The dirty air filter thread..

[MeiserT]

Post them up.

Here's mine....

Hard to believe the difference in fuel economy after putting in the new filter.
(some may contest that a clean air filter makes no difference in fuel economy, but from my experience.......... it does )

Still contemplating a K&N cold air intake. But for now I will stick with the $10 disposable.

http://i48.tinypic.com/9qzkms.jpg

[sourkeys]

What about just cleaning out the old air filter.

Last time I got my oil changed they said I could save 15% of my fuel mileage if I changed it but also told me it was going to be about 70 bucks.

[poedua]

Post them up.

Here's mine....

Hard to believe the difference in fuel economy after putting in the new filter.
(some may contest that a clean air filter makes no difference in fuel economy, but from my experience.......... it does )

Still contemplating a K&N cold air intake. But for now I will stick with the $10 disposable.



No it doesn't.....it's a myth.

From Consumer Reports regarding air filters and fuel economy........




" FUEL ECONOMY MYTH BUSTERS

A dirty air filter

Our tests show that driving with a dirty air filter no longer has any impact on fuel economy, as it did with older engines. That's because modern engines use computers to precisely control the air/fuel ratio, depending on the amount of air coming in through the filter. Reducing airflow causes the engine to automatically reduce the amount of fuel being used. Fuel economy didn't change, but the Camry accelerated much more slowly with a dirty filter "

http://www.consumerreports.org/cro/2012/01/fuel-economy-save-money-on-gas/index.htm



Corroborated by the U.S. Department of Energy ).......




6 MYTHS ABOUT SAVING GAS


Change your air filter regularly

Myth: The air filter in your car is designed to keep dust and dirt out of your motor in order to maintain performance, so keeping the filter clean will keep your motor running efficiently, right? Wrong.

Fact: Many of us change our air filters on the recommendation of a mechanic, usually when we get an oil change. However, modern air filters are actually designed to work more efficiently when dirty, using the dust and dirt as an added filter layer. A 2009 study conducted by the U.S. Department of Energy found that a dirty air filter had no effect on gas mileage in modern cars using fuel-injection technology. The study does say a dirty filter may result in acceleration difficulty and therefore shouldn't be left in place indefinitely. An air filter should be changed after about 48,000 km. "

http://www.cbc.ca/news/technology/story/2012/04/05/f-fuel-economy-myths.html

[feidailo]

some cars with maf housings shouldnt use k&n or other oiled filters because the oil can screw up the maf sensor.

[thelefteyeguy]

recently changed a 2.5 year old cabin filter...mother of god it was disgusting...even had flies and bees on it :lol:

[l69norm]

No it doesn't.....it's a myth.From Consumer Reports regarding air filters and fuel economy........

I'll argue that it does, but somewhere in between. The problem with those studies are they are right only for relatively steady state conditions where the car's fuel injection system is in closed loop operation. The O2 sensor is used to adjust the mixture as said in the article

As soon as you push the gas pedal more than a bit, the fuel injection system on most cars goes into open loop operation where the computer ignores the O2 sensor and uses predefined tables/curves that are stored in the flash memory at the factory Those stored tables assume that the air filter is relatively clean.

[MeiserT]

No it doesn't.....it's a myth.



Like I said, some will argue that it does not make a difference.

In my world, I gain about 25-30km on a tank driving the same dusty route daily, driving the same speeds and same habit of driving.

Non the less, post em up..
Let's see those dirty air filters... :razz:


What about just cleaning out the old air filter.


Tried before with the same type filter.... Failed miserably. :lol:
Easier just to spend the $10 once or twice per year.

[DavidY]

Personally, I would try to avoid Fram air filters as much as possible....AKA those orange filters.

My vehicle's manual specifies a change in air filters every 20,000 km...so I have it changed every 20-25,000 km.

Dave

[Pete_Coach]

No it doesn't.....it's a myth.

From Consumer Reports regarding air filters and fuel economy........


http://www.consumerreports.org/cro/2012/01/fuel-economy-save-money-on-gas/index.htm
Corroborated by the U.S. Department of Energy ).......

