I put one on my 09 base and got about 3 mpg better also a little more power when I'm mashing

 

Hate to revive old threads but hate to start pointless new ones...I just got a K&N drop in a few tanks of gas back and I saw consistently LOWER mpg (09 sport auto). In my 99% highway driving, I have been averaging about 34 mpg. If I TRY to use a little hypermiling technique, I get up around 40 fairly easy. With my first tank of gas after dropping in the K&N, I got 30 mpg. When I started trying to be more conservative, I got 32 at best. Last night, I switched my old paper filter back in. This morning, on a fresh tank of gas and not very conservative driving, I'm back to 34 mpg so far.

What gives? I could care less either way as all I really saw from the K&N was more noise, but I thought it was kinda funky that my mileage dropped.

 

I have a SSR with a K&N cone filter and actually noticed an increase in MPG. I get better throttle response, sounds better, and its a little more peppy. Based on the physics of an engine, being basically just an air pump... less restriction on the suck side would theoretically equal less strain on the engine, causing more power and less work being done overall right?... On the other side of that argument is that more air equals more fuel into the combustion chamber. The computer sees more air and wants to send more fuel to compensate for that. Just my theories. BTW in my old age it has become second nature to just throw on an intake or K&N drop-in in every car I own. Is this wrong forum?

 

No I would tend to agree with that premise and that's why, even though I knew there would be no real performance increase, I threw it in there in the first place. Just wondering if I could reset something by pulling the battery cable or something... I have a scangauge. I wonder if that would tell me anything if I hooked it up?

 

Oil analysis has proven that K&N allow more dirt to enter the engine and excess oil can cause issues with sensors. Yes, you may feel a little butt dino kick but safer to stick to your factory air filter IMHO. I keep my vehicles for ever and don't want to lose compression due to dirt.

 

No difference in my 2010 Fit. Just washable.

 

Consider the role of the throttle. This acts to restrict the flow of air into the engine. It doesn't make the engine "work harder." The engine burns the correct amount of fuel mixed with the amount of air allowed to enter. It used to be based on venturi action in a carburetor; now it's much more sophisticated. The engine doesn't care whether it's a paper filter or a metal throttle-plate restricting airflow.

All a less restrictive intake, whether it's a complete CAI or a drop-in high-flow filter, does, is to increase top end power. It will have no affect at anything less than full throttle. It might mean you need to open the throttle a bit less (accelerator pedal less depressed), but the amount of extra air the improved filter allows is only a small percentage compared to the action of the throttle. In any case, the extra air could only cause more fuel to be burned, if you took advantage of it (harder acceleration, more time at WOT).

But joule for joule of energy derived by burning fuel moving your Fit around, the air filter will have no affect on the amount of fuel burned; it always burns just enough.

On the flip side, there's no reason to get worse MPG, except your tendency to "put your foot in it" more with the expectation of a better performing intake.

Even K&N make no claim for increased MPG, just power. The amount of power might be noticeable.

 

maybe the with the increased airflow, the MAF sensor is signaling more airflow so it may be thinking that more gas is needed? my theory anyway.

 

i had one, got rid of it after I stalled out on a highway...more below

got towed to the nearest place, which happened to be a Honda dealership. They said oil from the KN filter got on the maf and killed it, the coil packs and the plugs...($1100)

I called KN up and they said the oil should never fly off the filter and to supply pictures. I went to the mechanic's bay and did just that. He then said use maf cleaner and see it that gets the car back up.

coincidentally the dealer did not have maf cleaer spray, just brake clenaer, which would kill my maf. So I went ahead with the repair and sent out my kn filter and coil packs for forensic analysis by K&N.

their results:

the coil packs were fine (so I have extras for later, Honda bastards) but the maf was fould by some oil other than a k&n filter oil (yeah right). Also the cotton afixed to the sensor was from something other than the kn filter...

Since I was noticing any gains in HP or MPG I put the OEM filter in and will occasionally throw in a kn filter after days of cleaning and drying

 

I had the K&N typhoon on my Fit for about 23k and cleaned/oiled it 3x's w/o a problem, ever! This also goes for other cars I've had in the past too, no problems. The thing that people have to remember is to follow the steps correctly when cleaning and more importantly, oiling them. You wait till its dry and then spray a single, light, even coat on the pleats and let it dry real good, like over night, that's it.

