2016 FIST rated at 33 mpg highway

[roto23]

How could it get 2 mpg less when it's the same car?

 

[pelotonracer2]

How could it get 2 mpg less when it's the same car?

That seems more accurate. I can average 35 mpg on the highway at about 60 mph. Most highways have speed limits of 65 to 75 mph... even 80 mph in some states.

With that said they could have made some tuning changes or changes with emissions compliance. Even the changes in tire specification, weight can effect avg mpg ratings. The changes in city/hwy estimates happens on a regular basis from model year to model year.

 

[roto23]

Is your 35 mpg average with all those performance mods?

 

[pelotonracer2]

Is your 35 mpg average with all those performance mods?

Yes, fuel trims should not change much with a fully warmed up engine during highway driving despite the mods. If I'm a little more creative, I can achieve 42-44 mpg for like 45-50 mile stints. heh

 

[dyn085]

How could it get 2 mpg less when it's the same car?

Ford probably changed the members to be less optimistic after being hit with having to refund Fiesta owners earlier this year due to the previous estimated fuel mileage.

Yes, fuel trims should not change much during closed loop highway driving. If I'm a little more creative, I can achieve 42-44 mpg for like 45-50 mile stints. heh

The FiST operates in closed-loop 100% of the time.

 

[pelotonracer2]

Ford probably changed the members to be less optimistic after being hit with having to refund Fiesta owners earlier this year due to the previous estimated fuel mileage.

The FiST operates in closed-loop 100% of the time.

While I haven't messed with the FiSTs ECU, I have on other vehicles... it usually only goes into closed loop mode when when it's fully warmed up and running at normal operating temps. During warm up usual ECU strategies adjust fuel and timing (usually adding more fuel). The FiST doesn't do that?

 

[CanadianGuy]

In Canada they did something similar that the rating for a 2014 is much higher than the rating for a 2015. The reason is the government made a mandate to change the testing to reflect real workld and attainable numbers. Not the best numbers under the best conditions going downhill with a tail wind. Similar for US.

read:
http://www.popularmechanics.com/cars/a5617/new-2016-cafe-standards/

 

[JasonHaven]

https://www.fueleconomy.gov/feg/fe_test_schedules.shtml

It's pretty easy to beat current ratings if traffic is reasonable.

 

[dyn085]

While I haven't messed with the FiSTs ECU, I have on other vehicles... it usually only goes into closed loop mode when when it's fully warmed up and running at normal operating temps. During warm up usual ECU strategies adjust fuel and timing (usually adding more fuel). The FiST doesn't do that?

You're defining open loop and closed loop incorrectly in your discussion and response. The FiST always refers to the wideband O2 sensors for fueling. We have the tendency to refer to 'open loop' when discussing WOT tuning, but that's only for discussion because the FiST is never in open loop.

 

[pelotonracer2]

https://www.fueleconomy.gov/feg/fe_test_schedules.shtml

It's pretty easy to beat current ratings if traffic is reasonable.

Yes but I wouldn't say "easy".. it takes some work and concentration. That's not really normal driving. heh In my experience, to meet the 2014 highway mpg estimates, I had to drive 60-62 mph with the cruise control on in perfect weather conditions (ie low or no wind), super flat roads... little or no traffic... on a low-ish temp, high barometric pressure day to achieve 35 mpg. I can even hit 36-37 mpg in some instances if I am REALLY careful using various driving techniques. I can also achieve 43-44 mpg drafting a semi with the same techniques (good to know if you are getting low on gas with no station in sight..lol).

 

[JasonHaven]

Yes but I wouldn't say "easy".. it takes some work and concentration. That's not really normal driving. heh In my experience, to meet the 2014 highway mpg estimates, I had to drive 60-62 mph with the cruise control on in perfect weather conditions (ie low or no wind), super flat roads... on a low-ish temp, high barometric pressure day to achieve 35 mpg. I can even hit 36-37 mpg in some instances if I am REALLY careful using various driving techniques. I can also achieve 43-44 mpg drafting a semi with the same techniques (good to know if you are getting low on gas with no station in sight..lol).

I regularly get 38mpg on the highway setting my cruise control to 65

But then again, I'm very much stock haha

 

[pelotonracer2]

You're defining open loop and closed loop incorrectly in your discussion and response. The FiST always refers to the wideband O2 sensors for fueling. We have the tendency to refer to 'open loop' when discussing WOT tuning, but that's only for discussion because the FiST is never in open loop.

Mmmmm k, I changed my initial reponse. Hopefully it makes more sense without open/closed loop.

 

[pelotonracer2]

I regularly get 38mpg on the highway setting my cruise control to 65

But then again, I'm very much stock haha

You must be using the avg mpg monitor. It is not very accurate.

 

[dyn085]

Mmmmm k, I changed my initial reponse. Hopefully it makes more sense without open/closed loop. [[emoji14]]

It does. Without tuning changes the FiST will always hit the same target lambda regardless of mods added. This is why, for the most part, people don't see much of an increase without a tune when adding parts.

 

[JasonHaven]

You must be using the avg mpg monitor. It is not very accurate.

I have an OBD dongle and an app that pulls data from it *shrugs*

Manually calculating on my previous car, I regularly beat the mileage ratings as well.

 

[me32]

How could it get 2 mpg less when it's the same car?

Maybe they rated it on on 87 octane. Cause i got 2mpg less on 87 than on 91.

 

[boombots]

Interesting. I can pull 35 at 65 mph. With my eco tune and cruise at 76 in the mountains I pulled 35. On the flats coming out of the mountains and into NC, 70-75mph for the last 100 miles of my drive I pulled down 39.

I'm shocked they would lower the rating. At that point they should change the regular focus. That thing got 5 less mpg all around.

 

[Joker328]

Has anyone tried using the economy map on the AP? I was thinking of using it on an upcoming road trip (mostly highway) just to see what kind of mileage I could get. Does it make much of a difference?

 

[Brick]

I don't necessarily think it makes THAT much of a difference other than just limited boost to 5psi... which is only used for inclines in my experience when cruising. [MENTION=2876]Joker328[/MENTION]

Please correct me if i'm wrong.

My onboard mpg said 33.8 driving 90 miles of freeway sunday in 110 degree heat with the AC on. I imagine its more likely 31.5 ish just based on real word vs computer.

 

[roto23]

Interesting. I can pull 35 at 65 mph. With my eco tune and cruise at 76 in the mountains I pulled 35. On the flats coming out of the mountains and into NC, 70-75mph for the last 100 miles of my drive I pulled down 39.

I'm shocked they would lower the rating. At that point they should change the regular focus. That thing got 5 less mpg all around.

I read you can switch this tunes (maps?) on the fly. So you can switch to econo mode while driving or do you have to pull over?