Mustang GT and K&N air charger

C. E. White wrote:
> "Michael Johnson" > wrote in message
> ...
>
>> Does an engine under a heavy load run richer than one that is under a
>> light load? The ECU has load tables that it uses to help calculate what
>> it believes the optimum air fuel ratio should be taking into account the
>> conditions it thinks the engine is operating under. What the computer
>> thinks is optimum isn't always 14.7:1. The computer expects the
>> operator to keep the filters fresh and a dirty air filter makes the ECU
>> think the engine is under a heavier load and thus changes the target A/R
>> to run richer than normal. This in turn reduces gas mileage.
>
> Some of what you say is true, but your conclusion are wrong. As I said
> before, the throttle position sensor is the only sensor that will even show
> a minor variation as a result of a change in air filter restriction. And
> throttle position sensors are not precise at all. They are gross indicators,
> used primarily to communicate rapid changes in the throttle position (i.e.,
> mashing down or letting up) so the PCM will be able to temporarily enrich
> the mixture (mimicking the accelerator pump of a carbureted engine) or
> change the IAC setting to prevent the engine from stalling as the speed
> falls back to idle (like a dashpot).

Does the load tables in the ECU increase A/R as the load increases?
Does the throttle position sensor help the ECU determine the engine
load? Does a dirty filter require the throttle to be further open to
make the same amount of power as it does with a clean filter? Does
running the engine at a lower A/F decrease gas mileage?

>> ECUs
>> aren't clairvoyant and can determine the degree to which an air filter
>> is dirty. It only takes the input from ALL the sensors and using
>> preprogrammed tables makes A/F adjustments (and many other) to the
>> conditions it perceives the engine to be operating under. Determining
>> engine load is a very important component is what it uses to set the
>> target A/F at any given moment. This is why they put throttle position
>> sensors on engines nowadays. The new Mustangs are somewhat different in
>> that there is no longer a direct wire connection to the throttle plate.
>> The computer senses the position of the accelerator pedal and then
>> sets the throttle opening accordingly.
>
> Not just Mustangs are fly by wire. But again, you are missing the key truth.
> An air filter, even a used one, is a minor restriction comapred to other
> elements in the intake system. When crusing at a steady speed (say 60 mph),
> the air drop across the engine air filter is going to be less than 0.3 psi.
> The pressure drop across the throttle plate will be on the order of 7 psi.
> The difference in pressure drop between a clean K&N filter and a reasonably
> dirty paper filter is probably less than 0.1 psi. Is it your claim that this
> small change is going to upset the PCM so much that it can't maintain the
> proper fuel to air ratio? There will be a bigger difference in the pressure
> after the air filter if you drive the car from sea level to the top of a
> 5000 ft mountain that any change in pressure related to normal changes in
> the filter restriction. If you truly believe this, why doesn't installing a
> K&N upset the PCM parameters?

You are splitting hairs. An air filter can operate within parameters
for 15,000+ miles but it is progressively getting more resticted and
progressively decreases gas mileage. If you chose to you could drive
around without an air filter at all and you'll get better mileage that
if you used an air filter. EFI cars have BAP (Barometric Air Pressure)
sensors to allow for adjustment of A/F due to air density changes from
varying altitudes. This tells the ECU that the engine isn't necessarily
under an increased load because driving in high altitude areas requires
the throttle to be more open compared to near sea level driving.

The core question is does a dirty air filter decrease gas mileage? It
does. How much depends on the amount of dirt in the filter and its
restriction to flow. The highest rate of flow for an air filter is when
it is new. After that it decreases and therefore mileage decreases.
The reason is that as the filter gets dirty it causes the ECU to use
ever more richer target A/F ratios based on its hard wired load tables
in the program code because the throttle position has to be
progressively more open as the filter collects more dirt in order to
make the same amount of power.

>> I have a TwEECer chip in my '89 LX that lets me program almost all of
>> the EEC-IV operating parameters. I know load tables exist and they
>> affect A/F as do many other sensor readings. There is a lot more going
>> on in the ECU than reading air in and making a simple computation for
>> fuel required. Things like engine acceleration rate, load, etc. come
>> into play in a big way. When something like a dirty air filter causes
>> readings of the throttle position sensor to be out of the range it
>> expects for a given driving condition then gas mileage can, and will, be
>> affected. The computer doesn't know the air filter is dirty and tries
>> to run the engine in a manner that isn't optimum for gas mileage. It
>> thinks you are doing something like climbing a hill, or accelerating,
>> and delivers fuel accordingly.
>
> Again, the throttle position sensor is just a gross indicator. The change in
> the position of the throttle related to normal variations in air filter
> restrictions will be trivial at cruise speeds. As the throttle angle changes
> from 4 degrees to 90 degrees, the tps ratio of output voltage to input
> voltage will go from around 0.2 to 0.98. The accuracy of the output is on
> the order of +/- 20%. There is no way a reasonable change in the restriction
> of the air filter is going to cause a greater change in the output of the
> TPS than normal variations inherent in the design of the tps. Automotive
> throttle position sensors are not highly accurate. And the PCM is able to
> use the feedback from the O2 sensor to compensate.

