K&N air filter now available for latest generation Prius

<div class='quotetop'>QUOTE(Boxster...WRX...Prius? @ Nov 10 2006, 04:05 PM) [snapback]347205[/snapback]</div>

Don't do it! K$N's are not good at filtering and will let 50% more dirt into your engine than the factory filter. They also plug in 1/3 the time it takes a factory filter to plug. Toyota has posted many TSB's on oil saturated air filters on their other vehicles and will be quick to void your warranty, especially if the MAF gets taken out.

Plus the K$N will not gain you any power at all.

K$N=JUNK they have great marketing skills though. If you want to know more search under ISO and K&N. There was a scientific test done to bring the facts to light.

 

K&N is a popular subject on BMW forums.
Most people think it does gain some horsepower thru better breathing during high revving.
However, the re-oiling of the filter is a catch. Over-oiling would cause some oil get sucked into
air intake. Under-oiling would cause improper filtering. Therefore, there is certain long-term effect
to be observed.

If you do swicth to K&N, please post your finding for us. Thanks.

 

I did the same as Efusco. Can't say I really had felt any difference at all. But i just bought it because I was hitting 15k in mileage. Snip snip, and it fits.

 

I got this same notification email from K&N today also. I am thinking about finding one if its a reasonable price. I had one in my previous Yukon and 4Runner and they might not have improved the mileage much but its nice buying only one filter for life. But you do have to be careful with the oiling and not over do it.

 

Here's the link to the K & N article:

http://www.knfilters.com/search/product.aspx?Prod=33-2329

I've used them for years on 3 different vehicles. It did definitely improve the low-mid range pick-up on my '90 Eagle Talon Turbo. I didn't see much change in the two Subarus that I currently have. I drive over 25,000 miles a year, so I'm thinking of it as a cost savings over the OEM Toyota filters. I don't expect any performance gain with the Prius, though.

 

I have used the K&N in a 2001 Prius for long enough to have cleaned and re-oiled it once already. Due to the risk of oil drips onto the MAF I left it on paper towels overmight before reinstalling.

No noticed change in fuel economy nor power; this engine is simply not a heavy breather. The concerns about dust ingestion are apparently well-founded and I encourage folks to consider doing used engine oil analyses as well. If there is silicon or wear metals, you will know about it. Thus far it has not been a problem for me.

 

I was also thrilled that they have released the filter I already have mine on order through the local speed shop and it should be here on Friday.

These filters do have better air flow than standard air filters but the biggest gain when using the replacement high flow air filters is that last a long time and save you money because of their longevity. They do remove some of the 'bogging' when accelerating heavily but that gain is lost when a vehicle uses a Constantly Variable Transmission.

If you want to really increase horsepower and mileage on a conventional gas powered vehicle you would want to look at the various systems which increase the size of the filter and remove housings that restrict air flow.

The Next step after that is to replace the Mass Air Flow meter with a more sensitive unit. Then remove exhaust restrictions. Then update vehicle air flow dynamics on the exterior of your vehicle. Or just buy a Prius and get the best of all worlds!

The big trick with all of the permanent air filters is in the cleaning and re-oiling. (Currently I use three different brands in my vehicles. K & N, MK, and Edelbrock.) I have used high flow filters on multiple vehicles for over a million miles. Here is the method of cleaning that works best:

Do all of the cleaning and oiling inside to prevent contamination of the filter.

1. Always follow a three month/6000 mile cleaning schedule.
2. Clean the filter with the cleaning solution recommended by the manufacturer.
3. Use a bucket of water to rinse the cleaning solution off of the filter.
4. Let the filter dry completely. Never use compressed air on the filter, you can actually block the filter with grit by using compressed air.
5. Use the manufacturer's recommended oil.
6. Spray the oil on while holding the sprayer 12 to 15 inches from the filter.
7. Spray once and then walk away from the filter. Come back 30 minutes layer to see if you have good coverage. Remember that oil spreads slowly and if it is cold out it will slow that spread time.
8. When the filter has good coverage then wipe it down with clean rags or paper towels to remove excess oil.
9. Reinstall the filter and drive on!

