Building the most impressive naturally-aspirated powerplant in Ford’s history–regardless of displacement–was no easy feat, but Team Mustang did it with only 5.2 liters, an outside-the-box approach, and thousands of man-hours of development and calibration, culminating in this all-new powerplant designed for the 2016 Shelby GT350/GT350R Mustang platform that debuts later this fall.
Earlier today, the long-awaited final power numbers, along with many finalized details of the engine’s construction, were released for public consumption by the development team.
Back in January, after catching a cutaway of the engine at the North American International Auto Show in Detroit, we speculated about some of the details on this engine, and now we have the real-deal info straight from Ford. In an impressive feat of corporate secrecy, they have managed to keep many of the details under wraps to this point, releasing information on their own terms despite our arm-twisting and groveling for more.
The engine, unique to the GT350 program, carries a stratospheric 8,250 rpm redline and produces an incredible 526 horsepower and 429 pound-feet of torque. A flat-plane crankshaft–usually reserved for only the most exotic machines–helps the engine to achieve these performance figures with relative ease.
“The Shelby GT350 program began with a clear objective – create the most balanced, nimble and exhilarating production Mustang yet,” said Jamal Hameedi, Ford Performance chief engineer. “Every change we made to this car was driven by the functional requirements of a powerful, responsive powerplant. The high-revving, naturally aspirated 5.2-liter flat-plane V8 delivers on every target we set – high horsepower, broad torque curve, aggressive throttle response and light weight.”
The engine is not only the most powerful naturally-aspirated engine to ever go into production, it’s also the most power-dense, with an incredible 102 horsepower-per-liter of displacement. For comparison, the only engine in memory produced by Ford–the legendary 427 SOHC race-oriented mill–to even come close to this figure managed a measly 88 horses-per-liter.
According to the company, millions of possible intake manifold, exhaust configurations, and camshaft profiles were simulated before the dimensions of these critical components were finalized.
The engineering team settled on the design of the flat-plane crankshaft for one main reason; to improve the exhaust-pulse separation by allowing a firing order to alternate between banks, which carries the latent benefit of improving engine breathing to permit more power from a smaller package.
Maximum power is achieved at 7,500 rpm, with peak torque arriving at 4,750 rpm, but more important, the engine calibration provides 90 percent of the available torque from 3,450 rpm through 7,000 rpm, with nearly 3,000 rpm between the torque and horsepower peak. This should translate well to the racetrack, where we expect to see the GT350R dominate in many road-racing classes as the cars start to arrive in the hands of some of the country’s most capable racers.
In the all-new Ford 5.2-liter V8, the connecting rods attach to the flat-plane crankshaft at aligned 180-degree intervals – creating what looks like a flat line of counterweights when viewed down the axis of the crankshaft. This crankshaft configuration improves cylinder exhaust-pulse separation, improving airflow and increasing power.
Cylinder bores measure 94mm (3.700-inch) with the forged-steel, gundrilled crankshaft’s stroke topping out at 93mm (3.661-inch) in an oversquare configuration. The aluminum block uses Ford’s now-perfected and patented plasma transferred wire arc cylinder-liner technology to keep weight down while improving performance; the use of this design allows them to forgo heavy cast-iron cylinder liners.
12.0:1 compression is standard, reminiscent of the heyday of lead-fueled big-block engines.
Alternate views of the work-of-art forged-steel flat plane crankshaft.
For performance and consistency reasons, CNC-machined cylinder heads sit on top, filled with camshafts measuring .551-inch lift for both intake and exhaust; a healthy number for a four-valves-per-cylinder engine. Lightweight intake valves feature hollow stems, while the exhaust valves are sodium-filled to improve heat-transfer. An 87mm throttle body allows air into the engine.
“A new Mustang as exceptional as the Shelby GT350 deserves an equally extraordinary engine,” said Dave Pericak, director, Ford Performance. “The all-new naturally aspirated 5.2-liter V8 perfectly fits the balanced dynamics of the Shelby GT350, and we believe this new engine will become a performance legend.”
One question has not been answered to our knowledge as of this point in time. Will there be a crate-engine part number? Listen to that incredible exhaust note!