What happens when a legend from Texas reunites with a legend from Dearborn? The most powerful Mustang ever.
After 40 years, racing legend Carroll Shelby and the Ford Mustang are back together with the introduction of the 2007 Ford Mustang Shelby GT500.
The collaboration between Shelby and Ford's Special Vehicle Team (SVT) is yielding an instant collector's Mustang that builds 500 horsepower in its 5.4-liter supercharged V-8.
A modern interpretation of the Shelby Mustang of the 1960s, the Ford Shelby GT500 uses advanced engineering to attain the performance that made the original GT500 the king of the road.
True to the original GT500, it will be available both as a coupe and as a convertible when it goes on sale in the summer of 2006.
"When Carroll was developing the original GT350 and GT500, he wanted to build the most powerful, most capable Mustangs of his day," says Hau Thai-Tang, director, Advanced Product Creation and Special Vehicle Team. "Our goal was to build the most powerful, most capable Mustang ever."
Serving as touchstone and inspirational leader for both the concept and the production versions, Shelby was impressed by what the team has accomplished.
"It's one thing to put 450 horsepower in an exotic supercar," says Shelby. "It's another to put that much power in something as affordable as a Mustang. The fact that they not only met their goal but pushed on to 500 horsepower is a remarkable achievement."
Shelby knows something about creating modern supercars. He served as a senior adviser on the team that developed and built the 550-horsepower Ford GT.
As expected of anything with Shelby's name on it, the heart of the car is what's under the hood. The Ford Shelby GT500's supercharged 5.4-liter, 32-valve V-8 evolves from Ford's experience with tuning its modular, or MOD, engines. Output is a brawny 500 horsepower.
The engine is force-fed an air-and-fuel mixture via a "Roots-type" supercharger providing 8.5 pounds per square inch of boost. The GT500 uses a cast-iron engine block. It borrows from the Ford GT program aluminum, four-valve cylinder heads, piston rings and bearings, adding a high level of performance durability to the drivetrain. "Powered by SVT" camshaft covers add the finishing touch to the engine.
Helping put the power to the pavement is a 6-speed manual gearbox. For the performance driver, its evenly spaced gears mean less "stirring" is needed to find the "sweet spot." This gives a rewarding experience throughout the engine's broad torque curve. The heavy-duty transmission has proven itself a willing companion to Mustangs in both road and track environments, including recent road-going Mustang Cobras and the new race-winning Mustang FR500C.
Power Requires Control
The Ford Mustang Shelby GT500 continues a legacy of all-around performance that made the original a world-class racer on tracks and road courses around the world.
The Ford Shelby GT500 starts with the solid Mustang underpinnings. The all-new Mustang was designed from the beginning with performance derivatives in mind, providing an exceptionally rigid, well-engineered starting point for GT500 chassis engineers.
SVT engineers retuned and upgraded key chassis components. Improvements such as revised shocks, spring rates and upgraded stabilizer bars help the Ford Shelby GT500 stop and turn with the same authority as it goes.
The Ford Shelby GT500 features a MacPherson strut independent front suspension with Reverse L lower control arms, and a solid-axle, three-link rear suspension with coil springs and a Panhard rod for precise control of the rear axle.
This rear suspension design has been validated on the track by Ford Racing. The Ford Racing Mustang FR500C was purpose-built from the base 2005 Mustang body structure and suspension geometry to run in the Grand-Am Cup series, a class of road racing for production-based cars.
Competing against the best from Germany and Japan, a Mustang FR500C won its first race in the season opener at Daytona International Speedway in February 2005. It went on to dominate the season and clinch the championship.
"SVT and Ford Racing will be working closer than ever as we go forward on future projects, especially Mustangs," says Thai-Tang, a Ford Racing alumnus who served as the race engineer for the Newman-Haas Racing team in 1993.
