Optimal Speed for Optimal MPG?

[Slazenger14]

Have there been any tests or data found to see at what speed (or RPM) the Fiesta gets the best MPG? I found that between 60-70 MPH I can stay around 38 MPG (that's with some city driving, too), but anything higher than 70MPH on the freeway hurts. This is assuming that everyone is using E10 gas when performing these tests. Any input or ideas?

[billnchristy]

50 will get you about 50.

50 will also get you the following:

flipped off
run off the road
peoples asses pressed against their glass

etc.

[missourimule]

I can't speak for everyone but I found that at 66 mph on I30 from Little Rock I was showing 46.0 on the computer. That seemed to be the "sweet" spot for me. When the trip finished up with combination driving it came to an average of 39.6 mpg.

[FXSTi]

If you are really interested the best fuel economy, look into the clean mpg forum. They managed to pull 63 point something or other for 2600 miles. It involves some pretty radical changes to your driving though. Even if you don't use all of their techniques you might still take away some things that will make your driving more efficient and your mileage better.

If you decide to pursue it, try one new technique at a time so that you can see what it does and so that you get it down pat before you start on the next. Also, get an Ultra Gauge or Scan Gauge.

CleanMPG Reviews the 2011 Ford Fiesta - CleanMPG Forums

[jwalk5124]

The best MPG you will get on the freeway is probably what the Minimum speed limit is.

On flat roads your best MPG will be when your at the lowest RPM in the highest gear. Not sure what speed that is in manual but in the automatic that is right around 40 MPH.

You can get 60 MPG or higher driving at that speed... but everyone will hate you!

When driving 55 on the local highways in Michigan I can get around 51-52 mpg (my trips are never long enough to keep my MPG that high though)

[sirheck]

One thing i plan on doing once i need new tires is to plus size
to the 205-50-16,s from the 195-50-16,s as they are a little
taller and will drop my RPM,s at highway speed little as well.

[Pennut]

Originally Posted by sirheck

One thing i plan on doing once i need new tires is to plus size
to the 205-50-16,s from the 195-50-16,s as they are a little
taller and will drop my RPM,s at highway speed little as well.

But going to a wider tire adds more rolling resistance so it will not give you better mileage.

I have no problem getting 40+ mpg on the highway in my auto SES hatchback keeping it around 65 mph average. I keep my tires at 35 lbs.

[wmussatto]

Going to a taller,vs. wider tire/wheel combo should, in theory have the effect of increasing your gearing and thus your MPG. Of course YMMV.

[billnchristy]

It will also throw off your gages so you will never know what is true.

[sirheck]

A 205 tire isn't that much taller than a 195, it may drop my RPM,s
by say 100 to 200 at speed. That might get me an extra 1 mpg if
i am lucky. The width is probably not even measurable as far as
rolling resistance is concerned.

The speedo difference is probably or maybe 1 mph difference????