I am wondering when you reach a point that the turbo will be needed just to get the truck rolling in stop and go traffic. I wonder if the 2.7 has reached that point and that maybe the 3.5 is in the sweet spot. 18.5 mpg is what motor trend says about the 2.7 hwy. That's not much better than the 3.5.
The V8 deactivated cylinders will cause friction and reduce mpg. But when you want power there will be no affect. The corvette gets 29mpg hwy. And will do over 170 mph.
The new v8's don't just deactivate the fuel injector. It also does something with the valves to reduce compressor losses. They also don't deactivate the same cylinders, they alternate them so that a cylinder won't get a wash with oils I guess. All this stuff is handled electronically now, not a great amount of mechanical change. So is pretty simplistic mechanically when compared to engines of the last decade.
