K&n Air Filter

[kgjzj]

I just purchased a "mint" condition 99 LX 470 from the Lexus dealer. The vehicle has only 80K and is in showroom condition. I'm amazed at the vehicle's condition. It's flawless!! You literally could not believe it is a 99 model. Anyhow, my wife and I love it, but I was wondering if anyone has added a aftermarket K&N air-flow system to replace the stock airbox system and if so, is there any improvement in performance that is worth the cost of the K&N system. Love the site...very informative!

[Krazy Lexus Owner]

I just purchased a "mint" condition 99 LX 470 from the Lexus dealer. The vehicle has only 80K and is in showroom condition. I'm amazed at the vehicle's condition. It's flawless!! You literally could not believe it is a 99 model. Anyhow, my wife and I love it, but I was wondering if anyone has added a aftermarket K&N air-flow system to replace the stock airbox system and if so, is there any improvement in performance that is worth the cost of the K&N system. Love the site...very informative!

I have always replaced all my OEM's air filters with K&N filters for two reasons:

1. Better air flow with less air intake constraints which equals more horsepower.

2. Washable which saves you $$$ down the road.

[mburnickas]

more HP is not gonna happen unless you race (aka high PRM's)..Fact here and we drive a lexes here not a vette.

#2 is, for me they are not worth the time and effort. You WILL have problems done the road either with failing sensors due to over-oiling (had happen) or increased engine wear from under-oiling (as shown in oil tesing- had happen).

Either use OEM or Amsoil new EAA air filter. Best bang for the $$$ is Amsoil and no failing sensors and no engine wear increasings.

[Jim_Chow]

I've heard stories of K&N's leaking dust into the engines, also that there's no noticeable improvement in air flow. I only use OEM filters. I've only used OEM filters on my 86 4runners...21 years and 205K mi later, no issues. On the 3rd gen 4runners and taco's, the air mass sensor changed to a wire-type. The oiled filters would gum them up, causing the vehicle to do weird stuff like stall on freeway onramps, etc. Do it at your own risk. FWIW, Toyota has gone from the cyclonic air filter on the Australian turbo diesel LC79's to the rectangular type found on the current LC/LX for the new 4.5L twin turbo diesel, so they must have confidence in the rectangular OEM filter. Besides, OEM filters aren't expensive...only $22 for OEM toyota landcruiser filters on discount. It's just like the premium vs. regular gas argument. If you aren't willing to spend the few extra bucks for premium, you shouldn't be driving a car that recommends premium. Ditto w/ OEM air filters.

[Texasoil]

Toyota has thoroughly tested the OEM filter assembly in al kinds of conditions. It IS the best overall for the vehicle. Lots of hard technical research was done by the Q45 tuners (some of those guys really run those hard) comparing stock vs K&N pop charger cone filter. The stock set-up feeds cool ram air from a the highest pressure area in front of the radiator, while the K&N set-up uses under hood (hot) air from a significantly lower air pressure region. :cries:

At the throttle butterfly, the stock air filter flowed MORE #/hr of air than the K&N in all conditions.

Stock filter also removed more very small dust particles than K&N (both kept gravel and big dirt particles out, but the small stuff is what eats up engines.) Folks who had K&N filters were losing mass flow sensors due to erosion of the hot wire. :chairshot:

Recommendation is to stay stock unless you ford deep streams in which case you want a snorkel in any case to avoid water ingestion