Has anyone here tried using a K&N air filter?

There's reverse flow out of a single intake valve, but I have a hard time believing it will cause a significant increase in fuel/air vapors making their way all the way out to the airbox. There will be another intake valve open with the cylinder on the intake stroke whenever there is out flow from another intake valve. That should be enough to keep the air/fuel mixture inside the intake manifold rather than allow any extra out to the airbox. It shouldn't be that different than an Otto-cycle engine, other than some increased turbulence inside the intake manifold.

 

Your friend needs to place a "Save a tree, pollute the air" bumper sticker on his car.

 

Avoid using the K&N air filter with your Prius. The oil could foul the mass air flow sensor and cause a number of problems.

 

I purchased and installed a K&N air filter on my 01 Prius back in 05. I ordered on ebay motors from a seller named Exotic Truck & Auto Gear for $27.95 Well, they're not coming up on ebay motors now, it may have something to do with "buyer beware" warnings posted on places like TitanTruck.com forum. Anyway, 2 other companies are selling them on ebay motors for $44-48. Also available on Amazon.com for 44. A local store has it for $41, no shipping. I too want to know others advice and experiences with the K&N air filter. As for mpg, I've averaged 45 in the summer, 40 in the winter, upper 30's in COLD weather (haven't done the grill cover or block heater). I've had issues the last couple of years with warning indicators including the main warning, erratic engine performance and the engine shutting off after starting it on a cold day or hot Texas day, but that could be various things causing that. Recently, I rcvd a letter from Toyota indicating some error codes and if I've experienced any of them to take it to a dealer and they would service it under warranty. I did have error codes P3191/P3102, took it to the dealer and they cleaned the throttle body (follow TSB 0180-09). Bingo! It runs like new! I say all this to say perhaps the oil from the K&N eventually enters the throttle body and gunks it up. Perhaps I did apply too much oil, or didn't allow the excess oil to drain off completely. I won't rule out the possibilities, but I'm sure I allowed plenty of time for the oil to penetrate the fibers as instructed and I don't do shoddy or sloppy work. Finally, I would say the benefits of the K&N out weigh any potential problems, as long as we're careful to not apply excessive oil and have the throttle body cleaned if the above problems arise.

 

The Prius air filter can be serviced and (cleaned and oiled) just like the K&N filters.
Dave Weaver (2001 & 2004 Prius owner)

 

Um, OK, how is that oiled paper air filter working out for you?

 

Once a year or so I clean the MAF in the intake by spraying with MAF cleaner. I clean the throttle body while I'm there. No more related codes. One K&N air filter installed in 2005 instead of about 5 paper filters.

 

FWIW, I tried a K&N on my 06 prius...the increased noise sounded cool for about 5 seconds then got VERY annoying......

And to boot, it make my car die out in the middle of the road. I switched right back to the OEM filter....

 

over-oiling is usually root cause of all K&N filter problems. I was told to oil it only on air side (not on TB side).

 

I have a drop in k&n filter, I've had it for 20 thousand miles without issue. like you said spray the oil on the air side, and use it sparingly, there is no need to use a lot of oil on the filter.

 

On one of the automotive sights I frequent, there's usually a newbie popping up asking about the K&N air filter and time and time again they are told not to use it because of the MAF sensor becoming contaminated. On another site, the factory engineers have come on telling what they have to go through in designing an air intake system and explain why a K&N air filter is not only not recommended, but why nothing is accomplished by using one. I'll use their advise and stay with a paper filter.

p.s. The recommended air filter change for my previous car was at 60,000 miles.

 

When I first got the PRIUS, I thought the gas engine was so loud. When I went to change the air filter, I noticed that the previous owner had a K&N. I put in a new stock filter and now i'm happy. The stock filter is fairly cheap, I wouldn't go with the K&N -- just too noisy in my opinion.

 

I like the K&N filter because it can be reused. The pruis really doens't benefit much from the K&N other than that.

 

I have a K&N air filter sitting in a box in the garage. I inherited it when I bought the Prius from it's first owner and it severely needed cleaning/re oiling.

I looked around at prices for the oil and it was cheaper to get a paper filter.

 

Yeah the K&N helps out a lot in terms of mountain passes. I would guess it adds a few hp.

Also disconnecting the tuned air intake tube helps with more mid range power at the expense of noise.

DROIDX ?

 

over 200,000 miles between our 2 Prii ('04 w/ 108,000 and '05 w/ 98,000): no issues with either K&N air filters. still getting 47MPG average. don't overoil, don't waste paper filters. YMMV.