When looking for the filter, can't miss with Ebay, you may even find a used one, a good way to go IMO because they last forever

 

I've been using the K and N for the last 2 years and 25,000 miles. It got me better performance at the expense of more noise from the airbox. I'll take the noise. Performs great... no problems, so far. Worth the money. If I baby both car filters, the K and N will get me 1 mpg better on average... but, I don't baby the car any more... I enjoy the faster starts with my 09 MT. I never had any oil leaking from the filter that was noticeable. I know that when mice get in the airbox they can't eat through the K and N like they do with the OEM filter, so that's a big cost savings. I would recommend the K and N to anyone with the MT.

 

Air filter should not change the MPG if the car is in closed loop.
In closed loop the gasoline used is in a fixed ratio to the air coming in.

Some people say that air turbulence decreases the gasoline surface tension so that would optimize fuel burning ... I don't know... legend.
Some people say the opposite where smooth air flow is better.

But changing the air filter in a closed loop system should not make any difference.

 

True. The only reason to buy a K&N drop-in is to save money on air filters over the life of your car and get a couple groovy stickers. That's why I just bought one.

 

^^^same^^^

 

The dealer may be a crook for replacing the ignition parts, but K&N and its defenders ignore the obvious problems with fouled MAF sensors that happens to many, many people.

My theory on the person who posted a decrease in mileage with K&N is that the MAF wire was coated just enough to throw the mixture off, but not enough to throw a CEL code. In closed loop, the O2 sensor is supposed to correct, but if the two inputs are "fighting" the mixture may constantly vary, but within a range acceptable to the computer.

 

i bought the AFE drop-in air filter similar to K&N, when i switch back to the
factory air filter i actually notice an increase in MPG, I think your better off using the factory air filter

 

So after K&N returned the coil packs and filters with a report that the filter and packs were fine but the maf was infact fouled by an oily substance and a piece of cotton that did not belong to their filter I re cleaned the fillter, let it dry overnight (to be safe) and placed it back in the car along with an ultraguage.

My gas mileage has suffered lately and I am still tracking down the source (I have a leaking FI seal I need to replace soon) but noticed my Short term fuel trims and consequently my long term fuel trims were high

Short term range (-1 to 24 were the two extremes, usually was between 9-14)

long term would stay between 8-14


After driving with the filter for about 23,000 miles I decided to go back to factory to see if there was any difference. My short term returned to a normal range (-8 to 10) and long term are in single digits (for the most part).

I have to note my mileage for this past tank stayed the same.... will track after a few more tanks.

 

So after K&N returned the coil packs and filters with a report that the filter and packs were fine but the maf was infact fouled by an oily substance and a piece of cotton that did not belong to their filter I re cleaned the fillter, let it dry overnight (to be safe) and placed it back in the car along with an ultraguage.

My gas mileage has suffered lately and I am still tracking down the source (I have a leaking FI seal I need to replace soon) but noticed my Short term fuel trims and consequently my long term fuel trims were high

Short term range (-1 to 24 were the two extremes, usually was between 9-14)

long term would stay between 8-14


After driving with the filter for about 23,000 miles I decided to go back to factory to see if there was any difference. My short term returned to a normal range (-8 to 10) and long term are in single digits (for the most part).

I have to note my mileage for this past tank stayed the same.... will track after a few more tanks.

oh, the butt dyno registered no change in performance either.....

 

I have also read this. Yes they are a higher flow, but that is not necessarily a good thing. You have bigger pores that have oil sprayed all other them that are actually getting the dirt to stick to it, and that's how a k&n works.

I used to own a 1990 Taurus SHO, pretty quick car.... I also had a K&N filter. (This was actually a in fender CAI, so more exposed then just a drop in filter) Car started running rough one day, I posted to the the SHO forum and listed my mods and a few of the more technical members pointed to the maf sensor being dirty due to the oil filter. I took the sensor element out, cleaned it with electronics cleaner (It was pretty dirty actually) and then the car ran fine.

 

Oily stuff yuck