Ford Coyote Engines. Jim Smart
of the way to improve high-RPM induction flow.
The Coyote continues with traditional port injection because Ford engineers felt it didn’t need direct injection at this time. A lot of development work is yet to be done if you’re considering direct injection. The Coyote’s cylinder head castings have a provision for direct injection. The block is strong enough to support direct injection. Ford just isn’t there yet.
In back are these CMCV actuators for 2015–up, one for each cylinder bank. Instead of the charge motion control valves being plates, as they were on the 4.6L engines, they are flaps that change intake air flow to improve idle quality and low- to mid-range torque. When you mash the throttle, they move out of the way to improve high-RPM performance. CMCVs can change intake runner length depending on driver demand.
The Coyote’s exhaust system is just as critical to power and efficiency as the rest of the package. Headers might not seem important in the big picture, but they are important and were a great area of focus for Team Coyote. The Coyote has short tri-Y headers that were thought out painstakingly and well executed. Engineering had to fight for them. Bean counters didn’t want them because they cost twice as much to produce as cast-iron exhaust manifolds, yet they were crucial to emissions, power, and fuel economy.
Because the Coyote’s factory shorty header is extremely unique in its approach, it has enabled the Ti-VCT to produce more than 400 ft-lbs of torque. Try that with your 5.0L pushrod small-block. You can get horsepower all day long. Torque is another story and a huge challenge.
The Ti-VCT Coyote was conceived for high revs, and with that dynamic comes huge oiling system demands. The Coyote must sustain sufficient lubrication to 7,000 rpm and beyond and under extreme driving conditions. Ford opted for an 8-quart oil pan and a suitable windage tray/pan gasket combination. This is all good for keeping oil pressure and volume on target. It also created the huge challenge of oil drainback because oil arrives at moving parts in abundance. Ford solved this problem, and others, with crankcase breathing chimneys. These PCV chimneys improve both drainback and crankcase ventilation.
Close attention was paid to the Coyote’s cooling system, which focuses on exhaust valve cooling along with other extremely hot areas of the engine. Ford calls this cross-flow cooling, which is different from the conventional cooling that the 4.6L and 5.4L Modulars employ. Cross-flow cooling routes coolant upward through the block where it enters cylinder heads at the exhaust valves for excellent heat transfer and reduced operating temperatures. Coolant runs through a long manifold cast into the cylinder head at the exhaust valveseats. This keeps detonation issues to a minimum and durability high.
Ford’s 5.2L DOHC flat-plane crank V-8 is billed as the highest-revving factory V-8 in American automotive history, with 526 hp and 429 ft-lbs of torque on tap. It spins to 8,250 rpm but shuts off at 8,000 rpm. The sound of the 5.2L Voodoo is clearly different from the sound of the Coyote Ti-VCT V-8 it is spawned from. With flat-plane crank technology the Voodoo makes a snarly, raspy bark from its tailpipes. At high RPM it emits a goose bump–inspiring scream unlike any American V-8. On the surface, the 5.2L Voodoo looks like its smaller sibling, the 5.0L Coyote. Beneath the aesthetics it is a different animal entirely.
The 5.2L Voodoo has been conceived for the Shelby GT350 to make it a breed apart from anything else on the road. Jamal Hameedi, chief engineer at Ford Performance, describes the 5.2L flat-plane V-8 as a product for which every single performance target has been met, including a broad torque curve, crisp throttle response, and no weight increase.
The flat-plane crankshaft approach is nothing new, especially when it comes to exotic high-end European sports cars. However, it is surely a fresh idea for Detroit. When you look at more traditional cross-plane–crank American V-8s with 90-degree reciprocating intervals opposite the counterweights, the flat-plane approach puts pistons and rods exactly 180 degrees opposite the counterweights instead of the traditional 90 degrees. The result is a completely different sound from the traditional V-8 roar that you are used to hearing. The difference in sound comes from exhaust pulses, which happen at different intervals than with a cross-plane–crank V-8. Cylinder banks fire alternately creating a buzzy exhaust harmony on a par with European exotics. At wide-open throttle at high RPM, it sounds like a Ferrari.
This is the 5.2L Voodoo engine in a 2015 Shelby GT350. Although the 5.2L engine is based on the 5.0L Ti-VCT Coyote, it is not the same engine by any means. Its flat-plane crank design is only the beginning of what makes this engine different from any other American V-8. Traditional V-8s have a cross-plane crank with huge counterweights surrounding rod journals at a 90-degree angle. This makes for smoother operation, but a heavier crankshaft. The 5.2L’s flat-plane crank weighs less and gives this engine a snarly buzz at high RPM, like European exotics. This comes from rod journals being 180 degrees opposite of where the crank looks flat, hence the term “flat-plane” crank.
What flat-plane technology means for you at your backside is better exhaust scavenging and a notable increase in power. Even more, it enables Ford to produce a lighter crankshaft with a crisp, snappy throttle response that allows a 7,500-rpm top out, with peak torque coming in at 4,750 rpm. Redline (fuel shutoff) comes at 8,000 rpm.
The flat-plane 5.2L engine really is a racing mill that you can enjoy on the street because it delivers excellent fuel economy on the open road with a 3,000-rpm torque curve. Yet it makes 526 hp at wide-open throttle. What this means for you on the track is brute torque coming out of turns with an incredible blast of power coming down the straights. This is an engine that loves to rev.
Ford says torque begins to come on strong at 3,750 rpm with peak at 4,750. To achieve 5.2L, Ford infused a slightly oversquare bore and stroke ratio at 94.0 × 92.7 mm. This author wound up behind one of the 5.2L Voodoo Mustang engineering prototypes at a traffic light in suburban Phoenix, Arizona, for an intimate experience with the 5.2L Voodoo’s exhaust tips.
Here’s the 5.2L Voodoo head on. Although, at a glance, the Voodoo resembles the Coyote, there are many differences, including a more advanced induction system, GT350-specific cylinder heads, a Voodoo specific block, and more. (Photo Courtesy Ford Performance Parts)
The Voodoo is clearly a different experience because it is buzzy like a European exotic at high RPM. However, through the revs it resembles an American V-8. It is very Jekyll and Hyde as it makes its way to 8,000 rpm. At peak horsepower, it makes a European V-6/V-12 buzz like you’ve never heard in a Mustang. Compression ratio is an astonishing 12.0:1.
Even though there are positives to flat-plane technology, there are also negatives. If you’re married to the traditional sound of a cross-plane–crank V-8 engine, the flat-plane–crank pulse will seem foreign to you. Harmonics issues also exist to some degree with flat-plane–crank engines when displacement rises above 4.5L. Low-end torque also suffers with flat-plane–crank engines. The 5.2L Voodoo isn’t big on low-end torque. However, this isn’t an engine designed or engineered for low-end torque. It is a race-bred high-end street/track engine that does its best work at mid- to high RPM.
The 5.2L “flat-plane” V-8’s induction system is completely different from its 5.0L sibling’s. This is an engine designed for high-RPM operation,