The throttle position readings are much finer than you think. The load
tables (there are more than one) in the ECU have numerous rows and
columns to read from. Going from 0.2 volts to 0.98 volts is is a large
range when you are reading to the hundredth of a volt. If the air
filter restriction is enough for the ECU to jump just one slot then
mileage has been decreased. There are enough "slots" that it can read
for the gradual drop in mileage to be imperceptible from one tank of gas
to the next. However, if you compare mileage over a greater time
interval you can see a difference. Most people use visual inspection to
determine when the filter gets changed and not mileage decreases. If it
looks dirty then it is probably time to change it before the mileage
decrease becomes too high and/or noticed.

>> The A/F doesn't remain constant across the entire load range an engine
>> can experience. As the load increases the target A/F decreases. This
>> is programmed into the load data tables of ECUs. If the A/F didn't
>> decrease then cylinder temperatures would get too high and start melting
>> things like piston tops.
>>
>> To further make my point does an engine get better gas mileage going
>> downhill or uphill at the same speed? Is that because in one condition
>> the engine is under a heavier load than the other? If the rpm rate is
>> the same for each condition then why is the mileage different? It is
>> because the throttle has to be open more going uphill to get the air
>> necessary to make the power needed to overcome the elevation increase.
>
> Ths had nothing to do with wether or not the air filter restriction has any
> affect on fuel economy.

Yes it does because a dirty air filter mimics the engine being under a
load from the viewpoint of the ECU. That is how the ECU reacts and why
gas mileage falls.

>> The data tables for engine load the computer uses are very specific to
>> the size of the throttle body put on the car. It relies on these tables
>> in conjunction with throttle position readings to determine what target
>> A/F is used from the load table. It also uses the O2 readings to fine
>> tune the A/F but only to meet the target A/F from the load table. A
>> dirty filter requires an increase in throttle opening which triggers the
>> computer to operate from the higher end of the load tables. Hence the
>> engine runs richer and gets lower mileage.
>
> The change in the throttle opening related to normal changes in air filter
> restriction is trivial. You are talking about gross changes that are far
> from normal.

If you change the air filter before it gets too dirty then you won't
notice the small decrease in gas mileage that occurs over the filter's
useful life. What happens to gas mileage when you fail to change the
air filter on a timely basis?

>>>> I'm not saying a K&N filter will give a noticeable improvement in gas
>>>> mileage over an OEM unit but with all things being equal the engine with
>>>> a more efficient filter will perform better. Do you think an engine
>>>> with a dirty air filter would pass an emissions test? If so then why
>>>> not?
>>> As long as the filter is in good shape, it will have no significant
>>> effect on the ability to pass an emissions test. See above for the
>> So if the filter is dirty enough then it will affect whether the
>> emissions test is passed? This means the A/F ratio isn't optimum,
>> doesn't it? If what you are saying is true then the computer should
>> compensate and make the A/F optimum thus allowing it to pass the test.
>
> Exactly. I can certainly imagine cases where a filter that is severely
> contaminated could cause a modern fuel injected vehicle to fail an emissions
> test, but this would be an exceptional case. For any reasonably well
> maintained vehicle, with an air filter changed per the manufacturers
> recommendations, you aren't going to fail an emissions test because of the
> air filter. If you want to hypothesize a very restrictive filter, all bets
> are off.

So you are agreeing that a dirty filter does decrease gas mileage (or
effect emissions) and the degree it is decreased depends on how dirty
the filter may be?

>>> reasons. I won't argue that a K&N might provide a slight performance
>>> increase at WOT. It very well might. But for anything but large throttle
>>> openings, the throttle plate is by far the most significant restriction
>>> in the intake tract. The filter is almost not there as far as air flow is
>>> concerned until the throttle is nearly wide open. Again, I am only
>>> talking about modern fuel injected engines. For older carbureted engines,
>>> a restrictive air filter would definitely significantly reduce fuel
>>> economy. And the situation is not clear to me if you are talking about
>>> some of the early speed density type fuel injection systems (systems
>>> without a MAF). For normal sorts of air filter restriction the PCM of
>>> these types of systems would be able to compensate for a restrictive air
>>> filter. However, for a very restrictive filter, they may not. However, as
>>> far as I know, no one has sold a car with a speed density only system for
>>> a decade.
>> You keep saying for "normal sorts of air filter restrictions" when a
>> restriction is a restriction. A filter just doesn't not affect mileage
>> one day and then suddenly becomes dirty enough to affect it the next.
>> It is a gradual progression that happens continuously and in most
>> circumstances is too slow for the driver to perceive.
>
> By normal, I mean real world situations. Again, if you want to theorize
> about some wacky almost plugged filter, then all bets are off. Once again -
> unless you are operating near wide open throttle, any restiriction in the
> intake related to the air filter is trival compared to the restriction of
> the throttle plate.

