I saw an ad for an air intake today saying how it can improve gas milage. I thought with more air flow, the ecu would compensate by adding more fuel causing milage to go down, but horsepower to go up.

do they give you better or worse milage?

 

well, you'll get a little bitbetter air to fuel ratio, but basically yeah, more air needs more fuel

 

if you install a cai, you will lose fuel mileage due to you liking the sound of the intake and flooring it all the time!!! Or at least i did

 

if the intake ACTUALLY increases air flow, then the engine should compensate by adding more fuel. sometimes, this creates enough power to keep the fuel mileage the same or MAYBE increase it, but id say about 90% of the time an intake will very slightly lower your mileage

 

it's a tuff debate. the reason is the control points. How far the throttle body is open and also the computer adjusting the fuel as it looks for the optimum a/f ratio. Different vehicles control in different ways.

If your driving 60 mph and the throttle was open 75% and now with the intake it only needs to be open 70%, what have you lost?

I don't know the real answer to the question. just that it's not an easy question.

 

I have ran K&N filters, and FIPKs on all my trucks I have ever owned. Everyone I saw at least 1 mpg increase. I just got a K&N filter for my new ranger today so I'm hoping that trend continues.