K&N Air Filters

The end point of that argument is "remove the air filter entirely". The problem with that should be obvious.

I trust that the design engineers knew what they were doing, and so I will use Toyota filters.

 

<div class='quotetop'>QUOTE(mattleb @ May 30 2006, 12:13 PM) [snapback]262748[/snapback]</div>

I had an open filter "K&N knockoff" filter on my previous car, which is advertised to add 5-10hp (!). I would suspect it to be more like 1-2hp (if even that), which is imperceptible. I never had the car dyno'ed with and without to confirm, as I really didn't care.

The difference is the sound - without the plastic box muffling the sound (on the Integra, anyway), you will hear more of a growl when you stomp the gas. The other nice thing is that it is washable, so it saves some money on replacing filters.

It lasted me about 6 years and would have gone longer, but the rubber seals holding the "polished tube" to the intake started to dry out and crack, so I ordered another kit from eBay for $50.

Overall, a worthy investment to save a few bucks, and give your car a little growl, just don't buy it thinking it will knock you down with increased power. :mellow:

Not sure how it would work in a Prius though... I wouldn't try it until my warranty is up, and likely not at all considering the working of the HSD (ICE constant on/off, etc...)

But that's just me.

- Kevin

 

i had a k&n in my firebird. it may have made a difference, but i didn't notice. when they are advertised as 5-10hp more, that is in the most extreme cases. in a prius, you'd be lucky to get 1hp.

also k&n filters are easy to over-oil, or under-oil. over-oiling causes the oil to co with the air and enter the engine. that can cause problems with the emission systems, which can have a bigger loss on hp that you would
gain from the filter, sometimes worse (break the maf sensor). under-oiling causes the filter to not trap enough dirt.

my final opinion:
with the price of a k&n (yes you can wash it, but the recharge kit costs too), the very little it would help in a prius, and the chance of oiling it wrong, it's just not worth it.

 

I have used K&N filters on my Tundra, Camrey & Harley's. After over 100k miles I like them.Approx 1.2 to 2mpg better in the Tundra over 30K miles. Not much difference in the Camrey and its the filter Harley supplys with the stage one kit. They are easy to clean and re-oil . Will I get one for the Prius yes if I can find one.

 

I've done the k & n air filters in both our '04 & '05 Prii. Use the attached word doc to make it work. part # 33-2186. B)

Cheers,

Curt.

 

As I've posted before, for larger engines that need plenty of air, and where a stock airbox and filter may be the cause of intake restriction, a high-flow filter like a K&N may actually make some difference..

For the Prius however, because of its Atkinson cycle and rev-limited design, even at wide-open-throttle, the engine's air requirements are miniscule (ie sub-300 CFM) and a standard filter has no problem passing this amount of air; a K&N makes *ZERO* difference to engine power on a Prius.

That said, I do have a K&N on my Prius, but only during the winter months when the air particulate count is low, but moisture content is high (a situation where the high flow oiled media excels), but once the weather warms up, I switch back to a Toyota filter for the dusty summer air.

 

I bought K&N air filter for 2001 Prius specifically to avoid the throwaways. There has been no perceptible improvement in mpg or power in 50k miles.

The problems most commonly discussed are its oil dripping on the MAF sensor, and the potential for letting dirt get into the engine.

On the oil drip, this is a clear risk with the classic Prius. When I cleaned and re-oiled mine, I drained it on paper towels before reinstalling. No MAF problems so far. I expect less risk in the new model Prius because the air filter is not directly over the MAF (not that it couldn't happen...)

On the dirt ingestion, I have had several engine oil analyses and the silicon is not elevated. But see also:

http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm

for standardized testing results.

 

<div class='quotetop'>QUOTE(finman @ Jun 1 2006, 09:34 AM) [snapback]263977[/snapback]</div>

Do you get a gasket with a new OEM filter, or if you decide to quit using the K&N do you need to buy another gasket?

 

See here:

http://www.vfaq.net/mods/AirFilter.html

The OEM filters have gasket which is cannabalized for K&N filter install.

 

So I just bought and installed a K&N engine air filter. I had been frustrated with my Prius relatively declining mpg.

Two things:

1. There was an additional gasket with an adhesive. What was that for?

2. How long should I give it a try before I realize everyone on the Internetz & Youtube were right about K&N on Prius-es?

 

First time you calculate your fuel efficiency ought to do it.

The GOOD news is that your 04 is already 3/4 through its service life, and you're probably not going to hurt the car that much with the new filter. If you keep it long enough to ....ah...."clean it" be VERY careful with the oil, lest you DO foul up your MAFS.

The OTHER good news is that if you FOD out your intake, then taking it apart to clean it might just correct a problem that was contributing to the poor fuel economy that caused you to buy the K$N filter to begin with....

Good Luck!

 

About a year. Everybody in the Northern hemisphere is about to see their MPG rise due to seasonal warming. Keep records of your previous numbers, the best proof is likely going to be year-over-year monthly averages.

For my money, the K&N is exactly the right accessory to put on a carbureted dirt bike. It really will achieve better performance than other types of air cleaners throughout the duration of a typical race. It doesn't matter if you get a little extra dirt in when you plan to replace the engine as frequently as a race team.

I don't think they have any place on ordinary family cars- but I know they have also been used there without causing harm.

The whole trick is to prevent over-oiling of the element- it can lead to fouling the MAF. You generally want to use a crazy-tiny amount of oil + some time to work it around.

 

My take is No.

They advertise it has "more breathable" you can see light when you look through it vs the paper filter. That just means more dirt will pass through the filter.

Having it oiled incorrectly can damage MAF sensor

On paper, yes it does make more HP. In real word? its probably unnoticeable .

 

Right after installing the K&N filter, I noticed a significant difference when I press the pedal-- I definitely get better acceleration than the usual slow rev.

 

I'm willing to venture that it is nothing more than the placebo effect.

 

This is why they don't use derrieres to measure things like 0-60 acceleration.

OTOH if your paper filter were significantly clogged, then yeah.....even an oily cotton....a $50 oily cotton rag might improve your engine's performance.

^This.

Of all of the reasons to buy a permanent filter this would seem to be the most rational, and there's no denying that during the normal life cycle of a car that you can save five or six disposable air filters from going into a landfill.
With proper maintenance and maybe an additional throttle body teardown for cleaning.....I'm guessing that there will also be no major injury to the car by using one of these filters.

As Always

YMMV

 

I wonder if they’re often changed to soon. Depends on environment too, driving dirt roads for example.

Here on the wet coast I changed our engine and cabin air filters, for the first time, around 88K kms (roughly 55K miles?), and I’m not sure why. Especially the engine air filter, still looked near-new. I’ve read that nowadays, with computerized fuel injection, an older air filter actually improves mpg, by slightly reducing air capacity.

 

I slapped in the engine and cabin k&n air filter when I first got my prius.

Never had a problem.

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