As an air filter becomes dirty it gradually decreases mileage. It is a
trade-off between acceptable mileage decrease and the economics of
changing the filter. In the era of quick lube places checking filters
with an oil change, most people never have an air filter get so clogged
that it causes a drastically noticeable change in mileage or black smoke
coming out of the tail pipe. None the less, gas mileage does decrease
over the life of an air filter.

>> Also, the basic operating parameters of an engine doesn't change because
>> it is fuel injected and computer controlled. The computer actually
>> mimics the old carburetors, governors, points etc. by using sensor
>> readings. The ECU controlling today's engines isn't a HAL 9000 that
>> thinks like a human. If it is getting garbage input from the sensors
>> then it spits garbage out to control the engine. The effect of a dirty
>> air filter on a fuel injected engine is the same as one with a
>> carburetor. On both engines the dirty filter puts the engine under load
>> and it is this that decreases gas mileage in both cases.
>
> THINK!!!!!!!!!!!!!!!!!!!!!! Why does a dirty filter impose any more load on
> an engine than a partially closed throttle plate. Do you understand
> carburetors? Do you know why they have a choke plate in front of the
> metering jets. Do you understand how the choke enriches the mixture. Can you
> see why for a carbureted engine a dirty filter might act like a choke and
> affect the mixture. Don't you understand that none of this applies to modern
> fuel injected engines? Carburetors depend on the Bernoulli principal to
> meter fuel. The fuel in the bowl is under atmospheric pressure. The pressure
> in the venturies is related to the flow through the venturies. If you place
> a restriction in front of the venturies, you will pull an artificially high
> vacuum in the venturies (higher than created by the Bernoulli principal),
> drawing more fuel into the air stream. Anything (like a choke, or a plugged
> air filter) affects the balance between the pressure on the fuel in the fuel
> bowl and the pressure in the venturies will affect the fuel to air ratio.
> This is why a clogged air filter can greatly affect the fuel economy of a
> carbureted engine. A fuel injected engine determines the amount of fuel my
> measuring a lot of parameters. None of these parameters is going to be
> significantly affected by normal variations in the filter restriction.

You are giving too much credit to an ECU's ability to "think". It
operates from tables and not from computing Bernoulli's Principle
thousands of times a second. It reads sensor data, looks up a value(s)
from a table and then outputs commands based on those table values.
Those tables don't take into account a dirty air filter in any way. If
the air filter is dirty enough to cause the throttle to be more open
then it can only read this input as the engine being under a load. Then
is reads from the load table to run at a lower A/F ratio. This
decreases gas mileage. Sometime by a little and sometimes by a lot
depending on how dirty the filter may be. The ECU doesn't have "the
filter may be dirty" parameter anywhere in its programming.

>>> By the way, the DIY Basics sight you referenced is loony
>>> (http://tinyurl.com/2hyeyx). You should follow your vehicle manufacturers
>>> replacement schedule for the air filter. I think that sight must be run
>>> by filter manufacturers.
>>>
>>> You should read these sites:
>>>
>>> http://www.visteon.com/utils/whitepa...05_01_1139.pdf
>> I searched the PDF for "gas mileage" "mileage" and "mpg" and got no
>> hits. It's a little too long for me to read through but it seems to
>> address filtering efficiency for removing particulates and not the
>> effect of dirty air filters on gas mileage.
>>
>>> http://www.filtercouncil.org/techdata/tsbs/89-3R3.html
>> This also seems to be addressing filter efficiency for removing
>> particulates and not gas mileage efficiency.
>
> True. I just thought you might find it interesting. They were meant to
> refute the idea that it was a good idea to change filters based on the
> advise at the DIY Basics site you referenced. I thought it was bad advice.

They all want you to replace consumable parts more often then needed.
That makes them more money.

>>> Air filters (paper and K&N) are less efficient at removing dirt when they
>>> are new. As the accumulate particles, the filtering efficiency improves.
>>> So changing your filter too frequently (or cleaning your K&N too often)
>>> can actually increase engine wear. You should also consider that K&N
>>> filters loads up with dirt much faster than paper filters (they have less
>>> dirt holding capacity). So while they may enjoy a flow advantage when new
>>> (or when just cleaned), the advantage decreases rapidly with time.
>> I have no doubt that a K&N filter lets more particulates by (and
>> therefore more air itself) than an OEM filter. Where the debate starts
>> is whether is has any appreciable impact on engine longevity for the
>> average vehicle. I believe it doesn't based on my own experience. My
>> '89 LX had had the same filter installed for over 130k miles and I had
>> the heads off at around 150k miles and saw no appreciable cylinder wall
>> wear. It also doesn't noticeably use any more oil than when it was new.
>>
>> The air filter debate is similar to the synthetic verses conventional
>> oil debate. IMO, there is no appreciable difference in wear from using
>> any oil that is changed every 3,000-4,000 miles. The contaminants never
>> get a chance to build up in the oil to cause a problem whether the oil is
>> synthetic or conventional.
>
> This time I am not trying to debate how well a K&N filter "filters." I am
> only arguing that there is no reason to expect a K&N filter to increase the
> fuel economy of a modern fuel injected engine (compared to a paper filter in
> reasonable condition).