To match this power and handling ability, engineers fitted some of the biggest brakes in the business to the Ford Shelby GT500. Four-piston Brembo calipers are fitted to 14-inch Brembo vented rotors up front, and 11.8-inch vented discs in the rear continue SVT's legacy of great-braking Mustangs. Secure footing is provided by 255/45ZR high-performance tires in front and 285/40ZR high-performance tires in back. Wheels are 18 inches by 9.5 inches.
The Snake is Back
One glance shows this is not the typical Mustang Cobra. A sinister-looking front-end design includes wide upper and lower fascia openings with a functional air splitter. The upper intake sports the famous Cobra logo floating off-center in place of a centered galloping pony found on other Mustangs. On either side, slanting headlamp openings add to the dramatic front appearance.
The bulging hood has heat extractors protruding near the leading edge, combining to provide improved airflow and aerodynamics. As air passes over the hood, hot air from the engine compartment is drawn out through ducts attached to the hood extractors.
"The restrained, performance-oriented SVT design theme has become instantly recognizable to enthusiasts without brash styling cues," says Doug Gaffka, design director, Ford SVT vehicles. "The GT500 takes a huge leap forward by combining the modern Mustang muscle car with the classic Shelby performance look."
The 2005 Mustang design team drew inspiration from classic 1968 Mustangs, the models that transformed the mild-mannered pony car into a muscle car with attitude. Envisioning a high-performance model, the team tested GT500 design cues on the Mustang GT coupe concept that was unveiled at the 2003 North American International Auto Show.
In 2004, designers further developed the GT500 look on the Mustang GT-R, a race-bred concept with the dual purpose of foreshadowing SVT's Mustang design direction and Ford Racing's plans to return Mustang to road racing. The Ford Shelby GT500 Cobra concept coupe capped the design conceptualization effort.
The production Ford Shelby GT500 Coupe now comes into full light, punctuated by the classic Le Mans-style white stripes that race along the top from nose to tail. The stripes recall the Shelby Mustangs that marked another important 1960s Mustang transition when Ford put it on the track to becoming a racing legend. The GT500 nomenclature is prominent in the lower bodyside racing stripe, another cue from the classic Shelby Mustangs.
In a touch also borrowed from the GT500's past, no Le Mans stripes will be seen on the 2007 Ford Shelby GT500 Convertible. However, the convertible will sport a cloth top similar to those found on pricier convertibles.
"There were no Le Mans stripes on Shelby's original GT500 Convertible, so we decided to pay homage by not offering them on the 2007 Ford Shelby GT500," says Gaffka. "We also went with a cloth top material as another measure of substance and authenticity. The fabric used is the same used on the 2002-03 SVT Mustang Cobra, the Thunderbird, Jaguar and Ford's other high-end convertibles."
The unique rear fascia features lower strakes inspired by the Ford GT's integrated rear airflow diffuser, and a rear spoiler reminiscent of a classic GT500. To mark the collaboration of two Mustang performance icons, the GT500 features Shelby and SVT badging.
The fenders each feature an updated design of the Cobra. The front grille features an off-center snake in place of the standard running horse. "GT500" is emblazoned inside the side rocker stripes, and the name SHELBY is prominently written across the rear deck. The SVT logo can be seen on the wheel center caps, a signature SVT location, as well as on the doorsill plates. To top it off, the medallion between the taillights reads "Shelby GT500" centered on the Cobra image.
Inside, too, upgraded levels of flair and function abound. The locations of the speedometer and the tachometer are swapped to provide performance-oriented drivers with a better view of shift points while changing gears. Front seats have received additional lateral support to help keep the driver optimally positioned during cornering. The interior is offered in a choice of two colors, Charcoal Black or Charcoal Black and Crimson Red. The charcoal/red offering features Crimson Red seating surfaces and door panel inserts. Seating surfaces are leather with both interior treatments. Snake logos embossed in the seat backs finish the package.
The Shelby GT500 script and Cobra image are repeated on the steering wheel cap. Behind the wheel, the gauges wear light faces in keeping with SVT tradition. The chromed accessories inside the cabin have been replaced with a satin aluminum finish, including the aluminum shift lever knob that is nicely positioned for quick, positive shifts.
