just got k/n drop in filter & w/two tanks run though my city/hwy avg. has gone from about 29.5-30.0 mpg to 31.5-32.5 mpg. if you ask me i think the 2-3 mpg increase was worth the$45 spent on the filter. If you think about it just say 2.5 mpg more *10 gal= 25 more miles than w/stock filter. which to me mean it will pay for itself in the long run. And i found out to get best results,which has worked on all the cars i've used them on,is to disconnnect the battery for 30 min or so after installing so thet way the computer can reset the air flow reader to adjust for more air coming into the engine. i'm getting better mpg & acceleration.

coo

But is it worth sucking all the extra crap into your engine? K&N and similar filter elements have been proven filter less than OEM paper type filters. Filters are a lot cheaper to replace than screwed up engines. "But, but, but... race cars and highly modded cars use them." Well, race teams tear down engines and rebuild them very often and highly modded cars usually aren't driven on a daily basis in all conditions. Do you plan on rebuilding your motor often? or baby it like a garage queen?

Marketing would have you believe everything is fine as long as money is leaving your wallet. It's better for your car to stick to the OEM filters. They are cheap enough to replace every 6 months or longer, depending on how much you drive and how dusty your environment is.

well to be honest w/you been running k/n for years never have had a problem. And ya i've seen all the chartes and figures.

Short of sucking a bird down into your engine a K&N air filter will not harm your engine....if you do your oil changes on a regular schedule. I am on the fence about K&N. I had one in a Ford Explorer Sport Trac for 7 years with no problems.......I sold it with 261,000 miles on it with no major repairs done to it and it did not burn any oil between the 5,000 mile changes. I got about 4 mpg better than anyone I personally knew with the same vehicle..same engine. I don't know if this was because of the K&N or the FlowMaster exhaust...or both.....or neither. I know a paper filter for the Versa costs 7 bucks...a K&N costs 60 bucks. I have read posts and reviews on this subject till I can't find anymore to help sway me.....one way or the other. If I could gain 2 mpg with a K&N I would do it....but I drive a lot and would recoup my money quickly. But I am still not convinced...am willing to listen to any ideas on this.

I put a K&N filter on my 07 Versa at 12,700 miles. In the 3000 miles I drove before I totaled the car I did not notice any change in MPG due to the filter. I salvaged the filter & at 10,000 miles I put it on the 08 Versa that replaced the totaled 07. In the 5000 miles since then my average MPG has gone up by .27 MPG. I attribute that to engine break-in more than the K&N.

well my avg results are comming from what i read on my scan gauge,thats how i know its avg atleast 2-3mpg more & like i put in my first post you have to disconnect the battery for about 30 mins to reset computer to read the more air flow coming into the engine.

I disconnected my battery like that to install an aftermarket stereo. I got a 2 tank spike in my MPG (Jan 08 in my Sig Pic), but over several thousand miles there wasn't much change. I really don't care what a scanguage shows, give us actual figures calculated by miles/gallons over several thousand miles.

i took a K and N off our 1995 BMW 318 as it was more trouble than it was worth. Cleaning it. Oiling it etc. I never saw any documentable proof of improved mileage. The city streets are not the right place for a controlled experiment. I did chip the 318 that improved the 2nd gear torque, but I am not aware those are available for the Versa.

The placebo effect.

well the placebo effect seem to work quite well then because every car i've put it in has gained atleast 2mpg, have one on my wifes x & it has gone from 16.5mpg to 19.0 on reg unleaded in city driving & ave 25.0mpg on hwy. hows that for placebo effect!

With new CAFE standards and the pressure for increased gas mileage, if manufacturers could get a 2 MPG increase by putting in a K&N filter, I guarentee every new car made would have a K&N filter from the factory.

I believe your 2 tank increase. I experienced the same thing after disconnecting the battery, but it had nothing to do with an air filter. Again come back with actual calculations after several thousand miles & let us know the results.

Consumers reports has done tests and found that not only do aftermarket filters not provide and improvement in mileage, that in fact a dirty OEM air filter does little to affect mileage... it only results in an decrease in power. The ECU in moderns cars keeps the fuel/air ratio optimal in any condition. Havign a dirty air filter simply makes hte engine think you're driving in high altitude. I know I've always gotten better mileage in higher altitude than lower.

So better air flow imporves power in some cases, but I think it's somewhat of a myth that effeciency is improved. You have to alter the engines internal design to really affect effeciency. You're airflow restriction is more often the CAT, valve size, and the cam timing. For more pwoer, you really need to raise compression and make the engine more square so it can rev higher (shorter stroke, more bore). Most engines are a compromise to both.

You want better economy, get a motorcycle. I averaged 43mpg on my last trip, with a passenger and 150lbs of luggage for camping. Even loaded down, I could still give most sports cars a good run under 100mph. I actually have more miles on my motorcycle this year than either of our cars.

I HAVE ONE QUESTION: WHY IS IT THAT SO MANY PEOPLE WILL BASH A K/N FILTER WITH THE "O WITH THAT ON THERE YOU WILL DESTROY YOUR ENGINE",BUT YET YOU HAVE THE PEOPLE W/THE CAI'S BUT YET THEY DONT HAVE SMACK TALKED TO THEM ABOUT THOSE THINGS! I'M SURPRISESD THE DON'T P/U TRASH & WATER AS LOW TO THE GROUND THE ARE! LET'S HEAR SOME BASHING ON THOSE! AND YES I'M A LITTLE PEEVED THAT WHY IT'S ALL IN CAPS!

You have to realize what an internet forum really is:under-informed folks offering opinions. Do they know what they are talking about? Sometimes, but more often they are not speaking from actual learned experience - more like a friend of a friend knew some guy that. . . . . . . .

I have been in the auto industry / auto racing area for over 40 years. K&N does make a good product. No they do not let dust thru - improper installation or improper sealing allows that.

Bravo on your choice, you "may" get less restriction, but the filter on our V's in not the bottleneck.

I have a K&N on the Camel... picked it up for $30 or 40 dollars new (yay coupon and free shipping)...

No thoughts on mpg increase... but I get really good mpg in the Camel. I'm thinking it may soon come time to clean the filter and I don't have the time... so I'll probably buy the OEM filter at my next oil change and bring the K&N home to clean at my leisure...

Just randomized thoughts...

i kept my old filter also just to have for when its time to clean k/n filter,but i think i myself have/had a point about what i said about people w/cai's.