Does changing the intake to either the Z intake or another cold air intake have any effect on gas mileage? Less or more?

 

The point of a new intake is to allow more air flow than stock. This leans the A/F ratio and should make for better gas mileage if you are driving the same pattern as before. On the other hand, if you find the new sound intoxicating and are going WOT more often your gas mileage will probably be worse.

 

Got the Stillen CAI and Z-Tube + HyperGrounding Kit. My mileage went from 17.4 to 19.8. It DOES make a difference.

 

The Obd2 ecu constantly [every rpm] adjust the injector opening time to EXACTLY average a 14.7 AF ratio at idle and cruise......the more air you injest the more fuel you MUST use.

Some mods can upset the MAF calibration curve so it has increased errors, but these errors are quickly [like in a second or less] noticed and corrected for by O2/ecu changes.

Nothing you do [cheap [under a few thousand] easy mods] at idle or cruise can materially affect the CRUISE [highway] fuel consumption other than installing different diameter tires with changes the rpm at a constant speed.

The factory would kill for a 0.25 mpg improvement as they could save the taxes they pay for CAFE.

 

I know the mods theoretically shouldn't alter the mileage, but I'm actually getting about a 1 mpg improvement with the Stillen intake/exhaust, but driving more agressively.

bd