Guys, Turbo's should be more thought-of as displacement on demand. here's a simple equation:
For every 14.7 psi of boost, you've added 1 atmosphere.
The Ford ecoboost tops out at about 13 or 14psi of boost on the 3.5 motor. So the motor's effective displacement would really be about 6.6 or 6.8 liters. That's a big engine, and being force-fed means earlier delivery of power.
So for any displacement on demand (DOD) system, it is more efficient the less displacement you use. That's the idea anyways. So if an ecoboost can stay off the boost, you're only using 3.5 liters worth of engine. When a Hemi 6.4 liter shuts off half its cylinders, you are using about 3.2 liters worth of engine. Each approach has its plus and minuses. I am just curious as to whether or not the 2.7 will be really stretched out and if it can stay off the boost to return the economy. I also wonder how much Ford's self-rating EPA method will differ from Motortrend's real MPG test.
