For the first time in recent memory, Ford has conceived and designed a completely new engine from scratch known as the 5.0L DOHC Ti-VCT (double overhead cam: twin independent variable cam timing) V-8 code-named “Coyote,” which was introduced in the 2011 Mustang GT. The Coyote is the first all-new engine designed specifically for the Mustang; it’s a knockout punch from America’s original pony car.
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Although the Ford Ti-VCT Coyote V-8 has been billed as a “clean sheet of paper” engine, it is only the latest evolution of the Ford overhead cam Modular V-8 introduced in 1991, first in the Lincoln Town Car. Ironically, the Ti-VCT engine doesn’t share any parts with the 4.6L and 5.4L engines and there is no interchangeability. Ford product planners and engineers looked at what they liked and didn’t like about the Modular engine family, then went to work with a goal of getting this new engine to market in just two years.
What makes the Coyote Ti-VCT different from the 4.6L and 5.4L engines are great innovations that make it a user-friendly engine. And if you’re considering a Modular engine swap, the 5.0L Ti-VCT double overhead “cammer” is the best way to go if you’re going to go to all the trouble and expense of doing an engine swap.
The Goal: A Higher Benchmark
In 2007, Ford knew it needed a world-class high-performance V-8 engine that could compete with competition from the other side of Detroit. Ford’s design and engineering team (consisting of racers and manufacturing experts) looked closely at how power is made and lost. They also looked at thermal and volumetric efficiency along with frictional loss. And they examined the limitations of the architecture of existing 4.6L and 5.4L Modular engines. The 5.0L Coyote engine was born specifically for the Mustang to set a new performance and durability benchmark. All the traditional corporate roadblocks were cleared with the mindset of getting this engine to market quickly.
The first design step toward the Coyote V-8 was the 6.2L SOHC iron-block Modular engine for the Raptor and F-150 trucks. Even though the 6.2L engine provided plenty of stump-pulling power, it was not suitable for the Mustang in terms of size and power. Ford had taken the Modular engine as far as it could for Mustang buyers.
Although the Coyote design team wanted a totally new highperformance overhead cam V-8, the basics of Modular engine architecture had to remain due to cost and retooling considerations. The new Modular engine had to come from the same production lines and from the same machinery. The 4.6L and 5.4L engines were too limited in what could be done with them from an extreme performance angle. It was an enormous challenge.
Ford’s direct injection and Ecoboost turbocharging technology were considerations for the Coyote V-8 (neither was practical or necessary for this engine early on), which gave the Coyote an economic advantage. The objective was to make the Coyote as compact as possible while keeping block dimensions close to the same size as the 4.6L. The Coyote also had to make at least 400 hp or 80 hp per liter. These expectations were huge and exceeded the capability of the 4.6L engine. The Coyote had to do what no Ford production engine had ever been asked to do before.
Ford’s goal for the Coyote engine was a much stronger block to contain and deliver the kind of power expected. It wasn’t just the factory 400-horse/400-torque goal, but also the kind of power that enthusiasts wanted once the 2011 Mustang GT hit the streets. This was going to have to be a 7,000-rpm redline engine right off the production line. Project visionaries knew they had to look far ahead into this engine’s future at not only what performance enthusiasts would do with it, but also what Ford had planned for in terms of direct injection and turbocharging. The objective was to engineer the block strong enough to begin with so they didn’t have to do it again later.
The Coyote also differs from the 4.6L and 5.4L by having a completely new cylinder head design with maximum flow into each cylinder and greatly reduced valvetrain friction and weight. Larger cylinder head bolts and high-end sealing technology help contain much higher 11.0:1 compression.
Because the Coyote development timeline was so tight, the team had to fast-track this engine through development, prototyping, testing, certifying, and into production. They didn’t have the traditional three-year development window to get this thing turning and burning. Existing Modular mule engines had to be used to test Coyote engine parts for durability. A lot of scrap went into the recycle bin that didn’t measure up.
