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Increased Mpg With Air Filter Change.


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I have waited for a few weeks to post this to make sure it wasn't a fluke.

Recently, I replaced the stock Denso air filter with a K&N drop in air filter. (takes about 5 minutes to do)

I was getting about 21 mpg around town, minimal highways, stop and go, you know the drill.

I change only the air filter and continue to drive the same. Over the four fill ups of gas (over 14 gallons each in the cousre of three weeks) since the filter change the new average has gone up to 24 mpg.

I am impressed.

For those interested, the K&N filter number is 33-2260 and cost $35 on line. (Pre-'02 ES have a different filter number.) The stores around here haven't stocked it yet. Shipping was another $7.00.


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truthfully the k & n is crap


the change made to your vehicle is probably contributed to a new filter

not it being a k &n

if you had replaced the filter with a regualr filter that was new i am pretty sure the same results would be expected

i had a k & n in 97 for 5 weeks

it was also my 8th week of ownership so i just made all my routine maintance,including just replacing with a new air filter 3 weeks before

i found 0 increase in performance

and 0 increase in fuel economy

sorry but the the gains are probably attributed to just that it is a new filter

plus when ever you get a new thing you always want it to work great even if it only does in your mind

i also had one on my moms grand prix

i was 16 hadn't gone to tech school yet and

hell stickers on my car made me feel kool like i modified my car still

lol ( the good ol days) anyway

i had one also on it and i thought it was great also

i never did control the variables like a new filter compared to an old filter to get a proper baseline of performance

this isn't just me trying to shoot down an idea just let you guys realize there are lot better things to spend the money on

like a motorvac you will save more money in gas in like 3 months


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skp, I totally DON'T agree with you on this.

If your were publishing an article in a mechanics trade magazine and I were the publisher, I would have to ask for your data to back up your statement of "the K&N is crap". Is your conclusion drawn solely from your personal experience?

In support of a K&N filter.

Previous experience:

The only reason I consisdered the K&N was because of a similar past experience. I had a very small increase in gas milage with an SSEi, but an increase nonetheless. It couldn't hurt.

Monetary savings:

1. For the price and mileage warranty, I never have to buy a filter AGAIN for the life of this car. That would be a savings about $150 in filters alone if I changed every 30k with Denso from the Lexus parts counter (calculated for 180k miles). A Denso filter is $28.41/ea at my dealership.

2. At an average of $1.85/gallon, that comes out to a savings of $4.00 per tank full that I will save from the increase of 21 to 24 mpg. Not much when paying at the pump each time, but this comes out to close to $300/year. Now multiply that by the expected life of the filter/car (let's say 10 years for easy math) and you get $3000.

Financial findings: ($150 parts savings + $3000 gas savings) = $3150 return on a ($35 filter + $8 cleaner/oil + $7 shipping) = $50 investment

Previous filter being dirty and replaced with new filter:

I think not, The Denso filter was changed on the 15k service at my request. So that means the filter that was changed out only had 5k miles on it. I would have changed to the K&N at that time, except the #33-2260 filter was not available until the middle of March 2003.

Actual data:

The total mileage driven on each tankful divided by the amount of gas pumped = 24.1 to 24.3 mpg on each tankful since the filter change.

The total mileage driven on each tankful divided by the amount of gas pumped = 19.9 to 21.8 mpg on various tankfuls from 9/7/02 and 10,500 mi to 3/2003 and 20,000 miles. Keep in mind, new Denso filter midway at 15k AND no change there.

There was no change in the way I drive or the conditions or locations that the car was driven in either.


No change in acceleration times that I can tell, but then again, I never measured them. It ain't a Viper or a Vette. It's a Lexus ES, its built for comfort and quality, not speed.


No change....nor did I expect there to be any, it was only a filter element change


Wasn't displayed/attached to the car, don't believe in them. I know what I'm packing.

Bottom line,

Try it on your next filter change, if you don't see an increase in mileage then go back to the Denso filter. In reality, the Denso is only $8.00 less than the K&N.

skp, you didn't shoot me down.....your shot missed.

My data and experience speak in favor of a K&N filter if one so chooses.

have a good evening all.


