Forgive the newb questions, but when porting, does the engine run at a different idle? Does it improve rev response? How much gas mileage have any of you seen with a ported motor and stock ecu?

Porting is like changing cams on a piston engine.

Before I did a street port on mine, I got about 18 mpg messing around town with good low end and somewhat good midrange with flat top end. Now it still gets 18mpg around town but with the same good low end, much better mid range and forceful top end until about 5500 rpm, after which the stock exhaust manifold gets too restrictive causing a somewhat shallow upper power band.



The car still idles at 750 as smoothly as before, and it has no trouble starting up. I did a medium primary port, medium - large secondary, and large sixth port. There are pics of it somewhere around here if you feel inclined to search for other street porting threads. As far as I am concerned, street porting insofar as what I did to my NA has no drawbacks, other than emissions perhaps, but I haven't had to test that side of it because of where I live.

It depends on the port