To get the Coyote where Ford wanted it required a lot of back and forth between the hardware people in engine building and dyno rooms and the software geeks who compared information and made adjustments as necessary. It was a great combination of hard-core seat-of-the-pants engine experimentation and hightech computer design. Engines were tortured, thrashed, and trashed via hundreds of hours of dyno lab testing. Any weak links were revised or eliminated.
By January 2009, Coyote engine dyno testing was in full swing with the first prototype mule engines going under heavy loads and being throttled until they were worn out. Ford engineers disassembled used-up mules and inspected them. Much to their amazement, the Coyote held up very well with minimal abnormal wear issues.
Engine testing goes beyond hard full-throttle pulls on a dyno and in test vehicles. It must also pass corporate approval and federal emissions standards. Those first few prototype engines made it through testing and certification with very few changes. Field testing mule vehicles in extreme heat and cold was the final frontier where the Coyote proved its worth.
By the time the Coyote reached mass production in 2010, it had been tested, tortured, and abused unlike any Ford engine to date. To ascertain its integrity, it was put through greater extremes than any Ford engine ever had before. The team wanted an engine that would deliver fuel efficiency, durability, and longevity. They wanted an engine that could handle both the daily commute and the racetrack without complaint.
Unfortunately, a sticky matter was the timing of this project. The Coyote was conceived during one of the most trying financial times in modern automotive history. Staring potential bankruptcy in the eye, Ford CEO Alan Mulally saw the value in investing in product and people (without government assistance), and it paid off handsomely in a new generation of exciting vehicles and powertrains. Mustang was among the first car lines to witness the payoff.
The Coyote V-8 is an easy engine to understand and build because it is produced in only one North American plant (Essex, Ontario, Canada) with basically one block and head casting type, although I fully expect more variations in the future as this engine grows to meet demand. There isn’t the confusion of two engine plants with different approaches and parts as there is with the 4.6L and 5.4L engines.
The Coyote’s firing order is different than the 4.6L and 5.4L V-8s at 1-5-4-8-6-3-7-2. The compression ratio is reminiscent of the 1960s at 11.0:1, making the most of its lower displacement and carefully executed valve timing. Imagine being able to do this with 87-octane fuel (although 91-octane is preferable). This innovation comes from Ti-VCT, which enables each cam to adjust valve timing based on input from the powertrain control module (PCM).
Retooling for the 5.0L Ti-VCT was simple because it remained within the parameters of the Modular engine family. The Coyote block shares the same bore spacing (3.937 inches, or 100 mm), deck height (8.937 inches), bellhousing bolt pattern, and external dimensions as the 4.6L SOHC and DOHC engines. Bore size increased to 3.629 inches (92.2 mm) along with an increased stroke of 3.649 inches (92.8 mm); still a “square” engine design with identical bore and stroke. It is an entirely new block design with heavier webbing and other internal improvements intended to support greater power output from modest displacement.
The Ti-VCT engine employs a rugged aluminum block with thin iron cylinder liners. This means that the block must be sleeved with thicker liners for all-out racing with more than 1,500 hp. Modular Motorsports offers racers the Pro Mod Coyote block with extra-thick ductile-iron cylinder liners that stay put to ensure block integrity. You can build one of these for the street if you’re an avid weekend racer. Bores can be up to 3.700 inches to achieve 5.2L.
The block architecture holds this beast together. Main bearing webs are thicker and heavier, allowing for performance extremes from enthusiasts and Ford product planners. This means the Coyote block can stand up to naturally aspirated performance demands, supercharging, nitrous, direct injection, and more. This block can withstand more than 1,500 hp when sleeved with the thicker ductile-iron cylinder liners mentioned earlier.
With this new block come advances in crankcase ventilation known as “bay to bay” breathing. Ford engineers located venting in the main webs designed to allow the freedom of air scavenging without robbing power. The result is a more positive ring seal, which helps efficiency and power.
Gone is the Modular’s coolant tube down the middle of the valley. Instead, coolant is routed through the front of the block, which leaves plenty of room for exotic induction systems and superchargers.