It depends on if the K&N flows enough for the ECU to think the engine is
under a lighter load than when using an OEM filter. If it does then
mileage will increase. I would guess that a K&N would decrease mileage
at a slower rate than an OEM filter would because it will flow more air
if both filters receive the same amount of dirt. Whether it is
noticeable is up for debate.

On Jan 15, 10:00 pm, Michael Johnson > wrote:

> >> That's because the overall specific energy of E10 is less than pure
> >> gasoline. This is why going to biofuels is a horrible idea, IMO. We
> >> use up our top soil

> > Using proper farming techniques, top soil will last forever.

> It just won't stay in the same place. Erosion from farms is far worse
> than from land development activities.

Erosion doesn't happen with proper farming techniques.

> Top soil can be depleted to the point it can't grow much which is why farmers so much
> fertilizer to their land.

No and no.

Again, using proper farming techniques top soil won't be depleted.

Farmers use fertilizer much the same way people use vitamin pills.
Farmers abuse the soil and then rely on the "quick fix", just like
people eat wrong and then relay on the "quick fix" of vitamin
pills.

> >> to fill our tanks and at the same time increase the cost of food
> >> substantially.

> > No it won't. It'll promote farming, which in turn will keep our top
> > soil from being paved over/ruined. To cut your food costs, just cut
> > out the convenience -- i.e. eating out, packaged meals, etc.

> It has already increased food prices world wide. The UN's food budget
> is going through the roof because of the demand of biofuels.

That's only because production (farming) hasn't caught up with the new
demand. Just add more farms, or switch to other crops for
biofuels.

> http://yaleglobal.yale.edu/display.article?id=10167

> >> I would rather eat for a reasonable cost than fill up my tank

> > Remember to add in to your calculations the cost of you/us to keep the
> > Middle East stable.

> ... or to keep a nuke from going off on the Mall of Washington, DC.

You don't stop terrorism with war. War causes terrorism.

> >> with something that gives me less mileage, for about the same
> >> cost, than evil old 100% gasoline.

> > We have to cut our dependence on oil. (We've needed to since the
> > 70's.) The demand for/cost of oil is only going to intensify in the
> > future with so many counties becoming industrialized. And with this
> > increased demand there's going to be added pressure to control the
> > spicket. This means at some point a couple/few of the big boys -- US,
> > China, Russia, India, or some other nuclear country -- is going to get
> > into a fight and the results won't be pretty.

> IMO, we are heading in the right direction. It is just too slow for my
> liking. China and India has eight times our population and just think
> how much oil they will consume if they develop even half as much as we
> have today. We have no option but to change. The funny thing is I
> think the general population in the USA wants it and is ready for it but
> our government can't get their **** together to make it happen.

Agreed.

> Countries can't fight each other anymore.

Can't or won't?

> Their will be no winners,
> only losers. It is one of the benefits of a global economy. If China
> blows us up who will buy their cheap goods and where will they get
> wheat, corn etc. to feed 1.5 billion people?

But if two counties begin fighting over the [oil] spicket because they
can't get enough to power their cars, heat their homes and run their
factories will cooler heads prevail?

> IMO, terrorism is a much
> bigger threat than war between nations.

I think terrorism will be the new low-level war technique. Just pay a
guy to strap on a bomb to get your nation's point a cross. Make sure
all the tracks are covered, later deny any involvement and then sit
back and reap the fallout.

Patrick

wrote:
> On Jan 15, 10:00 pm, Michael Johnson > wrote:
>
>>>> That's because the overall specific energy of E10 is less than pure
>>>> gasoline. This is why going to biofuels is a horrible idea, IMO. We
>>>> use up our top soil
>
>>> Using proper farming techniques, top soil will last forever.
>
>> It just won't stay in the same place. Erosion from farms is far worse
>> than from land development activities.
>
> Erosion doesn't happen with proper farming techniques.

The trouble is that 99% of farmers don't use those techniques and if
they did the impact of crop yields would be substantial.

>> Top soil can be depleted to the point it can't grow much which is why farmers so much
>> fertilizer to their land.
>
> No and no.
>
> Again, using proper farming techniques top soil won't be depleted.
>
> Farmers use fertilizer much the same way people use vitamin pills.
> Farmers abuse the soil and then rely on the "quick fix", just like
> people eat wrong and then relay on the "quick fix" of vitamin
> pills.

An example is that corn will deplete the top soil of nitrogen and
soybeans put nitrogen back into the soil. This is why these two crops
are rotated when and were possible. The trouble is that corn is more in
demand and generates more product per acre so they need to supplement
with fertilizer in order to plan corn year after year. The Midwest
enjoys a thick blanket of top soil that developed over the eons but it
is being reduced much faster than it is being replaced in heavily farmed
areas. I agree that there are ways to farm that can slow this process
down substantially but these methods usually result in lower yields and
most farmers won't use them for this reason.

