Expensive air filters

<div class='quotetop'>QUOTE(Tideland Prius @ Oct 22 2007, 10:52 PM) [snapback]529125[/snapback]</div>

I thought that was a massage but if you could not tell it wasn't you who got it

Gabe

 

<div class='quotetop'>QUOTE(subarutoo @ Sep 11 2006, 03:20 PM) [snapback]317878[/snapback]</div>

Argh. K & N filters are made for racing engines, and for people who want to think they have racing engines.

They will pass much more dirt than a conventional air filter, because racing engines typically get rebuilt after each race. They are actually at their most efficient (for catching dirt) after some dirt has collected on the filter, and increased the effective surface area of the filter.

They are also good at skewing MAF sensors, and eventually knocking them out altogether. Ironically, Toyota's parts boutiques carry them, as they are popular with the off-road crowd, and when they sell a K & N filter that knocks out the MAF sensor - well, Toyota has to pay.

When the filter was purchased elsewhere, the customer pays. MAF sensors are not cheap.

 

<div class='quotetop'>QUOTE(jk450 @ Oct 25 2007, 03:40 PM) [snapback]530474[/snapback]</div>

A lot of people claim their vehicles have quicker acceleration, more power, better fuel economy, and better throttle response after they installed a K&N air filter. Personally, the only thing I ever noted (many years ago when I was dumb enough to buy into the hype) was more noise through the intake, which some weak-minded individuals susceptible to the power of suggestion might perceive as increased performance.

 

<div class='quotetop'>QUOTE(Tideland Prius @ Oct 22 2007, 10:52 PM) [snapback]529125[/snapback]</div>

Honest shops refer to those types of services, somewhat disparagingly, as "wallet flushing."


<div class='quotetop'>QUOTE(priusenvy @ Oct 25 2007, 08:29 PM) [snapback]530508[/snapback]</div>

I noticed something else, starting many years ago. I noticed lots of folks coming in to get "check engine" lights and performance problems diagnosed. The problem is often traced to oil contamination of the mass air flow sensor. Oil from the K & N filter.

If the vehicle is faster with a K & N filter, then it wasn't getting enough air, even at part load, with the stock filter. You can watch the MAF (in grams per second), as well as fuel trims (in percentage), on a scanner and see that there is no change.

Racing filters are for people who have racing engines, and people who want to have racing engines. They typically filter out less dirt, because racing engines are normally rebuilt after every race.

Irony: Toyota sells K & N filters in some of their TRD parts boutiques. If you buy the filter from them, and the filter kills your MAF sensor, AND Toyota diagnoses it, they have to pony up. If you bought your filter somewhere else, and Toyota diagnoses the same problem, you pay.

 

<div class='quotetop'>QUOTE(priusenvy @ Oct 25 2007, 05:29 PM) [snapback]530508[/snapback]</div>

I have used K&N air filters for years. The only difference I noticed was increased power at freeway speeds. No increased fuel economy. When they are dirty they filter better than a regular air filter. But cleaning and re-oiling can be a pain and if over oiled, you can clog a MAF and void your vehicle warranty. I probably wouldn't use them during the warranty period.

 

I wouldn't use anything but a paper filter. Car manufacturers seem to have a similar opinion. If I use a genuine filter each 12 months which would be over kill, and that filter cost $50 then that engine protection would cost me just under $4.20 a month. A lot of people would spend that on coffee in a day.