The Ford 3.5L EcoBoost is a twin-turbo engine, with the pair of turbochargers helping the engine deliver its 365hp rating and 420 lb-ft of torque. That's more than 100 horses per liter or, more specifically 1.7 horses for every one of the engine's 214 cubic inches. In an age where one horsepower per cube is still noteworthy, the EcoBoost's pressurized performance is unquestionably admirable, but its torque is the truly impressive trait.
The EcoBoost's peak 420 lb-ft is achieved by only 2,500 rpm, whereas Ford's 5.0L and 6.2L naturally aspirated V-8s need to reach at least 4,000 rpm to reach their peak torque (4,250 rpm for the 5.0L). You have to look at the monster Power Stroke diesel for an engine in Ford's truck lineup that makes its peak torque at a lower engine speed: 800 lb-ft at 1,600 rpm. Even more important than the low engine speed at which the EcoBoost torque peak is achieved is the fact that it holds it over a broad rpm range. Ford says 90 percent is sustained from 1,700 rpm to 5,000 rpm. That's pretty consistent with the general performance of most turbocharged engines.