Mustang GT and K&N air charger

>>> or . This is a reprint of a Consumer Report >>> article. Here is the relevant portion ->>>

If it had no impact then that is what they would have said. If it had no measurable impact then that is what they would have said. I have never stated what amount of impact the dirt would be on gas mileage as a filter became dirty. Only that it would have a negative impact on mileage that would become more noticeable over time as the filter collected more dirt. The CR statement doesn't invalidate my statement at all. It actually confirms it. Are you saying that CR is stating a dirty filter has NO impact on fuel economy?

>>> or . This is a reprint of a Consumer Report >>> article. Here is the relevant portion ->>>

What we are talking about is if a dirty filter affects gas mileage. It does. The degree to which it affects it depends on how much dirt is in the filter. A more efficient engine requires the throttle to be open less to make the same amount of power. If the throttle is opened less then less gas is used and the doesn't have to be under a greater load to perform its tasks.

Depending on the application, a K&N filter and/or intake system MAY improve mileage by making the engine more efficient. It depends on how efficient the stock intake system is it replaces. I would be willing to bet a K&N would flow better than a stock paper filter if each one had

30k miles on them and that toward the end of an OEM filters life the difference in gas mileage between them would be in the K&N's favor.

In your statement above you admit a dirty filter has an impact on mileage. I never said the impact was significant across a filters recommended life but only that it did occur to some degree. Maybe the degree is less than what one would see on an engine with a carburetor but it is still there.

The small farmers around my home town have tractors still in use that were manufactured in the early 1950s. One thing that really decimated the family farms in the Midwest in the late 1970s and early 1980s was when the banks urged the farmers with paid off land to leverage it to buy more land at inflated prices. Then when the land prices fell the very banks that talked them into the loans called them in because they no longer had the collateral to cover them. It slaughtered thousands upon thousands of family farms and really started the era of corporate farming in earnest. I commend you for sticking it out this long. IMO, farmers never do their jobs for the money. They do it for the love of farming.

Clearly you don't understand how modern fuel injection systems engines work. One last time - The output of the engine is dependent on how much air can be pulled into the cylinders. The amount of air drawn into the engine is controlled by the total intake tract restriction (filter, piping, throttle plate, valves opening, etc.). As long as you are not at wide open throttle, to achieve a particular power output, an increase in the restriction of one part of the system is compensated for by a change in the throttle position. The total restriction is the same for a given power output at a given rpm. The only sensor that is even slightly affected by minor changes in air filter flow restriction is the throttle position sensor. As I have pointed out repeatedly, this is just a gross position indicator. It is incapable of providing the sort of precise data that would indicate the minor change in the throttle position necessary to compensate for a slight difference in the flow resistance related to the air filter. The rest of the sensors used to control the amount of fuel injected will not be affected by reasonable differences in air filter restrictions (I am not talking about a completely plugged filter).

How does it make the engine more efficient????????????????????????????? It may allow the engine to pull in more air when the throttle is at wide open throttle, but this does not mean the engine is more efficient. It just means the engine can develop more power. And, if you take advantage of this extra power, you may actually reduce your fuel economy.....

I am willing to wager there would be no detectable difference. Unless you are at wide open throttle, the amount of air needed to maintain a give power output (or speed under a give set of conditions) is going to be the same. If the K&N filter is less restrictive than the paper filter, it just means the throttle plate will be slightly less open. The total intake tract resistance will be the same.

Which statement was that? Do you mean when I said - "But if we are just talking about filters operating in the normal range of contamination one would expect to see for a properly maintained engine, then the air filter is a not going to have a significant effect on fuel economy. And I stand by my statement that there is no reason to expect a K&N air filter to provide a significant (= measurable) improvement in the fuel economy of a modern fuel injected engine [compared to a reasonably well maintained paper filter]."

Significant = measurable (in my mind). A dirty air filter on a carbureted engine will have a measurable impact on fuel economy. However, even for a carbureted engine it has to be really dirty. I never let one get dirty enough to cause a problem, but I understand the sound reasons why a dirty filter could affect a carbureted engine's fuel economy. For modern fuel injected engines, there is no sound engineering reason to think that at air filter that is changed at reasonable intervals will affect fuel economy. The nature of the modern fuel injection systems eliminates the reasons why filter contamination affects fuel economy. The difference in air flow between a K&N and a paper filter is trivial in most cases. It is certainly a non-factor in regards to fuel economy.

Ed

*WELCOME TOOOO... CODGER-FEST... 2008!!!*

Care to share with the class?

Nah, I'm enjoying watching you and Ed tap dance from one end of the stage to the other. :oP

There's pieces that I agree with on both sides. Except the farming. I don't know nothing bout no farming. Never had an interest in a hoe.