[B] [/INDENT]
http://www.cbc.ca/news/technology/story/2012/04/05/f-fuel-economy-myths.html
+1 It has been a myth for a long time.
It is curious though at how many people will disagree or argue with the data. The examples you show are totally unbiased. They have nothing to gain or lose with their data. Why would they publish the data if it is untrue? They have nothing to sell.
I guess some people have to believe in something to justify their buying unnecessary stuff.


some cars with maf housings shouldnt use k&n or other oiled filters because the oil can screw up the maf sensor.
The oil does cause problems with the MAF sensor and it is difficult to clean properly. Problem is people do not oil the filter as they should and naturally over oil. that makes the problem worse. But hey, it sounds good eh? LOL.

[mbk.2k3]

what maintenance do you need for k&n's?

do you use the liquid solutions to clean the air filter?
or do you buy a replacement filter?

i thought it was the latter, but the instructions kit says to use the solutions/liquids to clean the filter ...

:s

[ichpen]

what maintenance do you need for k&n's?

do you use the liquid solutions to clean the air filter?
or do you buy a replacement filter?

i thought it was the latter, but the instructions kit says to use the solutions/liquids to clean the filter ...

:s

Water. Wash from inside out. Dry. Apply small drops of oil as instructed.

Start car. Blip throttle a few times. Remove filter and spray some maf/circuit cleaner on sensor. Then reattach filter.

Having changed a billion k&ns I've noticed that even preoiled brand new quite a bit of oil is ingested and it does get on the maf. Hence why I clean it after the first load.

On a side note I've never seen a maf sensor permanently ruined. All of them do need a thorough clean when an overoiled filter is used.

[poedua]

I'll argue that it does, but somewhere in between. The problem with those studies are they are right only for relatively steady state conditions where the car's fuel injection system is in closed loop operation. The O2 sensor is used to adjust the mixture as said in the article

As soon as you push the gas pedal more than a bit, the fuel injection system on most cars goes into open loop operation where the computer ignores the O2 sensor and uses predefined tables/curves that are stored in the flash memory at the factory Those stored tables assume that the air filter is relatively clean.

Well, the U.S. Department of Energy study I referenced earlier used ' wide open throttle ' tests as part of their methodology ( per below ).

Does that constitute " pushing the gas pedal more than a bit " ?


" Wide-open throttle (WOT) tests were used to measure the changes in the filter pressure drop (Outlet DP). In a real-world application, the vacuum needed to set one of the air filter indicators would likely occur under heavy acceleration, such as merging onto an interstate, or climbing a steep grade. Therefore the level of restriction was set, using an artificial clogging technique described below, to achieve the desired Outlet DP during a WOT acceleration from idle to approximately 85 mph or a steady-speed (SS) WOT test in which the dynamometer was held at a fixed speed, 65 mph, and the throttle was held open for 10 seconds. Using these test procedures, the 2007 Buick Lucerne was configured to achieve an Outlet DP of approximately 7.0 kPa under the WOT acceleration and approximately 5.7 kPa under the SS WOT. Once the method for achieving this restriction was developed, it was used with each vehicle. Using this approach, the V8-equipped Dodge Charger showed a slightly higher Outlet DP than the V6 Lucerne, and the I4 Camry showed a slightly lower Outlet DP. The 1972 V8 Pontiac was restricted in a similar manner and level. It is important to note that all the modern vehicles used rectangular cartridge style air filters (Figs. 2.3 and 2.4), while the 1972 Pontiac used the cylindrical filter element common in that era (Fig. 2.5).

For all of the vehicles, a warm-up test was run before starting the WOT cycles. The warm-up cycle consisted of 5 minutes at 50 mph followed by 3 minutes at 30 mph. This 8-minute warm-up was always conducted on a warm engine (i.e., the engine had been run earlier that day). The acceleration WOT tests were run first, followed by the SS WOT tests. Five of each WOT test were conducted. The acceleration WOT tests used a procedure known as the modified Coordinating Research Council (CRC) E-60 protocol.12 The SS WOT tests were run by slowly accelerating the vehicle to approximately 65 mph, where the dynamometer control was set to hold a fixed speed. Once the vehicle speed reached 65 mph, the operator held this cruise condition for 10 seconds then opened the throttle to the WOT position for another 10 seconds. The vehicle was then brought back to idle for 30 seconds, and the process was"

[l69norm]

From memory, that testwas used to measure pressure drop on the filter. It does not monitor fuel consumption.