SVT and Shelby: The Legends Grow
With the look and legend one would expect from Shelby and the kind of power and performance enthusiasts have come to expect from SVT, the GT500 points to a brand-new era in Ford's performance future.
Shelby first put his name on a Mustang back in 1964 when he was asked to inject some high performance into the brand-new pony car. The result was the GT-350R, a lightweight, handling-focused race car that earned Mustang its first performance credentials. Subsequent Shelby Mustangs included a street version of the race car, the GT-350, and what was known as the "rent-a-racer" Mustang, the GT-350H, a joint project with the Hertz rental car corporation.
The ultimate Shelby Mustang of the era was the GT-500KR, or "King of the Road." Powered by a big block 428-cubic-inch "Cobra Jet" V-8, the GT-500 was one of the most powerful, and memorable, muscle cars of that period. Shelby Mustang production ceased in 1970 with a total volume of 14,559 units.
The Ford Special Vehicle Team brought high performance back to Mustang in 1993. After 12 years, with nearly 80,000 high-performance Mustangs on the streets and total SVT vehicle production nearing 145,000, SVT is primed for growth with the GT500 serving as the foundation for other performance Mustang projects.
By bringing together Shelby and Ford SVT, the company's commitment to performance becomes as powerful as at any time in its history - including the famed "Total Performance" days of the 1960s. From the Ford GT supercar, the GT500, to a rejuvenated Ford Racing Performance Parts program, performance and racing can drive innovation and add luster to Ford's proud brand heritage.
"SVT will remain the leader in performance vehicle engineering," says Thai-Tang. "It will continue to build new, innovative products using advanced processes that will not only provide great enjoyment to the dedicated driving enthusiast, but that also will provide great benefit to other Ford products and Ford Motor Company itself."
The 2007 Ford Mustang Shelby GT500 is a purposeful performance car and striking to look at.
The design team did not merely take heritage cues and paste them onto the contemporary Mustang. Working with the engineering team, they dedicated themselves to a design that would enhance the car's performance.
For example, the fog lamps were removed from the upper grille opening where they are located on the Mustang GT. Smaller units were relocated on the outside of the lower front fascia where they function well.
"We found that the original Shelby Mustang's design came about in response to maximizing the car's performance," says Doug Gaffka, chief designer for Mustang, SVT and Vehicle Personalization. "The same is true of the SVT design language that has evolved over time."
A further example of how form follows function is the design of the heat extractors on the hood of the Shelby GT500. Here, they can better remove heat from the engine compartment - an important consideration for a car generating 500 horsepower.
"It is perfect, says Carroll Shelby of the car's overall design. "I wouldn't change a thing. It is everything I expected a modern Shelby Mustang to be."
Other functional aero additions to the Shelby GT500 can be found at the front and rear. The rear spoiler adds significant downforce. Similarly, the front air splitter effectively combats lift.
The 18 x 9.5-inch wheels worn by the Shelby GT500 also bear a resemblance to those of the Ford GT.
Upscale Convertible, Regalia Stripes
The Shelby GT500 convertible shares cues with other high-end Ford Motor Company products. Rather than using vinyl for its top, as the mainstream Mustang does, the GT500 convertible uses the same type of cloth as that on the Ford Thunderbird and the Jaguar XK. The top is available only in black to match the car's predominantly black interior.
"There is definitely an upscale feel to the top," says Keith Rogman, SVT design manager. "It fits in the same category as the stripes: They don't make the car go faster, they don't make it split the wind better, but they add a certain intangible authenticity to the car that you can't quantify."
Indeed, stripes don't make the car go faster, but they play a big role in the car's identity. In coupe form, the car wears the full regalia of stripes Carroll Shelby bestowed upon the original GT500 coupe: a Le Mans stripe that runs over the hood, roof and rear deck and side stripes bearing the legend "GT500" nomenclature.
