Ford Modular V8 Engine

Ford Modular V8 Engine

FORD MODULAR V8 ENGINE FAMILY ORIGINS
By the mid-80s, Ford made a priority of designing a totally modern engine family to replace its aging OHV V8s. They designed it such that the fundamental dimensions of the engine were common across an entire family of engines, sharing many common parts, all set up in a ‘modular’ format, allowing parts to be mixed and matched to created engines of various displacements and outputs. This, and the way the engine factory in Romeo, Michigan was set up to quickly change out tooling so that different engines could be built on the same line, gave the new engine family it’s name: The Ford Modular V8. Early on, they were also referred to as “Romeo V8s” because of where they were built. Since then, they have also been produced in Windsor, Ontario Canada. Ford Modular V8s come in a wide variety of displacements (4.6L, 5.0L, 5.2L, 5.4L and 5.8L) and configurations (SOHC 2-valves/cylinder; SOHC 3-valves/cylinder, DOHC 4 valves/cylinder, normally-aspirated or supercharged, cast iron block or aluminum. The bore centers of Ford Modular V8 engines is 100mm. Despite a large displacement deficit, and a lower horsepower number on paper, the first Modular, the 4.6L 2-valve engine was able to carry the 1991 Lincoln Town Car (the car in which it debuted) to 60 mph quicker than the old OHV 5.0 and with substantially better fuel economy and cleaner emissions. Mission accomplished.

FORD MODULAR V8s ARE SQUARE
The terms “Undersquare”, “Square” and “Oversquare” refer to the ratio of an engine’s bore to its stroke. If the bore (piston diameter) is greater than the length of its stroke, then it is Oversquare. Square would be an engine where its bore and stroke were equal. An Undersquare engine would have a stroke that is greater than the bore. Early engines were generally undersquare, very undersquare. After World War II as modern OHV V8s replaced ancient flatheads, they were Oversquare, it was considered the ‘modern’ thing to do. Undersquare engines are generally torquey with gobs of low-end pulling power, but an unwillingness to wind. Oversquare engines rev more freely and produce bigger power higher in the rpm-range, but don’t have as much stump-pulling power just above an idle. In theory, Square engines combine these strengths. The OHV 5.0 V8 was very Oversquare with a 4-inch bore and a 3-inch stroke. The 4.6L was nearly Square at 90.2mm X 90.0mm. The Coyote 5.0 is just barely Undersquare at 92.2mm X 92.7mm. The 5.4 is solidly Undersquare at 90.2mm X 105.8mm. That’s a bore of 3.552 inches by a stroke of 4.165 inches, almost the opposite of the old pushrod 5.0s 4.00″ X 3.00″ bore-and-stroke. The 5.8L:engine grew in bore diameter to 93.5mm with the 105.8mm stroke remaining unchanged from the 5.4, so it’s actually a little less Undersquare, but still very Undersquare nonetheless. Where is Ford going with this? Certainly not in the same direction as most of the rest of the auto industry. But when has Ford ever done that? Obviously they’re onto something, as you will see from the data below. In fact, as you will see below, the torque figures are generally very close to the horsepower figures, which is not what you’d expect from an undersquare engine. Normally, the torque number is significantly higher, even with oversquare V8s, but undersquare engines should make even more low-end torque. We don’t see that here. So who knows? The Ford Modular Engine is here to stay, at least for the foreseeable future, in all its glorious forms, and probably some new ones we haven’t heard of yet.

4.6-Liter Ford Modular V8 Engine

ABOVE: Under all that plumbing is a 4.6L 3-valve Modular V8 from a 2005 Mustang GT, making 300 hp and 320 lb/ft of torque.

4.6-LITER MODULAR V8
The first Ford Modular V8 was a SOHC (Single Overhead Cam) 4.6-Liter V8 with 2 valves-per-cylinder, and introduced in the 1991 Lincoln Town Car, making just 210 horsepower, less than the 5.0 OHV V8 it replaced. It first landed in a Mustang (GT) in 1996, still making just 215 hp. It took until 1999 to hit 260 hp and 302 lb/ft of torque. When the retro-styled 5th-gen Mustang came out in 2005, the GT had a new version of the 4.6L V8 with 3 valves-per-cylinder and making 300 hp. From there, things quickly got out of hand.

ABOVE: A DOHC 4-valve 4.6L V8 from a 2001 Mustang SVT Cobra with 320 hp.