I think we are really saying the same thing. We are differing on the definition of significant impact.

If you're farming with a hoe then you are living in the Third World. ;)

Careful, you may hurt her feelings....

Then that would be a Ho.

I was really looking forward to you picking out the mileages were the air filter was changed...

Ed

I never said the variation in mileage was great over the recommended life span of the filter. Only that there is variation. There are many other things that can effect mileage more so your numbers don't show anything unless you let the filter get very dirty. Even the time of year you buy gas affects mileage more than many things can. I can go through an refute every point you made but I've already done it so what is the use of doing it again? We have beat the horse, it is dead and now it is starting to look like hamburger.

I guess you are right, it is just a shame to see someone who can't grasp basic facts. All of your arguments seemed to depend on large variations in air filter restriction. A K&N provides a trivial improvement, certainly down in the noise range as far as the PCM of a modern fuel injected engine is concerned. Even K&N admits that a dirty K&N won't flow as well as a clean paper filter (see

). You can't seem to grasp the idea that for any sort of reasonable air filter restriction, the source of the total intake restriction (filter, plumbing, throttle, valves) is all that matters. If the air filter is a little more restrictive, then the throttle is just a little more open and the total air flow is the same. You seem to hang your whole argument on the throttle position sensor. I completely refuted this claim by providing you with the reference values for a Mustang TPS. No other sensor will even be slightly affected.

Good luck.

Ed

Here is a cold hard fact..... gas mileage deceases as an air filter becomes more restricted. If you plotted mileage verses the degree of filter restriction the resulting line would not be linear. Under light clogging there is little impact but as the filter efficiency decreases substantially so does mileage. You are confining you argument to the small zone where the air filter is still operating with a high efficiency. Even there, a trivial reduction in mileage is still a reduction. As the filter gets progressively dirtier the effect it has on mileage is further magnified.

Wow, what a response K&N causes! Bottom line, there's no way, no how that a panel air filter that fits a stock air box will add 15hp...even with the Mustang marginally sized filter box (which is identical to V6's). If any filter safely added 15hp, every car manufacturer in the world would use it!

The proof is in the pudding, so check out the excellent "Cold Score" article on the subject in 5.0 Mustang & Super Fords Magazine at

Engines are essentially an air pump. The more air in & out, the more fuel that can be ignited...and the more fuel, the more power. That is the scientific fact that K&N hangs on. However for a filter to determine the power output means it for one, the stock filter is the weakest link in the intake system (now wouldn't that be a silly engineering decision with all that goes into a modern engine?) and that increased air flow will automatically increase fuel demanded by the engine (while a carburettor would siphon more gas with increased air flow, this just isn't the case with today's computer controlled fuel-injected engines.)

Today's Mustangs have elaborrate computer controls that need to be reprogrammed (i.e. a new "chip") in order to take advantage of added air flow. Otherwise increased air flow will simply "lean out" the critical air-fuel ratio. That isn't good. Lean AF ratio can harm the engine, and likely REDUCE power.

Furthermore, increased airflow through an indentically sized filter DEMANDS larger spaces in its mesh. Larger spaces means larger particles. Do you really want larger particles in your engine? It is far better to enlarge the filter's surface area (& retain the same level of filtration) to pass more air.

There's a reason Ford's SVT engineers went with a CAI to generate the added 15hp for the Shelby GT's & the upcoming '08 Bullitt. Don't believe the hype...and that includes the fanboys & haters too.

Maybe so, but repeating the same claim over and over does not impress me as much as seeing results of testing on a modern FIE engine would. Do you have a URL for such a test report? The URL you gave earlier did not contain any test data; only dogmatic statements.

Go find one yourself if it is that important to you. It isn't my job to do your research. Find me a reference that says a dirty air filter doesn't cause ANY DROP in gas mileage.

Ed, you are speculating on theory alone, where is your data on this? You are mistaken on this issue. There are volumes of data proving that improved air flow increases horsepower and fuel mileage in modern fuel injected automobiles. Do a simple web search the data is overwhelming. How the hell do you think a multi-billion dollar aftermarket industry consistently sells millions of air flow improvement parts? They can't all be snake oil...

My documented 2 mile per gallon fuel mileage increase was absolutely attributable to improved air flow from the K&N air filter, Your skepticism does not alter that. It is a known fact that most early Ford EFI mid 80's to late 90's cars indeed suffered from restricted intake air flow. As to carbureted engines, I have run K&N air filters on 302, 351, 429 and 460 carbureted engines, and never documented a fuel mileage increase. I have documented fuel mileage records for all of my vehicles. I keep track of each tank full of fuel for each vehicle I own in a small log book in the glove box, I have done so since my second car as a teenager. My mileage and maintenance records are NOT speculation.