As did the original GT500 convertible, the modern version carries the side stripes but foregoes the Le Mans stripe. The Le Mans stripe, the side stripes or both may be deleted from the Coupe. The side stripes are also a delete option on the Convertible.
The stripes come in a range of four colors (Performance White, Vista Blue, Tungsten and Satin Silver) that, with one exception, can be matched with at least three of the seven available exterior colors. The exception is Vista Blue, which can be paired only with a Performance White exterior.
Exterior colors include Torch Red Clearcoat (which can be paired with Performance White or Satin Silver stripes), Alloy Clearcoat Metallic (Satin Silver or Tungsten), Vista Blue Clearcoat (Performance White or Tungsten), Performance White Clearcoat (available with Vista Blue or Tungsten stripes), Tungsten Grey Clearcoat (Satin Silver), Grabber Orange (Performance White or Tungsten) and Ebony Clearcoat (Performance White or Tungsten stripes).
"Except for the Grabber Orange and Tungsten combination, these combinations echo what we did with the original car," says Shelby.
Peter Horbury, executive director, Design, North America, had the opportunity to learn firsthand just how much that color combination does catch the eye. "I sneaked out on the Woodward Dream Cruise in a yellow prototype of the GT500," he said. "Everybody knew what it was. People were stepping out in the road to take pictures."
Carroll Shelby, it seems, is not the only one who feels expectations have been met.
The 2007 Ford Shelby GT500 boasts an upgraded version of the mainstream Mustang's interior, designed to cater to the dedicated driving enthusiast.
Most apparent is the use of light-faced gauges, a tradition on SVT's cars and trucks and one that can improve readability under a variety of lighting conditions. The gauges also boast SVT graphics.
An astute observer will note that the speedometer and tachometer do not occupy the same positions they do in the rest of the Mustang line. In the Shelby GT500, the speedometer is on the left while the tachometer is on the right.
"This is something the SVT engineering staff insisted on - particularly because the GT500 is available only with a manual transmission," says Keith Rogman, SVT design manager. "Making the switch allows the driver the best view of the tach while changing gears."
Shelby GT500 sports a brushed aluminum finish on instrument trim, rings and door handles. This helps reduce glare and provide a bit of sparkle.
Adds Doug Gaffka, chief designer for Mustang, SVT and Vehicle Personalization: "This is very much in keeping with the SVT hallmark of substance. It gives the customer a direct benefit and not just a bit of decoration."
Sit Down and Drive
Substance and function also are the reason the front seats in the Shelby GT500 are different from other Mustangs. Bolstering has been added to provide increased lateral support. This helps keep the driver optimally placed.
Seating surfaces are leather, and the classic figure of a cobra is embossed on the front seat backs. The steering wheel rim is wrapped in leather and has unique thumb pads. The shift boot is also made of leather and the parking brake handle is leather clad.
Two interior color treatments are available, Charcoal Black and Charcoal Black with Crimson Red seat inserts and door trim panels. A GT500 Performance Interior Trim Package is optional. It features a leather-wrapped and stitched instrument panel brow and center console, upgraded door armrests and aluminum pedal covers.
Performance Sound System
SIRIUS Satellite Radio may be ordered with either the standard Shaker 500 Audio System or the optional Shaker 1000 system. The Shaker 1000 Audio System amps up to a full 1,000 watts from the standard system's 500. It includes two subwoofers as part of its 10-speaker array, and an audio input jack is standard. Both the Shaker 1000 and the 8-speaker Shaker 500 systems include AM/FM Stereo with a six-disc in-dash CD changer with MP3 capability.
Comfort and convenience touches abound. Manual air conditioning, power windows and power locks are standard. The center console includes not just an armrest, but storage as well. The interior also features dual power points as well as two cupholders.
And the Ford Special Vehicle Team has put its stamp on things as it welcomes enthusiasts into the car via bright door sill trim plates bearing SVT script.
