K&N Air Filters for 2008 Prius

I used to use K&N filters on my race cars. Very minor improvements in HP, worth it in a race car.
I've also read that they aren't as good at catching fine dust as a good paper filter. Not a big deal on a race car, but if you want to run your engine 200,000 miles you might think twice.
Since the Prius engine seems to already have a pretty large air filter for the amount of air it moves, I wouldn't expect much difference with a K&N.

YMMV.

 

If the oil used to coat the air filter element gets into the mass air flow sensor, this will cause problems. This may be a problem with Classic more than 2G since with the older model, the air filter element is over the throttle body.

My maintenance approach is to replace the Toyota air filter at 15K mile intervals.

 

They just don't filter as well as a paper filter.

 

I still use the K&N on my 425+ hp show car, but the Prius?
Sure, I thought about it as a knee jerk reaction, but then I really thought...
"Since the engine isn't ON that much and has a very limited HP potential why do I need to screw around with the air flow, can't the computer figure this all out?"
Needless to say, I have a K&N and a racing MAF sensor on my 99 Silverado.

(Hint?: I think it's money down the rat hole with nothing to show for it)

ZC1

 

I put one in the wife's VW 1.8Turbo Beetle. I am unable to notice much of a difference in Horsepower if any, but maybe a slight and I do mean slight bump in fuel economy. The only reason I decided to put it in there in the first place is because she had 2 paper ones in a row from 2 different manufacturers flatten out on her and I wanted one that had a more durable build quality. By the way according to K&N's website is that if you provide proof that their filter kills your MAF they will pay for it.
K&N Consumer Protection Pledge

 

a plus for K & N (and others this type) is if you hit water they stop it better than paper

 

If it really made that much of a difference why would Toyota use paper? (and don't say because it's cheaper, this car is sold on MPG, if Toyota could get it higher they would)

 

I installed K&N on my CX-9 for 3000 miles so far after the original 1000 miles on OE filter.
My feeling is
- no improvement on MPG (significant enough to draw any conclusion plus or minus)
- engine is more willing to rev (quicker response - less hesitation)

If one changes old filter to a new one, one will always see improvement on MPG.
When people see MPG gain from switching to K&N, I need to question if the comparison is scientific at all. What if one uses a new paper filer instead? One also could see gain in MPG
if the old one was really dirty.

Why doesn't Toyota use K&N?
Because it is more expensive by $30-$40 each, and YOU pay for the maintenance not Toyota.

K&N filtration capability is close to paper or even on par but not exceeding OE filter. I believe Toyota is already using good paper filter (has price tag to match also $10-$20 each). So, K&N filtration rating is most likely lower than OE ones, but not by much to cause any concerns.

Anyway, don't buy K&N for better MPG. K&N does not even claim better MPG themselves.
According to K&N, there is no hard evidence that any customers ever established to prove that the oil in K&N filters caused MAF failure from their original products. If so, they will pay for the repair.
However, re-oiling by customers themselves after 50K miles is a big concern, since some customers might put too much oil on them. According to K&N, they put the oil on MAF, and they could not reproduce the claimed MAF failure themselves. Read the K&N website for more details.

At least, we should read stories from both sides to establish our own opinions, not based on hearsay.

Personally, I will probably put my OE filter back for another 3000 miles to get an even more objective comparison myself.

 

if the oil goes thru the filter there was to much