Ford has barely granted adequate time for its updated 2010 Mustang to shine in its own model year before launching a new 2011 model this spring.Model-year tomfoolery aside, the latest Mustang GT signals the return of the “5.0” badge. And nitpickers and Mercedes-Benz AMG “6.3” owners both should take note: This time it’s a legitimate 5.0 liters under the hood, rounded up from 4951 cubic centimeters, unlike the old Windsor V-8 (used intermittently from 1968 to 1995), which was in fact a 4.9-liter (4942cc) engine. More importantly, the output figures of 412 horsepower and 390 pound-feet of torque represent gains of 97 and 65, respectively, versus the 2010 model, enough to instantly erase the power deficit that the GT formerly ceded to its resurrected rivals, the 426-hp Chevrolet Camaro SS and the Dodge Challenger (in both 376-hp R/T and 425-hp SRT8 trim).
Ford heaped a lot of attention on the base Mustang, too, which at long last has ditched its ancient iron-block, 4.0-liter V-6 for a new version of Ford’s thoroughly modern DOHC, 3.7-liter V-6. With 305 horsepower, only 10 less than last year’s GT, this more affordable Mustang is no longer a car for poseurs and tanning-salon employees.
But back to the GT engine, which is officially labeled the 5.0-liter Ti-VCT DOHC V-8, though we prefer its unofficial code name, Coyote. It’s all-new, if you don’t count the bore-center spacing shared with the “modular” 4.6-liter V-8 that powers the 2010 Mustang GT. The reason for that is twofold: It allowed Ford to use its existing manufacturing infrastructure, and it made it easier to stick to a compressed development timeline. Early alternatives—a variant of the forthcoming 6.2-liter truck engine and even the 5.0-liter Jaguar V-8—were considered before Ford chose the Coyote in May 2007. To meet the production deadline of January, Mike Harrison, the V-8 program manager, had to cut 12 months from the normal development schedule, which meant eliminating an entire prototype phase.
Aside from a few common nuts and bolts, nothing from the 4.6-liter carries over to the new 5.0. The larger displacement was achieved by increasing bore and stroke to 92.2 by 92.7 millimeters, up from 90.2 by 90.0mm. The compression ratio has leaped to 11.0:1, from 9.8. Most of the design work on the Coyote focused on airflow. It was such a priority that cylinder heads from the Shelby GT500 that might have been used were rejected because they didn’t flow well enough. The Coyote design moves the intake camshafts as far to the outside of the vee as possible to make room for a straight, smooth passage from the intake manifold. The intake valve’s diameter has been increased by 3.2mm, and a second exhaust valve was added, so there are now four valves per cylinder.
Plus, there is variable valve timing on both the intake- and exhaust-valve cams. Ford uses a cam-torque-actuated system, and each of the cam adjusters, located within the cam sprocket, has three lobes surrounded by oil. Solenoids control the flow of oil into the adjusters, and the size of the oil pocket on either side of each lobe is pumped up or reduced by using the energy from the natural fluctuations in cam torque as the valves open and close. This makes the cams move relative to the motion from the timing chain. Compared with systems where oil pressure is the motive force, Ford says this arrangement is faster and more efficient, and it doesn’t require a bigger pump.
The output of 412 horsepower at 6500 rpm and 390 pound-feet of torque at 4250 rpm (that’s with premium fuel; regular unleaded drops the figures to 402 horses and 377 pound-feet) is slightly less than the 426 horsepower in the Camaro SS and the Challenger SRT8’s 425. The Mustang GT wins in specific output, though, at 83 horsepower per liter compared with 64 and 70 horses per liter for the Chevy and the Dodge, respectively. The higher-tech and more expensive V-8 in the Lexus IS F manages only one better than the Coyote on this scale. And we remind you that the last Mustang GT we tested was 300 pounds lighter than the Camaro SS. Ford claims the new engine is only about 15 pounds heavier than the 4.6, so the GT’s power-to-weight ratio should be best in class.
Should the need for more power arise, Ford has future-proofed the Coyote engine for applications such as supercharging and direct injection. There are four-bolt mains with side bolts through the block, and the bolt sizes have been increased one millimeter here as well as on the cylinder head. The main-bearing bulkhead width increases two millimeters.
As with the V-8, attention to the V-6 engine focuses on airflow. This is essentially the same 3.7-liter found in the Lincoln MKS and MKT, with a few key changes. A redesigned cylinder head increases compression to 10.5:1, from 10.3. Variable valve timing, which is now on the exhaust valves, uses the cam-torque system as in the V-8, and intake-valve lift is increased. A new exhaust manifold completes the list of airflow improvements. To adapt the engine to a rear-wheel-drive layout, Ford engineers had to design a tube molded into the lower intake that moves the coolant plumbing from the thermostat housing at the rear of the engine to a new water-pump location up front.
The result is 305 horsepower at 6500 rpm and 280 pound-feet of torque at 4250 rpm (when using regular unleaded)—30 more horsepower than the premium-fuel number for the MKS. More importantly, it’s a jump of 95 horsepower and 40 pound-feet from the old 4.0-liter, with fuel-efficiency increases to boot. Ford predicts ratings of 18 to 19 mpg city and 29 to 30 mpg highway, depending on transmission choice, up from 16 to 18 city and 24 to 26 highway.
