K & n oil filters

It has been debated on several other threads. There are two principal disadvantages with K&N filters for the Prius:

1) They let in more dirt.

2) It is fairly easy to get oil on the mass flow sensor.

I wouldn't use one.

Tom

 

Hold one up to the light, you can see the holes in it. The fact that they pass more dirt than a paper element has been well documented, not that it needed to be.

If K&Ns were any good you would see them as standard equipment on multi k$ expensive commercial and military off road equipment. you won't because those people know better.

 

That's FUD and BS. I've been using a K&N air filter for the last 4 vehicles:
old Jeep CJ5, 10 years over 160,000 miles;
newer Nissan Pathfinder, 70,000 miles;
and currently 2 Prii (his and hers!)...2004 and 2005, both with 85,000 miles. EVERY vehicle has had no problems with air intake, mass airflow sensors, or "letting in more dirt". my 2 cents, your mileage may vary. And none of these vehicles have I had to throw away a filter. wash and re-oil.

 

The issue with MAF sensor fouling is possible with Classic Prius, where the air filter is immediately above the area where the MAF sensor is located. I've seen a few posters who have reported that specific issue.

I would say this problem is less likely with 2G, since the air filter is located to the side.

However, the idea of an oil-soaked air filter goes back to the 1950's, and I personally do not see the value of such an idea, having to remove and clean the filter periodically, etc. I don't mind paying $13 for the correct air filter and replacing it after it collects sufficient dirt.

 

I think they might be a good filter for an 30 year old car that needs to breath as much as possable to get the extra hp. I think it would be a waste and i'm willing to bet Toyota would not warranty a ICE repair if they saw a K&N filter in the car, Such as excissive oil consumption, or anything of that nature.

 

This is an excellent point. One of the main reasons for using a K&N filter is to improve breathing for more power. This makes sense for racers and heavy equipment, but not for a Prius in ordinary use. Prius engines are lightly used; ultimate horsepower is seldom an issue.

Tom

 

Hi Tom, you won't see them on well maintained heavy equipment either. Those engines can cost many times the price of a Prius engine and are expected to last several times as long as a Prius engine. The owners want the best filtration they can get.

There is also usually more restriction in the airbox and intake ducting than there is in the air cleaner element so drop in replacement K&N elements usually don't show enough gain to be reliably measured on a dyno.

 

Yep i work for a highway construction company, we would never use K&N in our equipment. Not when it costs, 20-75k to rebuild a motor.

 

I assume you mean the cone CAI's and not the drop in's?

I tried installing a cone CAI filter on my 07 when I first bought it as I had 2 left over from other cars. I got one installed real good and the car ran really really bad. It would just bog if you gave it the gas. If you very slowly accelerated it would be ok though. I assume the maf sensor did not like it. Really big difference in the way the engine felt with a cone on it and not in a good way.
You could hear it too inside the cabin. That little 4 banger sucks some really good air!

It didn't throw a cel though.

 

I believe this is the reason for turbocharging, force more air in for more power, assuming the fuel injection/cylinder head is up to it. But the AF doesn't do that, it sits and does nothing. It isn't the most restrictive element in the system, it isn't a race car. I have never floored my Prius in the three+ years had it. There are plenty of engines out there running no AF at all. and have "no problems." The question is what is better, right? Might search specialist sites like bitog for consensus on K&N. I like the three layer Toyota Denso filter. Seems a safe bet to me. to all.

 

DBG,

I put in a K&N air filter (drop in replacement style, not a CAI) in my '06 at around 60K and I turned 200K last night. I have a K&N on my hot rod too and have never had any issues related to dirt passing thru easier than a paper filter. No noticeable change in power or fuel economy with it. And I've floored my Prius' gas pedal many, many, many times BTW!! It only red lines at 5000 rpm and no ill effects noted so far. So pick your poison and keep up with the intervals to change/clean whatever you have and it'll be ok!!

Joe