so i know if you take off your airbox cover you lose power because of the warm airflow, but despite that has anyone experienced better gas mileage? i had it on when i started my trip to california and after 50 or 60 miles it seemed like it used a quarter of my tank, i went to the next rest area and took it off and then the rest of the tank lasted another 210 miles. i didn't have it on for a full tank to tell you what the gas mileage was, but having it off i experienced 32-33 mpg going to and from california. anyone know why?

 

Warmer air is less dense, so you're getting less air (fewer air molecules) in each intake. Less air, less fuel, less power.


That, or it's magic.

 

Well yeah I know about the less power and I do experience it. I'm just troubled about why I'm getting really good gas mileage

 

I think the reason for the increased gas mileage is because there is more air coming in. It might be similar to getting an intake, with it leaning out your AFR's.

 

You can't change variables in the middle of a test and draw a conclusion. Since you didn't keep the cover on for a few full tanks, you don't know if your fuel economy would be better with it on/off. Also, the S2000's (and Hondas in general) fuel gauge tends to be inaccurate so you can't pull much info from going "x" miles after "y" amount of tank.

I haven't noticed any changes with it on or off because my driving habits are too random for short term testing, but Hollywood (Rice Classic) mentioned that he gained 1-3 mpg by keeping the box on. I have mine off because I'm such a ricer and it's easier to hear the car w/auto-x'ing.

Thread jack: how does the S2K determine steady state fueling? I was under the impression that the same amount of fuel is being put in regardless of air density. I could be wrong since I am just guessing, but isn't fuel determined from throttle position and manifold pressure? That would mean keeping the box on would be better for fuel economy, power, etc. because the air is denser.

EDIT - super bored at work right now...

 

ive tried this before and there was a loud ass humming which was annoying. you do get a loud growl though like if you had an intake, its just personal preference.

 

I don't really know how it works. It sounds like you know what you are talking about, so I'm just going to nod my head and agree

 

Just shots in the dark here but what about the MAF sensor and intake air temp sensor, mostly the MAF sensor?

 

Keep the cover on if you want max performance. Honda did wonders engineering this engine, can't just take their cover off and expect it to perform better than stock. It does sound cool though, I must say.

 

We don't use a MAF sensor. If you were being sarcastic, then I'm dumb