It seems like my MPG has gone down since I bought a K&N drop in filter for the stock airbox. My first two tanks were about 25 mpg with mostly in town driving, my normal pattern. Then I got the K&N and my MPG has been about 23 MPG since with the same driving pattern. This morning I put the stock air filter back in to see how my MPG is the next couple of tanks. I bought the 3 because the 12 MPG my Hemi Ram get's was really starting to add up. If the K&N actually hurts MPG, I'm going to leave it out. I'm sure I was lucky if I got another 1-2 HP from it and the drop in MPG isn't worth it for what I bought the car for. Anyone else experience this?
Jim

 

no. I've got a 2006 3s with 31800 miles, i do alot of driving. i put the K&N drop filter in it when it had 15k on the odometer. There was a slight boost in fuel economy (i calculated it to be about 2mpg more than what i got with the paper filter) anda little performance boost - nothing to jump up and down over.

Without driving till it putters out , I get about 390-410 ish miles per tank of gas, doing a majority of highway driving - but a fair amount of regular backroad driving.

 

strange... maybe the filter is clogged up with the oil from the filter??
or is it a dry filter??

i have a cold air intake, and cat back exhaust, and i can easily get 400km's to the tank with normal city driving, before i was getting 300 km/tank while driving like a grandma....

i guess some ppl just have different luck....

 

I thought I read that CAI and Exhaust would actually LOWER your mpg. Now you make me want to get all the good stuff again now.

 

I put one of these in @ around 12K and didn't really notice any difference until I installedan exhaust. My mileage has remained relatively stable throughout the changes I've made.

 

One explaination is this:

The engine managment system will work to maintain the same air/fuel ratio before and after any mods. More air = more gas. The efficiency must increase enough to offset this fact. I suspect it has something to do with driving habits.

 

You mean my aggresive, heavy foot isn't helping?
LOL!
Jim