Well it seems like my MPG has been dropping since I installed the K&N Filter. Maybe the ECU still needs to calibrate for the increased airflow. Has anyone else who's installed the K&N filter noticed if their MPG have been dropping?

 

I'm no mechanic, but shouldn't that be expected? You are increasing the air flow, so the ECU would adjust and increase gas to maintain the proper air/fuel mixture. Or maybe I'm completely wrong.. ha ha

 

i never had good mpg in the first place!!!

 

lol agreed i get 310km/tank. less if i take it to a track or autox

 

my mileage has gone up with the Amsoil filter. I was able to get to 28.8 for 15 miles until I decided that gas was so cheap I could use up a few gallons my long term long will tell for sure.

 

i literally have been getting about 11 combined since ive got the car... although ive never taken it easy either

 

Wrong. In theory you should be getting better gas mileage. It is probably due to your foot and your driving style, unless this filter is really restrictive.

I would reset your ECU by pulling the fuse or disconnecting your battery for 30 minutes.

 

Thanks for the correction, but can you explain? From my understanding, if the ECU does not compensate by adding fuel to maintain the proper mixture ratio, then you would be running lean. Am I confused?

 

What are the differences between amsoil and k&n?

 

Ummm. No. Airflow is regulated by the throttlebody, not the airfilter. If you push harder on the throttle your gas mileage will drop. In theory, if the filter is a significant restriction, a less restrictive filter will improve economy by reducing pumping losses. If the filter isn't the biggest restriction in the system changing it will make no difference to anything.

I seriously doubt the filter is the biggest restriction. I also know for a fact K&N does not filter as well as any OEM filter because the OEM filter protects the manufacturer from replacing your engine. If the K&N filter is defective in any way, they'll replace the filter, but not your blown engine. Just something to think about when evaluating aftermarket parts of any kind - what will they replace if their piece is bad and toasts your engine? Few, if any, will replace your engine, they'll only replace their defective part. Manufacturers don't get this luxury as they are responsible for the entire car, so their solutions tend to be a lot more conservative.

 

Leave it to Lobuxracer to hit you with some real world knowledge. Thanks man. I always respect your input.

Still, how much damage could a K&N filter really cause to an engine if properly maintained?

 

is this filter from K&N come with oil spray bottle to cover it every 4k-5k miles? if so that may causes problem. I read from another forum whose members used K&N filter, they complained that oil had dripped down and covered the MAC reading of the air box causing some problem.

 

i truly think the best thing for intake wise.. is the K&N filter.. it appears to work

 

Has anyone dyno tested a K&N vs OEM?

 

K&N hasn't released anything for the IS-F, I checked last night.