>>>> to fill our tanks and at the same time increase the cost of food
>>>> substantially.
>
>>> No it won't. It'll promote farming, which in turn will keep our top
>>> soil from being paved over/ruined. To cut your food costs, just cut
>>> out the convenience -- i.e. eating out, packaged meals, etc.
>
>> It has already increased food prices world wide. The UN's food budget
>> is going through the roof because of the demand of biofuels.
>
> That's only because production (farming) hasn't caught up with the new
> demand. Just add more farms, or switch to other crops for
> biofuels.

This is where I have the problem. More planting means more fertilizer,
more erosion etc. Even then biofuels won't make much of a dent in our
oil import volumes or in meeting our energy needs. There is already an
impact on food prices and biofuels is in its infancy. It isn't only us
here in the USA that will be affected. We feed a large part of the
world and if we divert our food resources for energy production there
will be even more starving people in the poor areas than there are
today. If you think countries will fight over oil resources what do you
think they will do for food?

>> http://yaleglobal.yale.edu/display.article?id=10167
>
>>>> I would rather eat for a reasonable cost than fill up my tank
>
>>> Remember to add in to your calculations the cost of you/us to keep the
>>> Middle East stable.
>
>> ... or to keep a nuke from going off on the Mall of Washington, DC.
>
> You don't stop terrorism with war. War causes terrorism.

Do you think the Islamic extremists will stop trying to kill us if we
sit in the Lotus position and start singing Kum Ba Yah? I don't think
they will. We are talking about people that think "Honor Killings" are
perfectly acceptable. They chop off hands and feet for stealing. They
stone people to death for adultery. They treat women like slaves. Do
you really think they can be reasoned with? They push the Islamic
religion like the Soviet Union pushed communism. They are like the Borg
from Star Trek. If you don't convert to their belief system then you
need to be killed.

>>>> with something that gives me less mileage, for about the same
>>>> cost, than evil old 100% gasoline.
>
>>> We have to cut our dependence on oil. (We've needed to since the
>>> 70's.) The demand for/cost of oil is only going to intensify in the
>>> future with so many counties becoming industrialized. And with this
>>> increased demand there's going to be added pressure to control the
>>> spicket. This means at some point a couple/few of the big boys -- US,
>>> China, Russia, India, or some other nuclear country -- is going to get
>>> into a fight and the results won't be pretty.
>
>> IMO, we are heading in the right direction. It is just too slow for my
>> liking. China and India has eight times our population and just think
>> how much oil they will consume if they develop even half as much as we
>> have today. We have no option but to change. The funny thing is I
>> think the general population in the USA wants it and is ready for it but
>> our government can't get their **** together to make it happen.
>
> Agreed.
>
>> Countries can't fight each other anymore.
>
> Can't or won't?

Won't or can't the result is the same. Interests of countries today are
no longer bound by national borders.

>> Their will be no winners,
>> only losers. It is one of the benefits of a global economy. If China
>> blows us up who will buy their cheap goods and where will they get
>> wheat, corn etc. to feed 1.5 billion people?
>
> But if two counties begin fighting over the [oil] spicket because they
> can't get enough to power their cars, heat their homes and run their
> factories will cooler heads prevail?

Nuclear capable countries will fight each other over food before oil. I
think many in this country, including the government, know the end is
near for obtaining cheap oil. Hybrids are the first step in getting
plug-in cars to the consumer and when that happens and those cars have a
decent range we will see the dominoes fall real quick on the internal
combustion engine.

>> IMO, terrorism is a much
>> bigger threat than war between nations.
>
> I think terrorism will be the new low-level war technique. Just pay a
> guy to strap on a bomb to get your nation's point a cross. Make sure
> all the tracks are covered, later deny any involvement and then sit
> back and reap the fallout.

The problem with a nation making war is they have something to lose.
There is territory, infrastructure, population etc. that can be
destroyed or taken. Terrorists are nomads that have very little to lose
and are willing to die for their cause. It is also something that will
never go away. Fighting it is like playing an unending game of
Whack-A-Mole.

Michael Johnson wrote:
> C. E. White wrote:
>
>> "Michael Johnson" > wrote in message
>> ...
> The very fact that the farmer has to add fertilizer to the soil means
> the methods he deploys to grow crops depletes the topsoil of nutrients.
> What happens to his crops if no fertilizer is added? The other
> component is that typical modern farming techniques cause erosion on a
> massive scale.