The Coyote has an inductionhardened, fully counterweighted crankshaft that’s virtually indestructible, featuring an eight-hole flange. Team Coyote elected to stay with the 4.6L engine’s main and rod journal dimensions because they have been a proven success in nearly two decades of service in every application imaginable. What’s more, instead of it using tri-metal bearings, aluminum bearings were borrowed directly from the 4.6L engine.
The Coyote engine shares the same connecting rod dimensions with the 4.6L engine at 5.933 inches center to center although it is not the same rod. It is stronger with 12-point bolt heads. Rod ratio is 1.62:1. The Coyote’s 5.933-inch cracked rod is a sintered-metal I-beam component engineered for extreme street and weekend race duty. This rod does not stand up to the severe hammering of supercharging and nitrous. If you’re planning a supercharger or nitrous induction, Manley H-beams are a better choice. The stock rod can take a lot of punishment along with 7,000 rpm. However, it is pushing your luck to go with anything less than a heavy-duty forged steel I-beam or H-beam rod if you’re going to push it above 500 hp.
The Coyote has lightweight hypereutectic pistons with coated skirts for reduced friction and wear. Ford engineers weighed the benefits of forged versus hypereutectic; hypereutectic won because of its weight and expansion properties.
Forged pistons are loose and noisy when cold and that generated plenty of complaints with 4.6L and 5.4L engines. Hypereutectic pistons are quieter because you can run tighter tolerances without consequence.
The Coyote tolerates the extremes of street and weekend race duty and offers durability. However, you’re better off with a forged and coated piston for best results if you intend to supercharge or run nitrous.
Another reason Ford opted for a hypereutectic piston is the oil cooling jets that keep the pistons considerably cooler, which in turn improves piston life. This approach also allows for faster warm-up because oil is in direct contact with one of the hottest parts of the engine right from the start. It has been proven by Ford engineers that the crankshaft runs roughly 25 degrees F cooler with the oil jets. This enables the engine to operate on 87-octane fuel and survive (although 91-octane is optimum).
It’s very important to consider potential clearance issues. Heavy-duty I-beam and H-beam connecting rods may or may not clear the tight confines of the Coyote block. You must first do a mock-up and make sure everything clears by at least .060 to .100 inch throughout 360 degrees of crank rotation with all rods and pistons (without rings) installed. Pay close attention to piston skirt-to-crank counterweight clearances, which can be very tight and the reason the Coyote doesn’t accept any more than a 3.649-inch (92.5 mm) stroke.
Cylinder Head and Valvetrain
The real news about Ford’s Coyote is a revolutionary new cylinder head design that makes the engine less bulky while providing extraordinary breathing. The Coyote’s intake ports are free from restriction, outflowing even some of the most legendary racing cylinder heads. Intake flow numbers are in excess of 300 cfm. Because the Coyote’s top end was designed more as a package than simply individual components, it produces numbers never before seen in a factory Mustang engine. These numbers exist without special port work, which leaves the door wide open for port work and even more power.
Engineers chose to really focus on aspects of port design. This included the distance between the four valves, valve angle, valveseat revisions, and more. Valve angle had to change to improve valve-to-piston clearance and airflow. Thanks to advanced computer technology, engineers were able to come up with a new cylinder head quickly. It only took around-the-clock development work for six months to get it done.
When Team Coyote was finished with basic cylinder head casting development, they had to go back and look at cam profile and the size and weight of valvetrain components. Think of high-revving motorcycle engines; this is what Ford was faced with during development of the Coyote. Rocker arms and valvesprings had to be smaller to improve both efficiency and performance. There had to be less reciprocating weight to enable high revs. Put the 4.6L and 5.0L rocker arms and valvesprings side by side and you see the difference in size. The 5.0L engine does it with less mass and weight. Even more, it enabled Ford to reduce cylinder head size and width, which reduced overall engine width.
The Coyote’s valvetrain system is the most complex cam and valvetrain package ever installed in a Mustang and it is designed to optimize all driving conditions. “Ti-VCT” means that intake and exhaust cams work independent of each other based on driving demands. Each camshaft is indexed or phased around its centerline by oil pressure. Oil pressure is metered electronically via solenoids and phasers to control cam indexing as required.
