Changing clogged up air filter doesn't improve gas mileage?

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  #1  
Old 07-07-06, 02:38 PM
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Changing clogged up air filter doesn't improve gas mileage?

I bought a new Fram air filter after seeing my was black and you couldn't hardly see light through it, even when held up to the sun or trying to shine a flashlight through it in a dark room.

But to be honest with you, my expectations of raising my mpg's by 10 mpg's wasn't there. The car was actually running well and didn't seem to lack power.

I read on the box it came in that it's possible one can gain performance with a new air filter. But there were no claims about increase in mpg! If the performance (I think it even stated horsepoewer can be increased) is increased...would not that automatically mean that there would be more power and less gas pedal would be needed to motor down the highway at the same speed? So then why did they leave that out? I don't believe that was no accident.

Is it because gas mileage increases can too easily be found out?, where something stated like 'increase in performance' is not as numerically easy to prove?

Then I got thinking about clogged up air filters in general. And how one person's might be clogged up with actual dust, where someone elses (like mine maybe) was black and appeared worse than it was and was actually "clogged" up with oil residue. And that got me thinking about oil-bath air cleaners.

...................................

To be fair to Fram: It could very well be that their claims are the industry standard. I did not see what other brands of pleated paper filters claimed.
 

Last edited by DaVeBoy; 07-07-06 at 03:56 PM.
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  #2  
Old 07-07-06, 05:01 PM
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a bit high

I think 10 mpg is just a dream for a clean air filter maybe .5 mpg. Good to keep it clean every LITTLE bit helps.
 
  #3  
Old 07-07-06, 05:12 PM
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I was joking about the 10 mpg. But even if one got an increase of ANYHING mpg (even .5 is something to consider at over $3 for gas)...then why would not the manufacturer make the claim of a mileage increase? Would not they be more prone to sell new air cleaners if they rightfully could make that claim?
 
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Old 07-07-06, 05:37 PM
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they assume

They assume that people would know this and also some companys have already made this claim K&N is one I can think of.
I dont think adding the words improves fuel mileage to the carton will improve sales that much and besides big companies like Fram make more then air cleaners and if you dig even deeper you will see Fram is just a spin off of a bigger company Allied Signal that is into many things including aerospace.
 
  #5  
Old 07-07-06, 06:18 PM
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The way I figure it, regardless of how dirty or clean the filter is, modern O2 feedback engines will always mix only the appropriate amount of fuel for the air drawn in to maintain the perfect ratio of air-to-fuel for combustion. A dirty air filter will only restrict the max rate at which air can be drawn into the engine. Dirty air filter --> less air --> less fuel --> less max power. All it can do is limit your max speed and acceleration. Hence, I agree with the claims on the box. If anything, you may get better mileage with a dirty filter.
 
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Old 07-08-06, 04:31 PM
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Originally Posted by Kestas
If anything, you may get better mileage with a dirty filter.
Gee. I think I may have thrown the old one out. Rats. My latest mileage read was 18.5 on my 91 Spirit which is not good. My next door neighbor has the same identical car and his last test 2days ago yielded 29.5 mpg. I carry more stuff in my car, and he only makes 4 stops on the way to work where he parks his all day... where I make 4 stops just in a bypass zone and then driving all over town during the day hitting stop lights, stop signs all over town, driving from one rental property to the next...we aren't really comparing apples here. BUT, for him to be getting 11 mpg more seems stiff. I would think maybe 3 or 4 considering the things I mentioned.

My car runs strong and does not miss. But I pulled my plugs the other day to read them and discovered that since the last pull , when I was getting about 23 mpg, that #1 and #2 have black soot on the insulator inside and #3 and #4 are good.

Maybe I should start to add some fuel injector cleaner as some others here have really bragged up the stuff. (I have throttle-body injection, but maybe this would help something.).

It appears that the fresh air intake system is open to the air filter as it should be.

The oxygen sensor may be a place to look also. I have done nothing to this car ever, (very reliable and I would buy a new one off the show room floor in a heart beat given the chance because you can so easily get to stuff in the engine!!) and it has almost 225,000 on it now and after seeing those plugs, (which other than the soot are still new looking), I cleaned the plugs, pulled the distributor cap (I had never even looked inside before) and cleaned the 4 prongs and did the same to the crust on the rotor. But, as I always suspect, I almost knew before hand that what I did wouldn't help in any way. And it didn't.
 
  #7  
Old 07-09-06, 11:49 AM
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What kind of plugs? How old are the plug wires? When was the last time the cap and rotor were actually changed? Has the throttle body ever been cleaned? Do you change your oil regularly? Every 3k? 7k? 10? Never?
Bily
 
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Old 07-09-06, 02:44 PM
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I think the plugs are your standard Autolites. The plugs themselves are in good shape. No rounded edges.