A major goal set for the Shelby GT500 was to raise the handling to a new level. An easy road to success would have been to simply let Ford Special Vehicle Team chassis engineers tweak the critically acclaimed Mustang GT and have motorsports legend Carroll Shelby put his stamp on it. Easy. Right?
"It all depends on what you're satisfied with," says Tom Chapman, SVT Vehicle Dynamics Supervisor. "If you just want to make the Mustang live a bit more happily with a 60-percent increase in engine output, it's fairly simple to do. If you want it to equal the handling of the Mustang GT despite a larger displacement engine, that takes a bit more work.
"But if you want to hold it up to a whole new set of standards and be worthy of the Shelby GT500 name, then you better be prepared to roll up your sleeves."
The GT500 retains the Mustang's suspension setup. In the front, there are coil-over MacPherson struts with reverse "L" lower control arms made of lightweight I-section steel. In the rear, there's a three-link live axle with coil springs, Panhard rod, outboard shocks and stabilizer bar.
Because of its larger engine, the Shelby GT500 coupe has more weight over the front wheels than does the standard Mustang GT coupe. On the GT500, 57 percent of the weight is in the front and 43 percent is in the back. In comparison, on the Mustang GT 56 percent of the weight is in the front and 44 percent is in the back. Weight distribution of GT500 convertible matches the Mustang GT coupe due to the power-top mechanism behind the passenger compartment.
While a heavier nose generally disposes a car to understeer or "push," the Special Vehicle Team's engineers were able to retain neutral handling with the Shelby GT500 through the use of stiffer stabilizer bars. In addition, the rear bar of the GT500 is larger than that of the Mustang GT.
The GT500 uses a 34-millimeter tubular front stabilizer bar. Coupe versions of the GT500 sport a 24-millimeter rear bar, while convertibles come with a 20-millimeter bar.
"Stiffer stabilizer bars provide reduced roll and deliver a more aggressive handling balance," says SVT Vehicle Dynamics Engineer Dean Martin. "We've also given the GT500 higher spring rates at both ends to handle the greater mass of the car and also to reduce roll."
The Shelby GT500 sports Brembo front brakes with four-piston calipers and vented 14-inch discs. In the back, GT500 carries over the Mustang GT's 11.8-inch vented single-piston caliper rear-disc setup with unique pad material.
"We choose a friction material that will provide good track-day performance for the customer and still deliver satisfactory parking-brake performance and quiet operation," says Chapman.
Tires Manage Balance of Power
The GT500 sits on four 18-inch x 9.5-inch wheels, wearing 255/45ZR18 tires on the front and larger 285/40ZR18 tires on the rear.
"Larger rears help get the engine's immense power to the ground better when accelerating off the line," says Martin. "They also improve handling balance when you're powering away from the apex of a turn on the race track using as much torque and horsepower as the GT500 has."
Putting a Fine Edge on the Steering
The 2007 Ford Mustang Shelby GT500 adds a brace that connects the rear lower arm bushings side to side. This was added to improve durability and steering feel.
A unique steering pump is used and the steering gear utilizes a unique torsion bar. Again, these work to improve steering feel and precision.
"We wanted to make sure the changes we made met enthusiast customer demands," Chapman says. "So we took our engineering cars not only to the test track, but to real-world drive routes and race tracks to make doubly sure that the GT500 would live up to the expectations."
SVT tested the 2007 Shelby GT500 at Grattan and GingerMan in Michigan, Nelson Ledges in Ohio and Las Vegas International Speedway. How long did they run?
"Long enough that we were satisfied," says Chapman. "And long enough to bring a smile to Carroll Shelby's face."
Just as the big-block GT500 from 1968 was a step up from the GT350, the 2007 Ford Shelby GT500's 500 horsepower, 5.4-liter V-8 is a step up from the 4.6-liter V-8 used in yesterday's SVT Mustang Cobra.
Not coincidentally, the 2007 Shelby GT500 sports the largest displacement engine installed in a volume version of the Mustang since 1973.
