Adam R wrote:
otrfun wrote:
8iron wrote:
ib516 wrote:
That's the thing with an EcoBoost. You can only have one. Eco, or Boost. Your right foot chooses.
Could not the same thing be said for virtually every internal combustion engine with a throttle ever built? Would a statement like " you get to choose one" be more accurate?
I believe what ib516 is trying to say is, there's a very fine line between Economy and Boost with the F150 Ecoboost.
A few years ago I had the opportunity to drive a number of different F150 Ecoboosts on some long-distance trips. The only way I could consistently get 20 MPG highway was to keep them at 60 or below. As soon as I nudged any of them above 60 MPH, the MPG's dropped precipitously. Not very linear (in terms of MPH and MPG) from my experience.
Wind resistance, i.e. speed, kills mileage. In looking at the Drag equation, when doubling your speed, it requires the amount of power used to be cubed. Per wiki below:
"The power required to overcome the aerodynamic drag is given by:
P_d = \mathbf{F}_d \cdot \mathbf{v} = \tfrac12 \rho v^3 A C_d
Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW). With a doubling of speed the drag (force) quadruples per the formula. Exerting four times the force over a fixed distance produces four times as much work. At twice the speed the work (resulting in displacement over a fixed distance) is done twice as fast. Since power is the rate of doing work, four times the work done in half the time requires eight times the power.
Bottom line is that a 10 mph increase could easily cut mileage by 20% or more and it just gets worse the faster you drive.
Adam
Thanks for the explanation.
My bad. I guess I could have done a better job of putting my reply into perspective.
My 5.7 Tundra, with no wind, level ground, 2000 ft. elevation, will get 18 mpg all day, all night at 75 mph. Been doing it everyday for the last 3 years. Hand calculated.
Every F150 Ecoboost I've driven gets the same 18 mpg at 75 mph. Same conditions except for elevation, which was typically lower. Also, hand calculated.
My 5.7 Tundra has an EPA highway rating of 18 (2wd). The F150 Ecoboosts I drove had an EPA highway rating of 21/22 (4wd/2wd).
Below 60 MPH the F150 Ecoboost gets significantly better MPG's than my Tundra.
My point: Once the F150 Ecoboost goes into boost (above 60 MPH) the MPG's drop precipitously. Far from linear from my experience.
