K&N Air Filters

Only the obvious one - less air filters to buy. Here is 2001 Prius with about 50k miles on a K&N. No obvious effects on power or mpg to report.

Over the last few engine oil analyses, there has been a subtle increase in silicon - perhaps you're already aware of the reputation (in some circles) of these filters letting dirt in?

I may not choose to run this filter indefinitely in Prius. If you do, it would be good to see some engine oil analyses.

 

IMO, I would not use one in the desert area of the western USA. Ex: Nevada, Utah, Arizona, etc. The sand that is in the air is really fine (small particle size). I don't think it's worth the expense of decrease engine life. Like I said, it's my opinion.

 

I actually bought one, but didn't put it in after hearing about the potential for more dirt.

Um, by the way, do you want to buy a K&N filter for a Prius? I happen to have one lying around.

 

<div class='quotetop'>QUOTE(Boulder Bum @ May 15 2007, 11:38 PM) [snapback]443007[/snapback]</div>

Well, what if you were in some area like Seattle, where it rains a lot? That it may actually be useful. You wouldn't really have to worry about dirt since the rain would keep it out of the air.

 

Just learned that K&N warrenty your engine for a million miles while using their filter, but the fine print requires you to use the "prefilter" they sell. It's a "sock" that fits over the main K&N filter. It takes care of the fine particles that get through the K&N main filter.

 

<div class='quotetop'>QUOTE(Boulder Bum @ May 15 2007, 08:38 PM) [snapback]443007[/snapback]</div>

I have been using K&N air filter since the 80's in all my vehicles and it does make a difference in throttle responds, also I have not had any engine problems. I also use Mobil one systhentic oil and changes it at every 5000 mile. I have one installed in my 07 Camry. I am looking to buy one, how much are you selling yours for?

Wayne

 

I have been using K&Ns "forever" with zero problems in extremely hard use scenarios with absolutely no problems. If "stuff" is getting in then most likely the cleaning of the filter has been too harsh (ie: using compressed air or hard water streams).

I think the performance (economy and/or power) would be minimal on the Prius but pennies add up to dollars and a properly maintained performance filter should not hurt the longevity of the engine.

 

I will no longer use anything but a dealer air cleaner on my new cars. It is not that I think they are better, but rather because of what the Infiniti dealer said after I paid $300 for diagnosis and replacement of the MAF sensor. They will not guarantee the new sensor at ALL if I use anything but THEIR air filter. They blamed the failure of the original sensor on the use of a Fram aftermarket equivalent. I know they are full of $hit, but they are in a position to make the claim and make it stick. Life is too short to take the time to fight them.

With a 150,000 mile warranty on the Prius, I won't risk the same BS from Toyota, and I'll just use their overpriced filters. I do save the coupons I get from the local dealer so I save a little.

 

The K&N filters require "oiling" and that has been shown to be a problem with sensors if too much oil has been used. You basically only want an extremely light mist of oil.. no more than that... Almost everyone I have ever met over oils their filters... One refill kit of oil will last me decades and I have never had a sensor or dirt issue.

 

<div class='quotetop'>QUOTE(tnthub @ May 16 2007, 03:14 PM) [snapback]443725[/snapback]</div>

Agreed. Lots of F-body guys had problems with their automatic trans because of this.

 

<div class='quotetop'>QUOTE(wayne60014 @ May 16 2007, 01:41 PM) [snapback]443601[/snapback]</div>

I have a K&N air filter for a 2007 Prius that sells for $39 shipped on autoanything.com and a recharge kit that sells for $20.

I'll sell them both for $45 shipped if you're interested.

 

<div class='quotetop'>QUOTE(Alexstarfire @ May 15 2007, 09:09 PM) [snapback]443035[/snapback]</div>

Rain? What's that? I think we may have had a couple of inches this year. There are small children in LA who have never seen the stuff!

I had K & Ns in my last three cars. The Eagle Talon Turbo was much improved in low speed drivability and throttle response. My two current Subarus, I've seen no benefit, driveability, power or mpg-wise. I was tempted to get one for the Prius, but probrbly won't, after hearing mostly negatives on Prius with K & Ns.

 

<div class='quotetop'>QUOTE(subarutoo @ May 17 2007, 03:23 PM) [snapback]444348[/snapback]</div>

Well, what I hate the most about hearing about these filters is the extreme lack of comparisons. I know the more air helps the fuel burn, etc, etc, yada yada but I'd like to see it compared to something. I have yet to see any charts on power output, response times, FE, or anything else for the matter. All I've ever heard about these filters has been nothing but words, and quite frankly I'm done trusting words. The numbers always speak for themselves and a lack of numbers doesn't look to good for me.

Don't get me wrong, it's not like I've actually gone to go look for numbers for the K&N filters, but I've never seen anyone say anything about numbers, and this is far from the first time I've heard about them.

Anyone have some numbers to look at?

 

I'll not try to encourage or discourage you re getting a K&N.

You save almost the cost of a filter every time you would have changed the stock Toyota filter if you get a K&N, as the K&N will last the life of the car. Do be careful to warn any service personnel that they are not to discard the air filter!

The K&N has to be washed - I have always done it in a sink - fill with nice warm water, gently immerse the filter and pull it out repeatedly. I use dish soap to get the (dirty) oil out. Then I gently rinse the filter. Once dry, I spray on the filter oil. There are sand bars in the sink when I'm done!

The 2001 Pathfinder I just traded in had noticably more power with the K&N, and mileage improved slightly. Sorry, no numbers, other than mileage went from about 15 l/100km to about 14 l/100 km. I suspect only engines that use a lot of air would really benefit from the high flow of a K&N. Or perhaps engines with air filters that are too small due to space considerations under the hood.

I've never had an engine wear out using a K&N, but I've never put really high mileage on a vehicle. I'm usually finished with my vehicles once they turn 100,000 km or so.

I don't think I'm going to bother to put a K&N on my new Prius.

 

<div class='quotetop'>QUOTE(Alexstarfire @ May 17 2007, 09:54 PM) [snapback]444659[/snapback]</div>

The general idea is that a brand new, high-quality paper filter flows well enough that the K&N may not be much better (all depends on the shape and sizes of the filters being compared and what your engine requires for CFM).

After some accumulated milage on the filters the K&N continues to flow better than the paper. The paper filter starts to clog and if you live in a moist climate you may end up with a wet filter which then starts to convert back to wood pulp and further dimishes air flow through it. This is assuming you have a proper sized filter for your car and application. There are cases in high performance cars that even a large K&N filter presents a resitriction. I've seen guys running 700rwhp supercharged Camaro's who change the size of their K&N and gain 30+rwhp.

 

K&N Filters *do* have a higher flow, but here's the kcker, it makes *NO difference* on the Prius because its tiny rev-limited 1.5L Atkinson-cycle engine simply does need much air.. My calculations suggest that even at max RPM, the engine air requirements don't even reach 300 CFM, which any old fibre filter is capable of supplying..

It's on large-displacement high-revving 6 or 8 cylinder engines that require absolutely massive amounts of air that high flow air filters can have benefits, but that's simply not the case on a small engine, especially a small engine that uses a shortened Atkinson intake cycle like the Prius has.. Therefore, on the Prius, the only reason to consider a K&N is to reduce filter replacement costs- it has NO power benefits at all..

 

So how can you tell whether you have a K&N filter in your car or not? The only writing I see along the filter is "Made in Japan."

 

Did you put a K&N on the car? If not it's probably a paper style. Look at the filter, if its dark red (oily), than its a lifetime.

I have always liked K&N, but have my doubts it would do anything to help milage or performance.