I agree with what chandler just said. But also it is possible your intake reduces your gas mileage. (not in a bad way necessarily). Think about it. If you put more air into the car the only way it benefits you is if you get a bigger explosion. Sometimes maybe the mixture is too rich already so putting more air in just gets you that bigger explosion. Or sometimes it's lean and adding even more air means you need more fuel. Sure you'll get more hp, but you often burn more fuel too. It's very engine and setup specific.

But either way I still stand by that the increase in hp(mostly done because of the introduction of the 109 hp Honda Fit into the honda line)is the biggest reason for the decrease in mpg on the new civics.

 

rather than the increase in hp id have to agree it's the increase in engine size

 

and id also have to agree with the weight of the car being a huge factor.
but the intake is not going to decrease gas mileage. rather, it will increase gas mileage. the intake has better flow than the stock, putting less strain on the engine and the engine has to work less hard to pull air in.

 

Okay, this thing won't let me respond the way I want. But bro, you're a little misguided as to what your intake does and why.

A better flowing intake will get air in the engine easier. But that is not to say the engine is using up the work produced inside the engine in order to bring in air. Putting more air in the engine allow for the consumption of more fuel. If the ecu aims for 50/50 ratio and you give it more air, it's going to put more fuel in to compensate. Sometimes this can give you better or worse mpg. With that said, all I said is that it's possible your intake lowers your mpg. Which doesn't really mean it's bad, it just means your burnign more fuel. It could be for more power or for other reasons. Does that make sense bro?

 

I just filled up my Civic for the first time. I am not exactly certain about the mileage because even though the dealer filled the car up they got the car for me from another dealer about 30 miles away. Best estimate was 25-31 mpg, next time it will be accurate since I am doing the recording. But I have to say I am satisfied, I am home this week so it was all city miles and I idled alot showing the car to my friends, if this is the worst I bet I will do great on the highway. Thanks for all the input, this is a great forum!

 

My 06 LX Coupe gets around 35 - 36 if I am doing 70. If I slow down and drive around 62 - 64 mph I get around 39.
The best I got was 41, and the worst so far is around 32.

Sure beats my Silverado I traded in.

Drive safe.

 

Yeah, you're car mileage will definately go up because the computer has to get used to your driving habbits during the break in period. You will notice an increase in each fill up for the next couple thousand miles or so.

 

lol the new mpg estimates are stricter, thats why it is lower

 

hey guys, my 05 civic lx (non vtech) gets 33mpg local and 40mpg hiway with K&N free flow filters. I'm so satisfied with it but I'm about to sell it coz I'm getting the 8thgen coupe.

I believe de-restricting airflow has only a very small effect on the MPG. It's really your foot.

 

I have had my car for about six weeks and am getting over 30 most of the time. The best was 34. I am happy with that, I expect better after I break it in, I have 1900 miles right now. Thanks for all the responses.