5.0-Liter Coyote Ford Modular V8 Engine

FORD MODULAR V8 CONSTANTLY IMPROVED
The first DOHC (Dual Overhead Cam) 4-valve-per-cylinder (32 valves total) Modular V8 came in the 1993 Lincoln Mark VIII, with 280 hp, naming it “In Tech” in 1995. Horsepower and torque rose slowly but steadily over the years, with normally-aspirated 4.6s topping out at 320 hp in the 1999-2001 Mustang SVT Cobra. For the 2003 SVT Cobras Ford dropped a supercharger onto the DOHC 32-valve engine to produce 390 horses and 390 pound-feet of torque. Ford also sold this engine to many boutique builders of exotic cars, who often did their own tuning. The 2004-2006 Koenigsegg CRR hypercar ran a supercharged 4.6 32-valver making 806 horsepower.

THE COYOTE 5.0
The 5.0-liter “Coyote” V8 is the latest evolution in the Ford Modular V8 engine family. By the late 2000s, Ford knew they needed a stronger engine than the 4.6 to compete with Chevy’s 6.2L LS3 in the Camaro, and Chrysler’s new 6.4L Hemi in the Challenger and Charger. The new engine had to share outer dimensions with the old engine, along with bore centers, deck height, and bell housing bolt pattern so that it would drop right in to the same slot, and could be produced with the same tooling. Introduced in the 2011 Mustang GT, the new Coyote motor made 412 hp, creeping up to 423 hp over the next few years. The 2012-2013 Mustang Boss 302 had the ‘road runner’ version, good for 444 hp. In 2000 Ford enlarged the 5.0 Coyote to 5.4 liters for the Mustang SVT Cobra R, the Shelby GT500 and the Ford GT supercar.

5.2-Liter “Voodoo” V8

5.2-LITER “VOODOO” ENGINE
The Voodoo is based on the 5.0 Coyote, enlarged to 5163cc (315 cid), and featuring a flat plane (180-degree) crankshaft. Nearly all V8 cranks have their rod journals offset by 90-degrees of rotation. One of the few exceptions has been Ferrari, whose flat-plane V8s are known for their high-RPM wail. While ideal for making big power in small V8s, 5.0 liters of displacement has always been considered the practical limit of flat-plane cranks, due to vibration problems. But somehow Ford has found a way to quell the vibes on the 5.2-liter Voodoo V8 all the way to its 8250-RPM redline. With a 12.0:1 compression ratio, the normally-aspirated Voodoo makes 526 hp, and was designed specifically for the 6th-gen Ford Shelby GT350.

5.8-Liter “Trinity” Ford Modular V8

ABOVE: This supercharged 5.8L Trinity motor made 500 hp in the 2007 Shelby GT500.

SUPERCHARGED FORD MODULAR V8s
When it comes to horsepower, too much is never enough. In 2007, Ford started dropping superchargers on Coyote V8s with predictable results. The 2007 Shelby GT 500 earned its name with 500 horsepower from its force-fed Coyote. Power steadily rose in successive GT500s, reaching 550 hp by 2011. The Ford GT mid-engine supercar used the same 550 hp engine, now with an aluminum block.

5.8-LITER “TRINITY” ENGINE
Ford bored and stroked the Coyote out to 5.8 liters (355 cid), reworked cylinder heads, Ford GT cams, piston cooling jets, 5-layer MLS head gaskets, and an over-rev function that allowed a 7,000-RPM redline for up to 8 seconds (normal redline is 6,250 rpm). It had a 9.0:1 compression ratio supplied by a 2.3-liter TVS supercharger with up to 14 psi of boost. The Trinity has two 37mm intake valves and two 32mm exhaust valves per cylinder, an aluminum block and heads, and produces 662 hp and 631 lb/ft of torque. It launched in the 2013 Shelby GT500.

6.8-LITER V10 TRUCK ENGINE
The Ford Modular Engine Family doesn’t just include V8s. Being modular in concept and design, 2 more cylinders were added to the V8, with the same bore and stroke as the 5.4L Coyote V8, but as a V10 has a displacement of 6760cc (413 cid). The SOHC V10 is a truck engine, and not the focus of this study. We’re all about muscle cars.

SPECIAL THANKS
Our thanks go out to Specialty Sales for some of the photos on this page. They are a classic car dealership with 4 locations in the San Francisco Bay Area and hundreds of cars. Visit their website at www.SpecialtySales.com

Keyword: Ford Modular V8 Engine