If you go right to the report conclusion, it says wording something like "for closed loop operation"

[poedua]

That test measures pressure drop on the filter. It does not monitor fuel consumption.

Actually, I wasn't asking about pressure.

I was wondering if ' wide open throttle ' tests constitute a form of " pushing the gas pedal more than a bit " - do they ?

[l69norm]

No, read the text. They were using wot to measure pressure drop only ie how clogged the filter is as well as change in performance. They test mileage elsewhere.

[poedua]

No, read the text. They were using wot to measure pressure drop only ie how clogged the filter is ad well as change in performance. They test mileage elsewhere.

You're right , they must of tested mileage elsewhere, cause here's the actual 2009 gov't ( U.S. Department of Energy ) study conclusion that......dirty air filters has no significant effect on the fuel economy of the newer fuel injected vehicles



" 4.1 CONCLUSIONS

The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested.

Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS).

The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased.

The carbureted engine did show a decrease in fuel economy with increasing restriction. However, the level of restriction required to cause a substantial (10–15%) decrease in fuel economy (such as that cited in the literature3,4) was so severe that the vehicle was almost undrivable. Acceleration performance on all vehicles was improved with a clean air filter.

Once it was determined how severe the restriction had to be to affect the carbureted vehicle fuel economy, the 2007 Buick Lucerne was retested in a similar manner. We were not able to achieve the level of restriction that was achieved with the 1972 Pontiac with the Lucerne. The Lucerne’s air filter box would not hold the filter in place under such severe conditions. (It is believed that this testing exceeded the design limits of the air box.) Tests were conducted at a lower restriction level (although still considerably more severe than the initial clogged filter testing), allowing the air filter to stay seated in the air box, and no significant change was observed in the Lucerne’s fuel economy or the AFR over the HFET cycle.

Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy. However for older, open-loop, carbureted vehicles, a clogged air filter can affect the fuel economy. For the vehicle tested, the fuel economy with a new air filter improved as much as 14% over that with a severely clogged filter (in which the filter was so clogged that drivability was impacted). Under a more typical state of clog, the improvement with a new filter ranged from 2 to 6%. "

http://www.fueleconomy.gov/feg/pdfs/air_filter_effects_02_26_2009.pdf

[hystat]

Personally, I would try to avoid Fram air filters as much as possible....AKA those orange filters.
what brand do you recommend?

[Pete_Coach]

Personally, I would try to avoid Fram air filters as much as possible....AKA those orange filters.

My vehicle's manual specifies a change in air filters every 20,000 km...so I have it changed every 20-25,000 km.

Dave
Why? Is it the colour? :facepalm:
You do have some specific reasons and proof why Fram is no good?

[l69norm]

Run of the mill cheapie O2 sensors in most cars are narrow band so they can only accurately work at or near 14.7 air fuel mixtures (ie closed loop operation) When you need to accelerate, the mixture needs to be about 12:1 for drivability otherwise the engine will stall/stumble. The O2 sensor can't read that wide a range so the computer has to go open loop and use a predefined data table.

Anyway, it validates the methodology used by large fleet maintenance; follow the manufacturer recommended replacement cycle and only change the filter early if the is a performance or drivability concern

[ichpen]

Run of the mill cheapie O2 sensors in most cars are narrow band so they can only accurately work at or near 14.7 air fuel mixtures (ie closed loop operation) When you need to accelerate, the mixture needs to be about 12:1 for drivability otherwise the engine will stall/stumble. The O2 sensor can't read that wide a range so the computer has to go open loop and use a predefined data table.

Anyway, it validates the methodology used by large fleet maintenance; follow the manufacturer recommended replacement cycle and only change the filter early if the is a performance or drivability concern

The AFR range varies hugely between cars. It can be as rich as 10:1 to 13.5:1 at WOT, I've seen close to stoich also. It entirely depends on your engine compression, timing, tolerances, fuel type etc etc etc etc. There is no single AFR range or number suitable for all vehicles.

BTW open loop doesn't mean your air is not metered. The maf is always referenced, closed or open loop on stock ECMs.

As for recommended filters run stock. You can switch to k&n for a little extra noise and reusability if that takes your fancy.

[craftsman]

Why? Is it the colour? :facepalm:
You do have some specific reasons and proof why Fram is no good?