Just an example of what results I have seen when using these free flow filters:

When I installed the MK free flow kit on my Ford Ranger with the four banger I went from 22 to 26 MPG with my 37 mile daily commute. I also lost all bogs when climbing hills, passing, or pulling loads. The kit replaces everything from the MAF on with a conical permanent air filter that has about three times the surface area of the stock filter. When I replaced the MAF and the computer chip my mileage moved up to the current 29 MPG. The biggest gain was power from all of these changes. I can pull a load of sand in my trailer at speed on the freeway without straining the engine. VERY NICE for a four cylinder 2.3 engine!

On my wife's Subaru Forester I installed the replacement for the OEM filter and have seen the average go from 23.1 to 24.6 MPG. (Based on a years worth of tracking mileage.) The car does have better passing power and seems to have more consistent power and mileage even in the cold months.

The big thing to remember is that if you put one of the filters in your Prius you have just added items and time to your maintenance schedule. If you don't want to deal with cleaning and re-oiling the filter, I highly recommend that you buy the stock filter.

 

<div class='quotetop'>QUOTE(subarutoo @ Nov 11 2006, 02:28 AM) [snapback]347360[/snapback]</div>

You may want to check the Subaru's to see if they have the secondary air filter at the back of the engine. I know that the Forester has one and this filter is not normally listed when you look for air filters for these vehicles. If you have one the simplest method of finding the replacement is pulling the part number of the current (probably plugged) secondary air filter. To find the filter stand directly in front of the vehicle and it will be at the back of the engine compartment with clips holding the housing shut. (the main filter is on the engine sidewall.)

My wife had been having the dealer do the maintenance on her Forester. I noticed that the performance was going down and the engine kept heating up. Then I discovered this second air filter. It was completely blocked. I replaced it and the problems went away.

The dealer told us that the filter was not in the "Maintenance Schedule". I now do all of the maintenance on her car......

 

<div class='quotetop'>QUOTE(wile-e @ Nov 11 2006, 10:58 AM) [snapback]347499[/snapback]</div>

Our cars are '96 Outback and 2000 Impreza RS. I don't think either one has another filter. Never seen it anyway. Thanks tho.

 

Again, you can't compare the benefits that you get from a large displacement high horsepower engine to the Prius engine.. The Prius uses a 1.5L 4 cylinder engine rev-limited to 5000 RPM, but its actual displacement is even less than 1.5L because of its Atkinson/Miller cycle- by closing the intake valve late, the actual amount of air used is much less, and the electronic throttle just about never gets to wide-open condition anyways.. My calculations have shown that the Prius engine never needs more than 250 CFM air flow, which any stock air box and filter can provide. There will be no improvements (not small, not imperceptible, but absolutely *ZERO* improvement) to engine power and performance by adding the K&N to a Prius..

The only reason for using one is that it is cleanable and reusable (but watch out that you don't over oil, as that will definitely kill your air flow sensor, and immediately wipe out all lifetime savings from filter reuse).

As I've said many times, I use mine only during the wet seasons of the year when air particulate counts are low so I don't worry as much about dirt getting through, and because the oiled media handles moisture far better than fibre media (which may swell and clog). As soon as the roads dry up, I put on a regular Toyota filter.

 

are you people stupid? A k&n is way better than the pos filter that comes in any car, much less a prius.

 

nuh-uh!

See how these statements don't have any impact if you don't back up your opinion with some reasoning?

 

<div class='quotetop'>QUOTE(slow95gt @ Nov 15 2006, 08:21 PM) [snapback]349878[/snapback]</div>

Hey, are you saying that a Prius isn't as good as "any car?"

Please elaborate. Regarding the K&N filter, what do you mean when you say it's "better?"

I think we're in the process of exploring the pros and cons of the K&N product; some thoughtful input has been provided regarding its maintenance, cost, potential problems and the overall cost savings over the life of the car.

I'm not sure why you'd think that's stupid.

 

Peter c says that they arent any good, im saying they are the single best air filter you can buy for ANY car!!! All you have to do is wash em out and get a can of filter oil and spray it on lightly, it shouldnt be dripping off, and put it on the car!! I know this as im the owner of 2 k&n filters, one on a low 13sec 5.0 stang and the other being on a 8.5k rpm gs-r integra.

