Here's the sound of Ford's new 6.7-liter Power Stroke diesel, or at least in the clip's second half. The first half's also the new diesel, but without the two pilot injections. That's why it sounds like an old 7.3-liter diesel.
The new engine can inject fuel up to five times per stroke. There's two pilot injections to quiet the engine that also help prepare for the main (third) injection. After the main injection, two more injections can be added as needed. The first for a little extra torque and the second — on the far end — for kicking off the diesel emissions catalysts.
The result? It's one quiet, quiet diesel engine.