As other's have already stated, Eco mode's gas savings generally come from the alteration of shift points, and throttle response. Since this was explained, and people still seem to think it does nothing, perhaps some more elaboration would help.
The savings from the former, shift points, can be more easily seen when comparing to something like Sport mode. Sport will generally keep you at a higher RPM, so you have more power available to you at a moment's notice, since the engine is spooled up already, but it will also stick in the gears longer, to try and ensure you are hitting maximum hp/tq throughout the gears (dependent on your current throttle and acceleration).
The savings from the latter, throttle response, is more apparent when compared to virtually any drive mode, although you can feel the difference way more when comparing to Sport, since it's the other end of the extreme. Essentially, if Normal mode gives you 10% power with 15% throttle input, then Eco mode may give you 5% power at 15% throttle input (or whatever number Ford decided). This is why it feels "sluggish" when accelerating. I have the benefit of seeing this much better on my motorcycle. If I am in Eco, or "Low" power mode, I can get between 200-250 miles to tank (and still outrun most things on the road). If I switch to Full power mode, which only adjusts throttle output, and not fueling or shift points, I get between 70-120 miles per tank. This is an extreme example, of course, but helps illustrate savings on a different scale.
The biggest issue that people have is that they put a vehicle (especially a rolling brick) into Eco mode, then try to drive it in the same fashion, and overcompensate because of the "feel." E.g., dropping it in Eco, then hitting the gas twice as hard as they would in Normal mode, thus virtually negating the throttle effects of Eco.
When driving at a consistent, uninterrupted, speed, you will notice less of a benefit as you are not generally shifting gears as much, and don't have much throttle/gear/RPM variation; as far as I can tell, Ford is not making any (noticeable) fuel adjustments in the Eco profile (although I'd love it if a tuner had and could share this data). At that point, it's mostly just physics. Using things like Adaptive/Cruise Control, paired with Eco, definitely can assist with MPGs over the longer trips, as the vehicle will be less aggressive when adjusting speed to reach the limiter again (due to slowing down from traffic, forceful winds, hills, etc.). You can test this yourself by dropping it in Eco, setting the speed, slowing down, then resuming CC. Do the same in Sport mode. Sport will leap forward in comparison to get back to the same speed.
Eco is touted as a fuel saving drive mode, but it's not that much savings. I'm not sure what the number is for the Bronco, but often its around 10% for many vehicles.
Tl;dr: Eco works, but it's not going to save 50% of your gas. Stop lead footing it, and drive like Eco intends to see benefits. Longer, consistent, driving in the same gear will not see much difference because #physics, especially if going higher speeds (again...brick).
Thanks for listening to my TedTalk.
The savings from the former, shift points, can be more easily seen when comparing to something like Sport mode. Sport will generally keep you at a higher RPM, so you have more power available to you at a moment's notice, since the engine is spooled up already, but it will also stick in the gears longer, to try and ensure you are hitting maximum hp/tq throughout the gears (dependent on your current throttle and acceleration).
The savings from the latter, throttle response, is more apparent when compared to virtually any drive mode, although you can feel the difference way more when comparing to Sport, since it's the other end of the extreme. Essentially, if Normal mode gives you 10% power with 15% throttle input, then Eco mode may give you 5% power at 15% throttle input (or whatever number Ford decided). This is why it feels "sluggish" when accelerating. I have the benefit of seeing this much better on my motorcycle. If I am in Eco, or "Low" power mode, I can get between 200-250 miles to tank (and still outrun most things on the road). If I switch to Full power mode, which only adjusts throttle output, and not fueling or shift points, I get between 70-120 miles per tank. This is an extreme example, of course, but helps illustrate savings on a different scale.
The biggest issue that people have is that they put a vehicle (especially a rolling brick) into Eco mode, then try to drive it in the same fashion, and overcompensate because of the "feel." E.g., dropping it in Eco, then hitting the gas twice as hard as they would in Normal mode, thus virtually negating the throttle effects of Eco.
When driving at a consistent, uninterrupted, speed, you will notice less of a benefit as you are not generally shifting gears as much, and don't have much throttle/gear/RPM variation; as far as I can tell, Ford is not making any (noticeable) fuel adjustments in the Eco profile (although I'd love it if a tuner had and could share this data). At that point, it's mostly just physics. Using things like Adaptive/Cruise Control, paired with Eco, definitely can assist with MPGs over the longer trips, as the vehicle will be less aggressive when adjusting speed to reach the limiter again (due to slowing down from traffic, forceful winds, hills, etc.). You can test this yourself by dropping it in Eco, setting the speed, slowing down, then resuming CC. Do the same in Sport mode. Sport will leap forward in comparison to get back to the same speed.
Eco is touted as a fuel saving drive mode, but it's not that much savings. I'm not sure what the number is for the Bronco, but often its around 10% for many vehicles.
Tl;dr: Eco works, but it's not going to save 50% of your gas. Stop lead footing it, and drive like Eco intends to see benefits. Longer, consistent, driving in the same gear will not see much difference because #physics, especially if going higher speeds (again...brick).
Thanks for listening to my TedTalk.
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