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Old 06-07-2008, 09:42 AM   #11
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I don't understand the analogy, although I would like to.

The way I see it is this: The manufacturer must design the engine and intake to handle the huge amount of airflow required to make lots of power at high RPM. So, at low RPM, the only restriction in the intake should be the throttle plate, everything else should flow without restricting the air at all. If that's not the case then they've made a huge design flaw.
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Old 06-07-2008, 03:28 PM   #12
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I added a K&N filter to my wifes Accord and the mileage dropped about 1.5 mpg. I did add the filter right at the beginning of the summer, so the temperature difference might account for the 1.5 mpg drop. I ran the filter for about 5 months and put the old paper one back in and the mileage went back up. I considering putting it back in after the summer months to see if there really was a difference in filters. I have considered getting a K&N for my Prelude but I dont want to waste money on another one and it doent help the gas mileage. I also have one in my 06 GMC Sierra and the gas mileage increased by 1 mpg. So maybe it has something to do with the bigger engine.
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Old 06-07-2008, 04:43 PM   #13
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Originally Posted by theholycow View Post
I don't understand the analogy, although I would like to.

The way I see it is this: The manufacturer must design the engine and intake to handle the huge amount of airflow required to make lots of power at high RPM. So, at low RPM, the only restriction in the intake should be the throttle plate, everything else should flow without restricting the air at all. If that's not the case then they've made a huge design flaw.
thats basically it, they help the air flow better at high rpm's. low rpm's the air is moving so slow it doesn't make a difference.

now bigger engines need more air so they might see the difference at a lower rpm range.


heres a pic representation of why the first half of your gastank seems to last alot longer than the 2nd half



as you can see gastanks can be many shapes, i picked 2 easy ones lol

in the square one the first half of the tank has the exact volume as its 2nd half, meaning the first half will seem to burn the same rate as its 2nd half(same amount of fuel)

in the triangle the first half has alot more volume than its 2nd half so while the first half may last you ohh 200 miles. then once it gets below 1/2 a tank theres alot less volume in the 2nd half so you might only get 100 miles out of it...(hence why it seems your fuel consumption seemingly went really fast)



most trucks have a squareish shape while most cars have some kind of triangular shape or wedge shape so it fits up under the unibody car frame.
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Old 06-07-2008, 04:44 PM   #14
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more air only gets to the engine if you open up the restriction (throttle). every decent study I've seen shows the K&N flows about 1% better and filters 1% worse.

You're also assuming the scale on the gas gauge is linear and accurate. I've driven cars that ran out of gas with the needle 3 of it's width above the E tick mark (my old ford ranger... boy was that an embarrassing discovery). My moms car has 3-4 gallons left when the light comes on and the needle is 3 widths below the mark.
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Old 06-07-2008, 07:10 PM   #15
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thats also true every single one of those gauges are an estimate (yes including the speedometer)
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Old 06-07-2008, 08:35 PM   #16
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Originally Posted by kamesama980 View Post
You're also assuming the scale on the gas gauge is linear and accurate. I've driven cars that ran out of gas with the needle 3 of it's width above the E tick mark (my old ford ranger... boy was that an embarrassing discovery). My moms car has 3-4 gallons left when the light comes on and the needle is 3 widths below the mark.
When the needle is at empty on the Tracker it means empty. I've had the needle where it's sitting right in the empty tick and filled up with 17.2 gallons in a 17.5 gallon tank. Making a turn a tad too fast the engine cut out and wanted to die right before the station.

The Cressida, however, used to read 1/4 tank below empty and still have a gallon or two left.
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Old 06-09-2008, 07:33 PM   #17
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???

I don't know about that....I could hear and feel the difference at idle and slow speeds with the K&N filter.

It's a pretty known fact in jeep circles that the 90's wranglers had a poor air feed. I wonder if this had an effect on the amount of mpg loss.


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I think this only matters at high RPM when you'r

e moving a lot of air. I suspect that there's no useful difference between the flow at the low RPMs that hypermilers use.



It's quite normal, actually. My brand new VW, which I never top off, does it. Every GM and Ford I've ever driven does it. The only reason I can think of for it is so that they can sell more cars when people say "My behemothmobile gets 200 miles to half a tank with aggressive driving".
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Old 06-09-2008, 08:09 PM   #18
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I don't understand the analogy, although I would like to.

The way I see it is this: The manufacturer must design the engine and intake to handle the huge amount of airflow required to make lots of power at high RPM. So, at low RPM, the only restriction in the intake should be the throttle plate, everything else should flow without restricting the air at all. If that's not the case then they've made a huge design flaw.
Paper filters are very effective, and cheap...
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Old 06-09-2008, 08:30 PM   #19
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I added a K&N filter to my wifes Accord and the mileage dropped about 1.5 mpg. I did add the filter right at the beginning of the summer, so the temperature difference might account for the 1.5 mpg drop. I ran the filter for about 5 months and put the old paper one back in and the mileage went back up. I considering putting it back in after the summer months to see if there really was a difference in filters. I have considered getting a K&N for my Prelude but I dont want to waste money on another one and it doent help the gas mileage. I also have one in my 06 GMC Sierra and the gas mileage increased by 1 mpg. So maybe it has something to do with the bigger engine.
On my 94 EX Accord, I added a cheapo ebay intake, and then added a one of those chrome straight thru mufflers, and my car got about 2 mpg better! But that was with my foot in it....
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Old 06-09-2008, 09:54 PM   #20
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thats also true every single one of those gauges are an estimate (yes including the speedometer)
Had an '85 Lincoln Continental which had a digital fuel gauge reading in gallons (or liters). It was rarely off by more than about a gallon or so...
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