 

<div class='quotetop'>QUOTE(slow95gt @ Nov 15 2006, 09:06 PM) [snapback]349896[/snapback]</div>

While the gauze (K&N) and foam filters are serviceable and some MAY flow more, pleated paper out-filters either type, and by a wide margin. Guess how it is that foam and gauze filters (sometimes) have greater flow rates even though they're the same size and form-factor as the pleated-paper element they replaced?

If you guessed, "Because foam & gauze filter media have larger pores," then you get a cigar. And if you further reckon that, "Larger pores allow more crud to get through," then you get an extra cigar... but don't inhale or you'll never make President.

I'm still waiting for someone to claim better gas mileage from a K&N.

Someone said the oil in the K&N will repel water. I've not seen this to be true. Water runs right through gauze and foam filters. How? Because the water doesn't have to go through the oil, it goes through the PORES (tiny holes in the filter). I've run them on race motorcycles before when I wanted at least SOME filtration, and top-end wear wasn't as important because the bike was torn down regularly for rebuilds. My experience has been that water runs right through both foam and gauze filter media.

The difference is, water will make pleated-paper filter media clog almost completely as the water makes the paper swell and closes the pores, while gauze/foam units will allow the engine to continue running. Not that this is a good thing, considering that the water just dragged half the filter's captured dirt right on through with it.

GeronimoPFudgemuffin

 

I never claimed that the filter would prevent water from going through, but rather that the media itself would not be affected by water.. As you say, paper media clogs immediately and completely when it gets wet, and the oiled gauze will let it through- I completely agree with you on both these points..

As for dirt getting carried through by water droplets, unless that water also contained surfactant agents that could dissolve the oil film and/or you hadn't cleaned and re-oiled the filter for a long time and there was loose dirt on the surface of the filter, I don't think much dirt if any will go through due to a bit of water.. Think about it- dirt stuck to the oil will remain stuck while the water simply flows past, just like your hands after overhauling an engine- oily, covered with dirt, but nothing comes off until you apply soap.. Perhaps if you drove through a lake and it inhaled a bunch of water, but then you've got other problems to worry about..

 

<div class='quotetop'>QUOTE(slow95gt @ Nov 15 2006, 09:06 PM) [snapback]349896[/snapback]</div>

Again, best for whom, and for what?

Your cars are clearly performance oriented, and you probably enjoy working on them, so for you the K&N may be best.

For my Prius in particular, I've decided that I want to mess around with it as little as possible...and if that means that I can just have my mechanic replace the paper filter, not have to worry about cleaning/oiling an aftermarket filter, not face the potential hassle with Toyota if the MAF sensor goes out under warranty (or there are other issues in the area of the intake tract) etc., than that's what's *best* for me.

I don't want or need 1/2 or 1 extra hp that badly. And if there's no power gain, and no real cost savings, then what is the reason to change? I've gotten 200,000 miles of my lowly RAV4 using only stock paper filters, and compression is still good...I'd be happy with 200k or more from the mill in my Prius.

I did want better handling, though, so that's why I added the TRD suspension...that, to me, is a more worthwhile trade-off. Lots more expensive than an air filter, but with measurable improvements.

 

<div class='quotetop'>QUOTE(slow95gt @ Nov 15 2006, 09:06 PM) [snapback]349896[/snapback]</div>

Not the best for an Audi A6 at least. I drove one for 5 years and on the Audi World board there were a bunch of people that killed their MAF (mass air flow) sensors with the oil bleeding off of a newly installed K&N. Bad for emissions, bad for mileage, and bad for power. Now that and other Audi's of that vintage were known for MAF's that died easily from contamination.

That may not be a problem for the Prius. The Yahoo! Prius_Technical_Stuff group reports lots of cases of oil in the intake manifold, perhaps from oil overfilling, perhaps not. Though you may get a CEL from an oil overfill, I have not seen reports of killed MAF's.

Even so, I am very leery of putting one of those things on my car when the benefit is little to none.

- Tom