The 1995 SVT Mustang Cobra R used a 5.8-liter 300 horsepower overhead valve V-8, and 250 units were produced. The 2000 SVT Mustang Cobra R used a 385 horsepower 5.4-liter dual overhead cam V-8, and a limited run of 300 cars was produced.
While the big block, overhead cams and four valves per cylinder contribute significantly to the 500-horsepower output of the 2007 Shelby GT500's 5.4-liter V-8, a Roots-type supercharger and intercooler are the icing on the cake. In fact, the configuration is similar to the Ford GT supercar, offering the right combination of classic Ford big-block power and modern technology. Using the Ford GT as a blueprint, SVT has given the GT500 more total horsepower than any factory Mustang in the car's celebrated history.
"The Shelby GT500 delivers on the essence of two great names in Ford performance - a mix of SVT's modern-day experience with supercharging and the Shelby GT500's heritage of big-block power," says Jay O'Connell, SVT chief vehicle engineer.
With the stout cast-iron, 5.4-liter Triton V-8 engine as a starting point, the Shelby GT500 adds a Roots-type 8.5-pounds-per-square-inch Eaton supercharger and water-to-air intercooler.
"A screw-type supercharger that we use in the Ford GT gives you a little more top end, and the Roots type is a little fatter in the midrange," says O'Connell. Given that the GT500 will be used as a daily driver far more than the Ford GT is, it's the ideal choice."
Adding forced-induction power is more than just a bolt-on proposition. The engine's internals need upgrading for the sake of strength and durability. To that end, the Shelby GT500's powerplant benefits from unique connecting rods and forged pistons to handle the extra strain on the lower end of the block.
"The entire induction system is unique," says O'Connell. "That includes the intake, intercooler, fuel supply - everything."
The all-new intake manifold helps to channel the supercharged fuel-air mixture into the cylinders. The low-profile manifold design also effectively packages the entire induction system under the GT500's special air-extractor hood. Fuel comes from a dual-bore electronic throttle body borrowed from Ford's 6.8-liter V-10 truck engine program.
To manage heat produced by 500 horses, engineers devised a set of GT500 specific features, including an air-extractor hood, a high-capacity aluminum radiator, an intercooler mounted below the blower, a loop-style power-steering cooler and an oil-to-water stacked-dish engine oil cooler.
4-Valve Heads from Ford GT
While supercharging is a key element in the Shelby GT500's ability to generate so much horsepower, another major contributing component is the design of cast-aluminum, four-valve cylinder heads sourced from the Ford GT supercar.
Machining changes are incorporated into the outside ends of the heads and to the left rear cam cap to fit the engine into the Mustang chassis.
Developed specifically for supercharged applications, these high-performance heads use high-flow ports and specially calibrated dual-overhead camshafts to deliver optimum engine "breathing" along with surprisingly good fuel efficiency and emissions.
The cams and valvetrain are specific to the Shelby GT500. The cam drive system is unique and designed to fit into the Mustang engine compartment, which is narrower than the Ford GT's. The oil pan and windage tray are the wet-sump setup from the Mustang GT. The Ford GT uses a dry-sump arrangement.
Powered by SVT
To enthusiasts, the real beauty of any performance car rests with its engine. That idea certainly wasn't lost on Carroll Shelby because Mustangs that bore his name have traditionally brought his unique sense of style and personality directly into the engine compartment. One Shelby signature feature - special finned-valve covers embossed with "COBRA Powered By Ford" - soon became the envy of many Ford V-8 owners.
The GT500 is equipped with special "Powered by SVT" finned-cam covers to hint at the beauty of all those horses lurking in the engine below. Mated to the Ford GT 4-valve cylinder heads are unique exhaust manifolds that help to better scavenge spent gases out of the cylinders and into the custom-tuned mufflers and dual-exhaust system.
And the aggressive exhaust note, which is unobtrusive in everyday driving situations, was truly custom tuned.
"More than 40 different muffler tunings were tested, measured and evaluated to come up with the right sound," says William Woebkenberg, an engineer with SVT.
