Taking a closer look at Fordâ€™s Flat-Plane-Crank 5.2-liter engine cutaway
Steve Turner and Tob
Photos by Steve Turner
Though we have seen plenty of GT350 photos at this point, Ford has avoided releasing too many pictures of the Flat-Plane-Crankshaft 5.2-liter engine. Designed to run up to 8,200 rpm and produce over 500 horsepower, there is still much to learn about this naturally aspirated powerhouse.
Unless you have been sleeping under an engine block, you have no doubt heard that the latest Shelby engine utilizes a Flat-Plane Crankshaft. A technology used by European exotics, the FPC places the connecting rods along the crank at 180-degree intervals, rather than the more traditional 90-degree positions. Doing so sets up the firing order to alternate between cylinders, which reduce exhaust overlap. This helps raise the roof on the engineâ€™s redline, and delivers a distinctive exhaust note. We are told that on the R in particularâ€”with no resonators and the cutouts openâ€”will give you chills when it is running at full song.
So, imagine our excitement when we happen upon a full cut-away display engine in the Ford display at the
North American International Auto Show.
Now details about this engine are still sketchy, but we were able to glean a few details about the Voodoo engine from studying the display. We also turned our photos over to SVTPâ€™s own forum tech guru, Tob, for his observations. Moreover, we might just have picked up a few details about the engine while we were prowling around the Ford display at NAIAS.
We hope to get more concrete details on this naturally aspirated masterpiece in the near future, but for now take a look at our shots and you just might learn something.
All hail the new king of naturally aspirated Mustang enginesâ€”the 5.2-liter V-8. We are told this display engine is pretty close to what will make production, but some components are being tweaked as you read thisâ€”most notably the crankshaft. Casual car fans might mistake this engine for just another Coyote, but as you will learn it is on a new level. Expect up to 5,000 examples of this beauty to be built during a model year.
This is our first glimpse of the heralded Flat-Plane Crank, but the reciprocating assembly doesnâ€™t look all that exotic. The pistons look much like the coated Mahle slugs we have come to expect, but the rods appear a bit beefier than even Boss rodsâ€”which were heralded as the most robust Mustang rods ever employed at that timeâ€”with more material on the big end and a more robust beam. The rods are indeed powdered metal forgings, but we are assured that they are â€œbulletproof,â€ and with the task of exceeding 8,000 rpm, that designation will surely be necessary. Moreover, those pistons deliver a 12.5:1 compression ratio. They are cooled by bulkhead oil squirters fed by what appears to be a unique oil pump wearing a 5.2 marking.
The valvetrain features beehive springs and lightweight roller followers. The camshafts look like hollow tubes with pressed-on lobes. It quite likely the exhaust valves are sodium filled. You canâ€™t see much of the heads, but we understand the CNCâ€™d ports are massive and the castings have been drilled in some spots to remove excess weight. The chambers are also CNC machined. We believe these heads might just bolt onto a Coyote, and, if so, they could become a hot commodity for those seeking maximum 5.0-liter performance.
This isnâ€™t your dadâ€™s Coyote throttle body. Nope, the FPC 5.2 wears a new 87mm throttle body to feed that large-runner intake a steady supply of air all the way up to 8,200 rpm.
Behind that bigger throttle body is a new composite intake manifold featuring tall, narrow runners designed to optimize airflow for the engineâ€™s high-revving powerband. While we couldnâ€™t see or feel the Charge Motion Control Valvesâ€”yes we molested a Voodoo engine right there on the show floorâ€”the signage on the engine confirms their existence and says they feature â€œdual actuators and solenoids.â€ This manifold should bolt up to a Coyote and offer similar performance to a CJ intake. It is rumored that this manifold was used by Ford Racing on its naturally aspirated .99 Challenge Mustang GT.
The manifold to cylinder head flange junction, the bends of the tubes, and the welds look to match the signature of the Coyote manifolds designed by Adam Christian. The collector deviates from that of the Coyote with respect to shape. This header merges three tubes into the collector (one set of tubes are paired prior to that junction), whereas previous Coyote versions had two paired tubes such that only two tubes merged at the collector.
Despite the exponential increase in NVH with the FPC, the crank damper is not an exotic, viscous-fluid-filled unit. It looks to be a rather mundane elastomeric balancer not unlike that of the current Coyote engine, but Ford describes it as select-tuned.
Where as the Trinity engine used a cast aluminum pan, the use of a composite polymer here is certainly interesting. The shape indicates it was optimized for capacity, slosh reduction, cooling, and chassis fitment.
The Voodoo engine is backed by a dual-mass flywheel and a twin-disc clutch. The pressure plate has a slightly unique shape and it might have a decreased diameter, versus the Coyote clutch, to lessen inertial forces.
It is reassuring to see that the Valhalla of OEM performance engines will re-open its hallowed halls to build the 5.2-liter Shelby engine. If you arenâ€™t familiar with the Romeo Niche Line, it features the companyâ€™s top engine builders working in pairs to create high-performance engines, like the Termiantor 4.6, the Condor 5.4, the Cobra Jet 5.4, and the Trinity 5.8.
This sign should have been reassuring for those that might be lured in by Internet rumors suggesting the impending doom of the Ford V-8 engine. Fortunately, Ford has denied those rumors, so the future appears even brighter for fans of Ford performance. Shelby GT350 5.2-liter Engine Gallery
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