Ti-VCT enables the Coyote to deliver an incredibly wide power band across RPM ranges while providing the bonus of high-end horsepower, which was never easy to achieve before. What makes the Coyote’s Ti-VCT different from the rest of the Ford line is cam torque actuation, which uses valvespring energy to advance and retard timing more quickly depending on engine RPM and driving demands. Instead of a complex electronically controlled shuttle valve and oiling system routing, the Coyote’s Ti-VCT is a simple on/off solenoid that lets cam torque do the rest.
Ti-VCT can advance/retard valve timing by as much as 50 degrees and do it in 0.2 second. This approach offers you modest valve timing on the way to work and more aggressive valve timing when it’s time to test performance limits. For the environmentally conscious, the Coyote doesn’t need EGR because valve overlap is increased in certain types of driving, especially deceleration, which reduces hydrocarbon emissions.
To do the complex work of Ti-VCT and other critical functions, Ford’s EEC was asked to do more than in previous applications. It is known as the Copperhead system, a new multi-channel system designed to control every aspect of engine and driveline, including Ti-VCT. Instead of a simple on/off system of cam modulation, Ti-VCT advances and retards valve timing on each cam. Electronic controls monitor and control oil pressure to the cam phasers.
You don’t need to worry about maintaining or tuning Ti-VCT. It is a “life of the engine” system. If the cam phasers fail, they’re easily replaced by removing the cam cover, aligning timing marks, and replacing the phasers. The thing that makes the Coyote’s phaser function different than the 3V Modular’s is the cam position sensor location. It’s at the opposite end of the cam on the Coyote.
The Coyote’s induction system is a composite design, which is mainstream today because it is both lighter and a great heat insulator. It stays cool and keeps the intake charge cooler. It is also easier to manufacture.
Induction design and tuning has changed considerably thanks to computer-aided design. The Coyote’s intake manifold, also known as a plenum, is a single-plane design with long intake runners for a broad torque curve. These are 16.9-inch (430-mm) runners with gentle turns for improved flow. They are scrolled deep into the valley to allow for a lower hoodline.
Because Ford has eliminated the coolant tube in the Modular valley, there’s more room for induction. The 80-mm throttle body is centered on top at the front of the engine. Another great evolution is a digital mass air sensor for extremes of fine-tuning as you drive.
The Coyote continues with traditional port injection because Ford engineers felt it didn’t need direct injection. The Coyote’s cylinder head castings have a provision for direct injection. Ford just isn’t there yet.
The Coyote’s exhaust system is just as crucial to power and efficiency as the rest of the package. Although headers might not seem like a big deal in the big performance picture, they’re important and were a great area of focus for Team Coyote. The Coyote has shorty tri-Y headers that were painstakingly thought out and executed. The engineers had to fight for them. Bean counters didn’t want them because they’re twice as costly to produce as cast-iron exhaust manifolds. However, they are crucial to emissions, power, and fuel economy.
The Coyote’s factory shorty header has enabled the Ti-VCT to produce some 400 ft-lbs of torque. Try that with your 5.0L pushrod small-block.
Lubrication and Cooling
The Ti-VCT Coyote was born to rev high, and with that dynamic comes huge oiling system demands. It must sustain lubrication to 7,000 rpm and beyond and under extreme driving conditions. Ford opted for an 8-quart oil pan and a windage tray/ pan gasket combination. This is good for keeping oil pressure and volume on target. It also created the huge challenge of oil drain-back because oil arrives in abundance. Ford solved this problem, and others, with crankcase breathing chimneys. These PCV chimneys improve both drain-back and crankcase ventilation.
Close attention was paid to the Coyote’s cooling system, which focuses on exhaust valve cooling and other extremely hot areas of the engine. Ford calls this cross-flow cooling; it is different than conventional cooling employed by the 4.6L and 5.4L Modulars.
Cross-flow cooling routes coolant up through the block where it enters the 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. Gone is the mid-valley coolant tube that consumes so much space in the 4.6L and 5.4L engines.
Written by George Reid and Posted with Permission of CarTechBooks