A special device called a "tuned exhaust crossover" was incorporated to create the special sound. Unlike the H-pipe design used by the Mustang GT, the Shelby GT500 uses an X-shape stamping to create the desired sound and increase power output through dynamic scavenging.
The gearbox used by the 2007 Shelby GT500 also is a rarity. Few transmissions exist in the marketplace today that can handle the torque loads generated by the supercharged GT500, so engineers are opting to stick with the proven heavy-duty performance of the TR6060 6-speed manual gearbox.
The GT500 employs an upgraded version of the T-56, which first appeared in the 2000 SVT Mustang Cobra R, powered by a naturally aspirated 5.4-liter V-8 with 385 horsepower, and later in the supercharged 2003 SVT Mustang Cobra whose DOHC 4.6-liter produced 390 horses. For the Shelby GT500, the six-speed manual will be geared to make the most of the supercharged 5.4-liter's broad power band.
Then and Now
Performance cars have evolved dramatically since their heyday in the 1960s. In terms of safety, efficiency and refinement, today's street machines totally outperform their elder muscle car colleagues in nearly all categories. Yet the story is seldom told about the tremendous gains made in reducing emissions while increasing overall power output.
The fact is, the GT500 is easily twice as powerful as the hottest V-8 package offered when Mustang was first introduced - yet still produces from 100 to 300 times fewer emissions. Additionally, today's modern "MOD" V-8 powertrain enjoys a nearly 60-percent increase in average fuel economy compared to corresponding Ford products produced 30 years ago.
Back in the so-called Muscle Car era, driving a street beast with more than 400 horsepower was a dicey proposition. When dual carburetors, progressive linkage and dual-point ignitions were part of the equation, performance came with a price - drivability. Running too lean or too rich - or with the timing or spark out of adjustment -- could mean it would misfire or "carbon up", sometimes with thick black smoke coming from the tailpipe. Worse yet was fuel economy, with most of the big, high-powered V-8s at the time netting anywhere from six to 10 miles per gallon in typical driving.
Ford's "MOD" V-8 family of engines makes more power than any Ford motors of the past, yet tops 20 mpg on the highway and meet the government's LEV-II tailpipe emissions standards.
Multi-valve Engine Technology
Modern, race-derived technology provides an interesting power comparison: The GT500 with a 5.4-liter, DOHC, supercharged V-8 produces better than 100 horsepower more with nearly 100 fewer cubic inches. Compare that with the 1967 Shelby GT500's 355-horsepower, 428-cubic-inch-displacement, big-block V-8.
The GT500 uses cylinder heads with four valves per cylinder and double overhead cams for optimum engine "breathing." Using multiple valves per cylinder provides the engine with a more efficient airflow, generating higher peak horsepower. As an additional benefit, multi-valve engines better utilize the air-and-fuel mixture in the cylinders with less waste and unburned fuel vapor. Also, multi-valve engines are better suited to help scavenge exhaust gases out of the cylinder after combustion is complete for more power with cleaner tailpipe emissions.
In addition, supercharging produces the peak horsepower of a much larger-displacement, naturally aspirated engine. Yet, at lower throttle applications, the smaller displacement enabled by supercharging consumes less fuel, resulting in increased fuel economy and lower emissions.
As a result, the 2007 Ford Mustang Shelby GT500 is designed not only to be the most powerful Mustang from the factory - but also one of the cleanest.
With a body structure providing considerably more torsional rigidity than the previous generation Mustang hard top, the chassis of the 2007 GT500 coupe is better able to respond to driver inputs to help control the vehicle in emergency maneuvers.
The body structure is 31 percent stiffer in torsion, meaning that a twisting force of 15,500 foot-pounds can deform the body by only one degree. Such dramatic leaps in body stiffness contribute to the GT500's driving performance, with parallel benefits in accident protection.
Engineering a body with such high stiffness creates a passenger "safety cage" that helps protect the cabin from deformation and intrusion.