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sorry stevie i didn't mean to sound like i was trying to shoot you down at all in any way shape or form

i think that last answer was just splendid

with absolutly no sarcasim implied

i guess i am not anywhere to as detailed as that to posting

not really trying to make an article

just a quick thought

i really just base the filter on k&n from my experiance with my previous cars

and other shop owners who sell there products

it is better for economical reasons period

by the reduction of replacment costs of reg filters to me it stops there

if you are looking for performance gains there is none

which is what it is marketed as mainly

and that is what i meant to say

when i read you first post it made it seem to anyone who may not have alot of experiance with k&n that it is the main reason for the increase of milage , i still don't belive in drop in's

i gave away mine to my cousin,he saw no difference ,then i got a free replacment of it

and still no difference ( he does have a 3jz though)

a cai is much better for flow still can be washed and increases the gas milage by 10%+ if made correctly for the right car

i went from 475km a tank to 550km

and i am trully sorry if you saw my comments as an attack in anyway

just my opinion on a product that i feel fleeces people for performance gains

but atleast gets gas milage with yours

it usually takes 1/2 to all of the (recharger kit) app depending on size and imbedded dirt

so you would add almost the price of a stock filter each change or cleaning

also i don't think cross linking is against the other forum rules just no ebay ones

but out right links might be as previously noted

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consider hands shook. ;) You just caught me off guard.

By the way, a recharger kit is $8.00 on line, $10 at Autozone and it will last for 2 to 3 cleanings and recharges. K&N recommends cleaning and recharging every 50K miles.


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I have to agree with skperf. on this one. The increase that may happen in HP will most likely not even be noticable. You will get an increase in MPG although they do come at a price. SK filters are performance filters, which means they are made differently from your regular filters. They let a lot more air through but they also let a lot more dirt in as well. They are nowhere near the filtering ability of the regular filter. You are letting a lot more and a lot bigger particles through. So, while you are seeing temporary MPG increase, you are effectively ruining your engine in the long run. To me it is ABSOLUTELY not worth it. And I may get flamed for this, but if you are looking for performance, ES300 is probably not the best place to start. I love my car, but I got it b/c its quiet, smooth and comfortable. Not because its 210 horses make my blood boil. :)

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the original post was simply a statment about an increase in gas mileage. That's all. Absolutely nothing was said about a search for an increase in performance. That was brought in to the picture by other postings.

I like, you sniper5, bought the ES for quality and comfort, not speed.

Given the world's situation and the rising costs of gas, it doesn't hurt to look for a little more change in the pocket and less money shelled out to the oil mongers.

In the long run about ruining the engine....I can't speak to that. The longest I have had a K&N was 60k miles in an SSEi before I traded it in for the ES. I can say that I did not see any effects that I would notice. No oil leaks, no air leaks, no drop in performance, no decrease in gas mileage.

However, if someone has a long term side by side comparison of the two filters (K&N and stock) in the same engine (doesn't have to be the 1MZ-FE), I would love to see the results. For now, I have to trust the data from K&N and my experience.

thanks for the input, though.


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i agree with both sides

it obviously does save gas with steviej's car

( but did not with the 3 i tried it with,also the cars were not new when the filters were installed one more variable)

and it will let more air in but at an added expense

not sure how much damage is done by dirt particles

especially when on that tiny level

i still say a good motor vac a year is one of the best gas savers and properly inflated tires

plus a good cold air intake with lower restriction exhaust

these are more performance minded ideas

but the first thing i reseach about before i do a performance mod is will it save me gas or cost me more

so far i have the cleanest running es 300 (emissions test) with the highest miles per tank of any es 300 from my lexus dealership, 94-96


i would be interested to see if the mileage on your car drops as the filter creates a bed of dirt

but there are still too many variables to take into account to get a preoper reading

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3 whole mpg is one helluva increase in milage from just a filter. I put a K & N into one of my cars and did not notice any substantial mpg differences, and only slight performance gain. I would say that K & N are most definately worth it though, just for the fact that they are reuseable. Some engines must benefit a lot more mpg-wise than others. I'm curious if there is anything unique about the design of the '02+ cars that make them better suited to K&N than most others. Is the stock filter really that restrictive? Thanks for the heads-up steviej.

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  • 9 years later...

Fast forward to 2012

2005 ES 330

Changed to K&N

Increased the mileage by about 2 mpg.

Measured the mileage before and after the filter change on same route, same traffic pattern, multiple times, counting the new regular filter in. Did not notice any difference in power/acceleration etc.

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