Then: No, no, and no. Maybe I changed the oil 20,000 miles ago. I have to add some periodically and it is not ink black. Plus I have added Lucas (an STP like honeyish stuff) to it.

Why should have have to replace the cap and rotor? I have a feeling nothing good would come of it. I hate just replacing parts for no reason. I feel like an idiot every time I do that and it doesn't help what I am trying to accomplish. I feel like I am beating the system when I simply clean up stuff and reuse them. Just like years ago how we used to file the points with a small fine file made for that. Or, how you coud put your spark plugs into a sandblasting machine at some of the auto parts stores that had them. I did clean up the contacts, where it fires at, so that bright brass shows, without any of that scuzzy crust on there any more. And even after I did that, I noticed no difference. Like I said, the vehicle runs strong and does not miss. But it's like two cylinders only, for some reason, are getting more fuel, which seems odd.

Won't fuel injector cleaner work?
 
  #9  
Old 07-09-06, 02:57 PM
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Ignition items are WEAR items and should be changed periodically.
You should ask your neighbor the same questions.
You should only use Champion plugs in Chrysler products as that is what was put in from the factory and what works best. Cap, rotor and wires are susceptible to failure as they wear and age. Oil change intervals are a heated debate across the board and im not going to get into that here or anywhere else, but 10k is a bit extreme, regardless of the circumstances. Removing the gum and varnish from your throttle body and cleaning the IAC are important steps in maintaning your vehicle.
I bet your neighbor does regular (moreso than you) maintenance on his vehicle.
Change your oil, tune your car with new components and remove and clean the throttle body and IAC. You will definately see a noticable difference afterwards.
Fuel additives and injector cleaners are merely snake oil. They claim to do so many things and may help in a vehicle that is new and properly maintained, but they are in no was a cure all. They are made to be added to your regular maintenance intervals. IE.... a bottle in the tank at every oil change, so on and so forth. If you follow the maintenance schedule you should notice that all major maintenance intervals also include an oil and filter change. The manufacturer of most vehicles recommends at least every 7500 miles for regular usage maintenance and 3000 for severe usage.

And by the way, the conditions in which you conduct your tests and experiments is crucial to getting matching results.
Billy
 
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Old 07-09-06, 03:21 PM
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From what I have seen, my neighbor does nothing to either of his vehicles until something breaks. But he does have one thing going for him: HIS 91 has about 75,000 fewer miles on his, I believe.

Regarding the fuel injector cleaner: Remember that poster who was having recent problems, and it was advised by someone here that he dump some in, and he did, and he posted back that his car was cured? And I commented that maybe it was a coincidence?
 
  #11  
Old 07-09-06, 03:24 PM
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I have to agree..... I have worked in the parts world as well and those things are literally all over the place and claim so many different things. They may help, but they are in no way a cure for an ailing vehicle.
Billy
 
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Old 07-10-06, 11:29 AM
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Originally Posted by Kestas
The way I figure it, regardless of how dirty or clean the filter is, modern O2 feedback engines will always mix only the appropriate amount of fuel for the air drawn in to maintain the perfect ratio of air-to-fuel for combustion. A dirty air filter will only restrict the max rate at which air can be drawn into the engine. Dirty air filter --> less air --> less fuel --> less max power.
You will lose gas mileage when you go full throttle and burn rich as heck because the ecu ignores the O2. with the lack of air because of a dirty filter you will have less power, hotter exhaust gases with more hc. and way lower mpg when compared to a clean air filter
 
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Old 07-10-06, 11:31 AM
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Originally Posted by DaVeBoy
Regarding the fuel injector cleaner: Remember that poster who was having recent problems, and it was advised by someone here that he dump some in, and he did, and he posted back that his car was cured? And I commented that maybe it was a coincidence?
I agree with the rate at which he responded it was a coincidence. But the injectors cleaner do work to keep the engine running in tip top shape.
 
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Old 07-10-06, 05:02 PM
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Originally Posted by snuckers99
I agree with the rate at which he responded it was a coincidence. But the injectors cleaner do work to keep the engine running in tip top shape.
So what you are saying is that you believe that fuel injector cleaners can help keep the gas from building up gum and stuff, but if it already has it bad, it really isn't going to work? At least not in a quick-fix sort of fashion?

Is your explanation sort of like how they have now come out with an automatic shower cleaner? And the manufacturer claims that it will keep a tub/shower/surround from getting deposits, and also claim that if the tub already has deposits, that it will clean it, but it will be over some time. Not right away.
 
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