mpg to ~37mpg The combination of the warmer air (more efficient combustion) and less restriction made a pretty significant difference. I took a lot of long trips with the car so the $30 investment i spent on my short ram filter (not a k&n) (after market filter on stock pipe) paid for itself in a couple of months.
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