newscionboy

Hey there I just installed my AEM CAI last week, and i thought that it would give me better gas milage. after installing it the range of a full tank went down from 335 to 255. I was wondering if there was a certain amount of time before i would see the effects of the CAI. I know that i might be driving it a little harder with it on but still i lost almost 100 miles. if anyone has any insight to this it would be much appreciated. thank you

TuningIsLife

CAI, will not affect gas milage that much, what you are talking about is a difference of 25 mpg (14gal tank) to 18mpg. If anything it would make it drop by 1 or 2 mpg.

ScionFred

iTrader: (1)

I can think of 2 possibilities:

1) You didn't disconnect your battery to reset the ECU after installing the CAI and your A/F mixture is rich.

2) Like me, after installing your CAI, you enjoyed the new engine sound at higher rpms so much that your driving habits changed and gas mileage tanked. The same thing happened to me but after the thrill wore off my gas mileage returned to where it was before.

rdfxb

Just like when you get a new exhaust, your freaking gas mileage goes out the door.

batwing

iif you drive moderately, not spirited, the mpg will not be affected as much. when you step on the car alot, that will going to force engine to mix more fuel with the massive air flow, making the fuel to burn...

draxcaliber

alright, there is some ignorance in this thread...

a cold air intake, or any performance intake will not improve MPG.

a gas engine needs two things to run, air, and fuel. gas is the power source, and air unlocks it. you need a ratio of about 12 parts air to every one part of fuel.

if your engine just dumps fuel without enough air, it will run rich and bog down. so you need to get more air.

so the idea behind a cold air intake is to draw in more, colder, denser air so your engine can then add more fuel, to maintain that constant ratio of 12 to 1 for your a/f ratio.

exhaust will have no effect on your MPG because it is just a pipe that channals the exhaust gases out of the engine. it has nothing to do with the amount of air or fuel the engine uses. the goal of high performance exhaust is to minimalize back pressure and maximize exhaust gas velocity and create an additional vacuum effect to help pull in fresh air when evacuating the exhaust gases.

Bigfieroman

Intakes reduce the suction the engine needs to generate in order to pull in the air. Exhausts reduce the back pressure and encourage efficient airflow. These effects both reduce pumping losses, leaving more power available to move the car. Now, the effect of both of these on fuel mileage is minimal, but assuming ALL OTHER CONDITIONS remain the same, including throttle usage, fuel mileage will increase over the same course. Basically, if they put on a low restriction intake and exhaust and then ran the car through the EPA tests (EVERY variable is completely controlled), you might see a gain of about 1 mpg or so.

So, why don't manufacturers design the intake and exhaust to be low-restriction to begin with? 4 reasons:

Noise
Cost
Emissions
Engine behavior/torque curve/refinement