Uh, not true. Modern farming means no-till farming, which causes far
less erosion than previous practices. For starters, see:
http://en.wikipedia.org/wiki/No-till_farming

--
Cheers, Bob

Michael Johnson wrote:

> Bob Willard wrote:
>
>> Michael Johnson wrote:
>>
>> None of those sites listed states that the effect of a dirty air filter
>> on gas mileage applies to FI engines with MAF sensors. It seems
>> rather likely
>> to me that those sites are merely repeating what was true with carburated
>> engines as still being true, without retesting or even remodeling.
>
>
> These web sites were developed after EFI was common place. The .gov
> site is from the US Dept. of Energy and is very current. The Edmunds
> site is also very current. The last one is put up by the State of
> Massachusetts. These aren't old out of date web sites. Do a Google
> search and you'll have weeks of reading that tells you that dirty air
> filters decrease gas mileage on ALL cars.
>
Oh come on, man. You know that the age of the web site does not
indicate the age of the content. So again, I ask: Do you have any
URLs for tests done with modern engines?

--
Cheers, Bob

Bob Willard wrote:
> Michael Johnson wrote:
>
>> Bob Willard wrote:
>>
>>> Michael Johnson wrote:
>>>
>>> None of those sites listed states that the effect of a dirty air filter
>>> on gas mileage applies to FI engines with MAF sensors. It seems
>>> rather likely
>>> to me that those sites are merely repeating what was true with
>>> carburated
>>> engines as still being true, without retesting or even remodeling.
>>
>>
>> These web sites were developed after EFI was common place. The .gov
>> site is from the US Dept. of Energy and is very current. The Edmunds
>> site is also very current. The last one is put up by the State of
>> Massachusetts. These aren't old out of date web sites. Do a Google
>> search and you'll have weeks of reading that tells you that dirty air
>> filters decrease gas mileage on ALL cars.
>>
> Oh come on, man. You know that the age of the web site does not
> indicate the age of the content. So again, I ask: Do you have any
> URLs for tests done with modern engines?

Do you have any? Feel free to make an effort. It's not my job to do
your homework to support your claims. I gave you my links now you give
me yours.

Bob Willard wrote:
> Michael Johnson wrote:
>> C. E. White wrote:
>>
>>> "Michael Johnson" > wrote in message
>>> ...
>> The very fact that the farmer has to add fertilizer to the soil means
>> the methods he deploys to grow crops depletes the topsoil of
>> nutrients. What happens to his crops if no fertilizer is added? The
>> other component is that typical modern farming techniques cause
>> erosion on a massive scale.
>
> Uh, not true. Modern farming means no-till farming, which causes far
> less erosion than previous practices. For starters, see:
> http://en.wikipedia.org/wiki/No-till_farming

Have you been to many cultivated fields lately? No-till farming has
been around for decades (far from being modern) and it still hasn't been
adopted by many serious farmers that are in it to make a profit. You do
know that the first step in no-till farming is to dump weed killer on
the fields to kill ALL the plant life before the crop seeds are knifed
into the soil?

My first job out of college in the early 1980s was with a local Soil and
Water Conservation District in Virginia and when we would mention
no-till farming to a farmer his eyes would roll. The reaction hasn't
changed over the years when the question is asked. It all sounds good
until the farmer sees the crop yields in the fall from a no-till field.
Farmers are businessmen much more than they are environmentalists.

****lots of previous stuff removed*****

I'll take one last stab at this.....

The basis of your argument seems to be that automotive engineers are idiots
who cannot design a fuel injection system that will compensate for a minor
difference in the flow restriction of an air filter. I don't believe this to
be the case.

I dug out the Ford shop manual for a 1999 Mustang 2V 4.6 Liter engine. The
PCD includes TPS reference voltage values for a 1999 Mustang 4.6L V-8 - At
idle the voltage is OK if it is anywhere between 0.52 and 1.27 V. At 30 mph,
the acceptable range is 1 to 1.2 V. At 55 mph the acceptable range is 1.2 to
1.5 V. Clearly the tps value is not a major determining factor in adjusting
the A/F ratio since the acceptable values at idle and 55 mph actually
overlap. No other sensor related to the A/F ratio are affected by the air
filter restriction. The only other sensors in front of the throttle plate
are the MAF sensor and air temperature sensor. Neither will be affected by
small changes in pressure in the intake tract related to the air filter
restriction. A 1999 Ford 4.6L does not utilize a barometric pressure
sensor.

The following sensor are part of the system:

Camshaft Position (CMP) Sensor -4.6L
Crankshaft Position (CKP) Sensor -4.6L
Throttle Position (TP) Sensor
Idle Air Control (IAC) Valve -4.6L, (2V)
Engine Coolant Temperature (ECT) Sensor -4.6L, (2V)
Mass Air Flow (MAF) Sensor -4.6L, (2V, 4V)
Intake Air Temperature (IAT) Sensor
Heated Oxygen Sensor (HO2S)
Catalyst Monitor Sensor
Clutch Pedal Position (CPP) Switch
Fuel Pressure Sensor

Except for the TPS, none of these will be affected by normal sorts of
changes in the air filter restriction. As I have tried to explain
previously, the TPS is just a gross indicator of the throttle position. It
is not designed to be used for the sort of fine A/F ratios you are
suggesting it is used for. The range of acceptable output valves for a given
throttle position is so wide that it cannot possibly be a determining factor
when evaluating changes in fuel economy as a result of changes in air filter
restriction.

