So, here's the question, I've been puzzling over it for a while. Will increasing airflow and reduce backpressure by getting a larger exhaust/header increase gas mileage? What about port and polish on the intake? If so, why did honda make the hf/cx/vx intakes and exhausts so damn small? I'm wondering if I should buy a header/exhaust thing, but I'd only want it for gas mileage yasee. Thanks in advance.

 

Allowing the motor to breathe easier will give you better mpg. So long as you dont increase the duty cycle of the injectors your mileage shouldnt go down. However too big of an exhaust can cause a problem as bigger pipe = more air = harder to push. The problem most people have when they throw on i/h/e is they tear *** all over the place because of the increase in power so mpg is lowered.

Just an intake on my 90dx got me 2-3mpg more on average.

Oh, and honda makes them small to reduce noise, plus performace isnt #1 on an economy car.

 

Ah thanks, thinking about testing it out then for the old gassavers. :-)

 

I just read that torque will increase mpg, while hp will not, is there any opinion around here on that?