Probably due to the poor reputation of the Fram OIL filters in comparison to the better filters out there - lower build quality levels than WIX and others. However, it could be the case that the other brands are over engineered for their function...

[Pete_Coach]

Probably due to the poor reputation of the Fram OIL filters in comparison to the better filters out there - lower build quality levels than WIX and others. However, it could be the case that the other brands are over engineered for their function...
Yea, they do have a low end filter but, they also have several higher quality filters. Just like other manufacturers. The lowest end (cheapest) Fram filter was rated very poor but the others were good. Quite a few years ago there was an oil filter study. It is still linked to, quoted and referenced to this day. That base study is over 10 years old now and not all tests been updated (although some new filters have been added). Many things have changed since then.
Not defending Fram but just saying people just perpetuate old data or myths because they know no better (Fram actually invented the spin on filter). I mean, if there are shops out there that want to sell an oil change at $19.95 (or even $29.95), they surely can't stick in a $10 or premium filter, can they now?

[craftsman]

Not defending Fram but just saying people just perpetuate old data or myths because they know no better (Fram actually invented the spin on filter). I mean, if there are shops out there that want to sell an oil change at $19.95 (or even $29.95), they surely can't stick in a $10 or premium filter, can they now?

Exactly!

And at the end of the day, how many engines actually got damaged due to the poorer filter? I would say that many more engines got damaged due to not replacing the filter or getting the oil change done when they were supposed to!

As for the $19.95 oil change, I'm always surprised at the complaints - bulk oil, cheap filters, inexperienced staff... Expectations are high, while wallet is cheap. Of course, there are the others who will spend way more than needed on something that they shouldn't. I wonder how many premium filters and high end oils are put into low end cars (ie. cars worth less than $15,000)?

[Mark77]

Run of the mill cheapie O2 sensors in most cars are narrow band so they can only accurately work at or near 14.7 air fuel mixtures (ie closed loop operation) When you need to accelerate, the mixture needs to be about 12:1 for drivability otherwise the engine will stall/stumble. The O2 sensor can't read that wide a range so the computer has to go open loop and use a predefined data table.

Anyway, it validates the methodology used by large fleet maintenance; follow the manufacturer recommended replacement cycle and only change the filter early if the is a performance or drivability concern

I'd suggest that open loop operation is a lot rarer than you think -- we're talking about the brief periods in which an individual might absolutely stomp on the pedal. Not just routine acceleration. Even if, due to a restrictive filter, slightly extra fuel is commanded in for a few seconds -- that makes extremely little difference on the overall fuel consumption.

A more restricted filter will also tend to provide cleaner air, which may or may not have its benefits. That's the giant problem with the K+N filters -- they advertise better flowability, but they end up giving up a lot of their overall filtering efficiency. Silicon (ie: dirt) numbers tend to be through the roof on the K+N equipped vehicles in used oil analysis.

[l69norm]

I'd suggest that open loop operation is a lot rarer than you think -- we're talking about the brief periods in which an individual might absolutely stomp on the pedal. Not just routine acceleration. Even if, due to a restrictive filter, slightly extra fuel is commanded in for a few seconds -- that makes extremely little difference on the overall fuel consumption. ...

You are sort of right. I had some free time and was curious so I hooked up a graphing scan tool to a car and took a joy ride. 100% of the time, if the accerleration pedal was pressed just far enough to caused a downshift (not wot), the o2 sensor goes full rich for about 10 to 15 seconds.

Doing a normal acceration from a traffic light produced produced some very inconsistent results. About 50% of the time, the o2 sensor goes full rich for only a few seconds and returns to normal on the other side of the intersection. The other 50% of the time, it stays full rich for about a block or 2 . There are some other factors coming in play, even trying the exact same thing repeatly produced different results.

The interesting thing was on deceleration, the o2 sensor goes full rich for quite some time 15 seconds+, then goes full lean when the computer turns off the injectors.

I'm guessing I was in open loop for about 10% of the drive.

So, routine acceleration does cause open loop operation, but the time in open loop can vary.

[ottofly]

Good job. Lots of great info here. Very interesting and enlightening read.

I change mine yearly since I get OEM Denso filters from Amazon for $10 and they look dirty enough. Cheap insurance I guess.