I just replaced all the air filters in my cars with K&N drop ins.
Gas mileage has improved between 10-20%

Dealer mentioned they've had some check engine lights come on, has anyone experienced this?

Also while searching the forum on the topic I cam across mention of the ECU being able to learn when the intake is changed. Is this a dealer option or user option?

Thanks for any responses

 

No never had any issues with any of my cars with k&n's. I've probably had at least 6 different ones on that many cars to.

 

Had mine on for 5000 miles with no issues. Like accelerate, I've had them on many vehicles with no issues (knock-wood). However, you will see people jump on here and say that it *could* potentially mess up the MAF, but that's only if you add too much oil to the filter.

I believe that what you are referring to is the ability for the ECU to "learn" and adapt it's settings based on your driving habits, air/fuel mixutre, etc, which is not really an "option" at all, but instead the way that the car operates.

Some will say that if you disconnect the battery, that you can reset it's settings to a new driving style. While that may provide an immediate effect, I also believe that the ECU is constantly adapting itself for your driving habits.

 

I'd say the gains you see in gas mileage can be attributed to the hot weather we are having in the NE and not the drop in filter.

 

10-20% gas mileage improvement seems a little high for just a drop in filter. What was your mpg before, and after the K&N filter?

 

these previous replies regarding te mpg increase are most likely correct. i have never heard of a car getting even 10% increase in mpg from a filter let alone 10-20% increase. you are either driving significantly more conservative, the warmer weather is helping, or your calculations are way off. if you reported hard evidence for even a 5% increase in mpg i would congratulate you

 

This was a nice response and yes, over-oiling will reduce the life of a MAF. I have placed a K & N in basically every car I have ever owned (on number 10 now). I love the breathability, ease of cleaning, and longevity (Million Mile Warranty if properly maintained). The military has maintained a contract with K & N for use in Apaches and other ground based war vehicles especially in the sandy middle east environments.

 

Shouldn't hot weather reduce MPG due to the less dense air?

 

Less air = less fuel thrown into combustion which equals slower car/increased fuel mileage.

 

Where did you buy it from?

 

Hard to believe of that kind of mileage increase.
In a time when auto companies are having a tough time meeting government CAFE numbers,you would think all vehicles would have a K&N type filter if it actually increased mileage.

 

Exactly.

Many car companies are spending -billions- to improve mileage on their cars. If they could do it with a $50 air filter they would be doing so.

 

The difference was noted immediately after install of the filter.

 

The measurements are by the cars computer - avg not instantaneous.
Yes I've modified my driving habits, but I did that well before the filters were installed.

On the '02 ES300 - the best highway mpg I had ever seen was 28 (avg), more normally 26.5 (Avg). After the K&N was dropped in I hit 31.5mpg (avg).

My Kids '06 SantaFe popped from 18 to 22 highway after the filter was installed.

The SC430 I seem to be able to keep around 20mpg combined highway/local now, used to drop to 16.5 combined, it does more around town because of the wife.

The IS250awd is now doing 26mpg, from 24mpg, I think i can gooose it higher with driving technique. It's hard to hold the car back.

For the hell of it, I spoke with a contact I have Lexus corporate today and passed it along. Let their engineers verify or disprove it. If it holds true, I just saved them a whole bunch of R&D $$$$$.

 

The check engine lights was probably triggered from not sealing the box properly (made sure all the clips are fastened) or they over oiled the filter. A simple way to make sure the filter does not have too much oil is to dampen the filter with a paper towel after oiling it.

Koz