Originally Posted by kam327
Well there's a documented 2mpg gain through the use of the shutters, LRR tires, aero wheel covers, spoiler, and omission of Select Shift. Do you think the shutters are responsible for all of that gain and the rest is a waste? I was merely giving the shutters credit for half that gain, and even that may be being overly generous.
The shutters are not only available on the SFE package though. The 2mpg gain is in all reality due only to the LRR tires, wheel covers and spoiler. SelectShift has nothing to do with it.
The shutters are available and were supposedly standard on several if not all Foci (now it's all, not in 2011) and were most likely part of the EPA testing procedure as well. So I think expecting decent gains from them is entirely plausible. They reduce drag at highway speeds and bring the engine up to operating temp more efficiently. These two things alone I can imagine having a decent impact.