The following is from the PCD manual for a 1999 Mustang:

-----

"Fuel Trim

The fuel control system uses the fuel trim table to compensate for normal
variability of the fuel system components caused by wear or aging. During
closed loop vehicle operation, if the fuel system appears "biased" lean or
rich, the fuel trim table will shift the fuel delivery calculations to
remove the bias. The fuel system monitor has two means of adapting Short
Term Fuel Trim (FT) and Long Term Fuel Trim (FT). Short Term FT is referred
to as LAMBSE and Long Term FT references the fuel trim table.

Short Term Fuel Trim (Short Term FT) (displayed as SHRTFT1 and SHRTFT2 on
the NGS tool) is a parameter that indicates short-term fuel adjustments.
Short Term FT is commonly referred to as LAMBSE. LAMBSE is calculated by the
PCM from HO2S inputs and helps maintain a 14.7:1 air/fuel ratio during
closed loop operation. This range is displayed in percentage (%). A negative
percentage means that the HO2S is indicating RICH and the PCM is attempting
to lean the mixture. Ideally, Short Term FT may remain near 0% but can
adjust between -25% to +35%.

Long Term Fuel Trim (Long Term FT) (displayed as LONGFT1 and LONGFT2 on the
NGS tool) is the other parameter that indicates long-term fuel adjustments.
Long Term FT is also referred to as Fuel Trim. Long Term FT is calculated by
the PCM using information from the Short Term FT to maintain a 14.7:1
air/fuel ratio during closed loop operation. The Fuel Trim strategy is
expressed in percentages. The range of authority for Long Term FT is
from -35% to +35%. The ideal value is near 0% but variations of ±20% are
acceptable. Information gathered at different speed load points are stored
in fuel trim cells in the fuel trim tables, which can be used in the fuel
calculation.

Short Term FT and Long Term FT work together. If the HO2S indicates the
engine is running rich, the PCM will correct the rich condition by moving
Short Term FT in the negative range (less fuel to correct for a rich
combustion). If after a certain amount of time Short Term FT is still
compensating for a rich condition, the PCM "learns" this and moves Long Term
FT into the negative range to compensate and allows Short Term FT to return
to a value near 0%.

As the fuel control and air metering components age and vary from nominal
values, the fuel trim learns corrections while in closed loop fuel control.
The corrections are stored in a table that is a function of engine speed and
load. The tables reside in Keep Alive Random Access Memory (RAM) and are
used to correct fuel delivery during open and closed loop. As changing
conditions continue the individual cells are allowed to update for that
speed load point. If, during the adaptive process, both Short Term FT and
Long Term FT reach their high or low limit and can no longer compensate, the
MIL is illuminated and a DTC is stored."

-----

And finally, here is a challenge for you. The chart below lists the average
fuel economy over 900 to 1250 mile intervals for my 2006 Nissan Frontier -
tell me approximately at which points the air filter was changed......should
be a piece of cake if filter restriction affect fuel economy as drastically
as you think. This truck is a farm vehicle and spends a significant amount
of time on dirt road and field paths. It probably saw more dust last October
than your Mustang has ever seen (I pick peanuts in October - almost nothing
generates more dust).

Cum. Avg
Miles MPG
Since previous period
------- ---------------------
1176 18.1
2132 18.9
3274 19.0
4234 17.9
5276 18.2
6433 17.2
7358 18.7
8488 18.9
9540 18.8
10666 18.1
11812 19.2
12888 19.3
13995 19.2
15230 18.6
16276 19.1
17425 19.0
18518 17.9
19454 18.6
20444 19.0
21375 18.1
22423 18.1
23543 18.4
24684 18.2
25684 18.8
26895 18.9
27889 19.3
29045 17.7
30199 19.3
31203 18.8
32151 20.1
33175 19.6
34236 19.7
35313 20.5
36396 18.9
37403 19.3
38325 19.6
39306 19.9
40275 19.5
41311 19.8
42494 18.6
43721 19.2
44685 18.2
45757 18.8
46686 18.8
47745 18.7
48456 19.3

Ed

"Michael Johnson" > wrote in message
...
> Bob Willard wrote:
>> Uh, not true. Modern farming means no-till farming, which causes far
>> less erosion than previous practices. For starters, see:
>> http://en.wikipedia.org/wiki/No-till_farming
>
> Have you been to many cultivated fields lately? No-till farming has been
> around for decades (far from being modern) and it still hasn't been
> adopted by many serious farmers that are in it to make a profit. You do
> know that the first step in no-till farming is to dump weed killer on the
> fields to kill ALL the plant life before the crop seeds are knifed into
> the soil?
>
> My first job out of college in the early 1980s was with a local Soil and
> Water Conservation District in Virginia and when we would mention no-till
> farming to a farmer his eyes would roll. The reaction hasn't changed over
> the years when the question is asked. It all sounds good until the farmer
> sees the crop yields in the fall from a no-till field. Farmers are
> businessmen much more than they are environmentalists.

Not only have I seen no-till fields - I have planted fields that way
(Northeastern NC). I would plant all my soybeans that way if I had a good
no-till drill. As it is, I borrow my neighbors no-till drill to plant beans
behind small grain. For my type of soil, I don't believe no-till is
appropriate for corn or peanuts. However one of my neighbors has been very
successful at planting no-till cotton. I don't personally raise cotton, but
if I did, I would no-till most of my cotton crop. The majority of winter
wheat in my area was planted no-till this year, and the majority of soybeans
planted behind the wheat will be no-till as well. If I had the proper
equipment I would try at least one field in no-till corn. I have a neighbor
who is trying it. I'll keep my eye on the results. If he is successful, I
would love to go that way. The saving in planting time alone would make it
attractive if the yields are within 10% of conventional planting. The
business man in me would love to save the time and money consumed by
conventional field preparation operations. The biggest thing holding me back
is the cost of new no-till equipment. Commodity prices have been so
depressed over the last 25 years that it is all I can do to maintain the
equipment I have. I haven't purchased a new farm tractor since 1991.
Converting to no till would cost me at least $100,000. If I thought the
current moderate prices would last, I would consider buying at least a
no-till seed drill and the larger tractor I would need to handle it. I have
little faith that the prices won't drop back to depression era levels
shortly. As I mentioned before, unadjusted corn prices last year were no
higher than in 1975. Adjusted for inflation, they were as low as during the
great depression. Only very large farmers can make a decent living farming
these days. I farm twice the acreage my Father did, with half the labor
(around 350 acres). He made his living farming and sent three children
through college and graduate school. I make barely enough from farming to
cover the payments on my farm land. I have a "real" job to support myself
and my children.

Ed

Ed White wrote:
> "Michael Johnson" > wrote in message
> ...
>> Bob Willard wrote:
>>> Uh, not true. Modern farming means no-till farming, which causes far
>>> less erosion than previous practices. For starters, see:
>>> http://en.wikipedia.org/wiki/No-till_farming
>> Have you been to many cultivated fields lately? No-till farming has been
>> around for decades (far from being modern) and it still hasn't been
>> adopted by many serious farmers that are in it to make a profit. You do
>> know that the first step in no-till farming is to dump weed killer on the
>> fields to kill ALL the plant life before the crop seeds are knifed into
>> the soil?
>>
>> My first job out of college in the early 1980s was with a local Soil and
>> Water Conservation District in Virginia and when we would mention no-till
>> farming to a farmer his eyes would roll. The reaction hasn't changed over
>> the years when the question is asked. It all sounds good until the farmer
>> sees the crop yields in the fall from a no-till field. Farmers are
>> businessmen much more than they are environmentalists.
>
> Not only have I seen no-till fields - I have planted fields that way
> (Northeastern NC). I would plant all my soybeans that way if I had a good
> no-till drill. As it is, I borrow my neighbors no-till drill to plant beans
> behind small grain. For my type of soil, I don't believe no-till is
> appropriate for corn or peanuts. However one of my neighbors has been very
> successful at planting no-till cotton. I don't personally raise cotton, but
> if I did, I would no-till most of my cotton crop. The majority of winter
> wheat in my area was planted no-till this year, and the majority of soybeans
> planted behind the wheat will be no-till as well. If I had the proper
> equipment I would try at least one field in no-till corn. I have a neighbor
> who is trying it. I'll keep my eye on the results. If he is successful, I
> would love to go that way. The saving in planting time alone would make it
> attractive if the yields are within 10% of conventional planting. The
> business man in me would love to save the time and money consumed by
> conventional field preparation operations. The biggest thing holding me back
> is the cost of new no-till equipment. Commodity prices have been so
> depressed over the last 25 years that it is all I can do to maintain the
> equipment I have. I haven't purchased a new farm tractor since 1991.
> Converting to no till would cost me at least $100,000. If I thought the
> current moderate prices would last, I would consider buying at least a
> no-till seed drill and the larger tractor I would need to handle it. I have
> little faith that the prices won't drop back to depression era levels
> shortly. As I mentioned before, unadjusted corn prices last year were no
> higher than in 1975. Adjusted for inflation, they were as low as during the
> great depression. Only very large farmers can make a decent living farming
> these days. I farm twice the acreage my Father did, with half the labor
> (around 350 acres). He made his living farming and sent three children
> through college and graduate school. I make barely enough from farming to
> cover the payments on my farm land. I have a "real" job to support myself
> and my children.

My guess is you have soil with a high sand content where no-till works
better. In other areas the soil is more compact and the plant's root
system has a much harder time propagating through the soil. In the
Midwest and here in Virginia it is very rare to see a no-till field.
Especially, on farms that require high production to be profitable. How
is your yield on the no-till compared to conventional till? I know the
cost to plant is supposed to lower but the rub is the yield is lower too.

When I was growing up in Indiana there were many full time farmers that
could make a living off of as little as a thousand tillable acres.
Nowadays someone farming 1,000 acres would barely scratch out a living
there. Farming became a corporate business a long time ago.