The front structure is designed to absorb energy in a controlled manner and dissipate it before it can reach the passenger compartment. The GT500 front rails have an octagonal shape to spread forces evenly at the firewall and progressively deform for increased protection in demanding offset frontal crashes.
Other safety features include all-speed traction control, anti-lock brakes (ABS) and Ford's Personal Safety System®. When you add in the standard driver and front passenger side-impact air bags and side intrusion door beams, the GT500 provides a comprehensive safety package.
GT500 Confidence: Ford Personal Safety System®
Topping the list of GT500's safety equipment is Ford's Personal Safety System®, one of the industry's most comprehensive safety technology suites. The system is designed to provide enhanced protection in many types of frontal crashes by analyzing impact factors and determining proper air bag response in milliseconds.
It uses dual-stage driver and front-passenger air bags capable of deploying at full or partial power. In less severe frontal crashes, air bags inflate with less force.
Ford's Personal Safety System® employs pretensioners to tighten front seat belts in the first milliseconds of a crash. Energy management retractors gradually slacken the belt, if necessary, to reduce forces across the occupant's chest during the impact.
Standard Front Passenger Classification Sensing
Standard front passenger classification sensing builds on the strength of the Personal Safety System™ to tailor deployment of the front-passenger air bag. If the passenger-seat sensor detects no weight or very little weight, like a newspaper or a jacket, the passenger air bag is automatically switched off.
If more weight is on the seat, like a small child, the air bag remains deactivated and an instrument panel light alerts the driver with the message "PASSENGER AIR BAG OFF." Of course, the safest place for children remains the rear seat, properly restrained. If an adult is seated properly in the passenger seat, the air bag automatically is switched on, ready to inflate within milliseconds, if needed.
Among the dozens of standard safety and security features the GT500 offers are:
- BeltMinder™ - The most effective way to help save lives on roadways is one of the simplest safety technologies on the market - the safety belt. Ford's BeltMinder™ system gives occupants a gentle chiming reminder to fasten their safety belts. A Ford innovation introduced in 1999, BeltMinder™ already is proving to increase safety-belt use.
- SecuriLock™ Passive Anti-Theft System - Passive anti-theft systems like SecuriLock™ help protect against drive-away theft through the use of an electronically coded ignition key. The system is designed to help prevent the engine from being started unless a coded key programmed to the vehicle is used. A miniature transponder with an integrated circuit and antenna is imbedded in the ignition key. A wireless radio-frequency transmission transfers an electronic code between the transponder in the key and the vehicle. If the codes match, a signal passes through the wiring system to the electronic engine control, allowing the vehicle to start.
- Battery Saver - Battery Saver helps prevent accidental battery drainage from Mustang's interior lights. The battery saver feature automatically turns off interior lights in a parked vehicle after a few minutes, like when a door is left ajar. If interior lights are left on while the ignition is in the Off position, a relay is deactivated in 10 to 40 minutes cutting power to the interior lights.
- Fail-Safe Cooling - A fail-safe cooling system lets GT500 be driven under limited power for short distances if engine coolant is lost, eliminating the cost and inconvenience of towing. If the coolant level sensor reads below a critical level, the engine computer module switches the engine to an emergency limp-home mode, in which only half the cylinders get fuel. With only half the cylinders firing, the engine operates at lower power and generates much less heat. The cylinders alternate between even- and odd-firing pistons in this mode. The engine can move the vehicle at moderate speeds (up to about 50 mph).
Keeping the Shelby Where It Belongs
The GT500 also features an active anti-theft package aimed at combating high performance-car insurance premiums. The package includes:
- Separate Alarm Sounder - The GT500 employs a separate, remotely located alarm sounder in conjunction with the traffic horn, making it harder for thieves to disable the system and make off with the car or its contents.
- Anti-Tow Sensor - The vehicle is guarded against tow-away thefts. An inclination-sensing module records the vehicle's angle when the anti-theft system is armed. If the sensor detects a change in vehicle incline, it sends a signal to the alarm system, which triggers a separate alarm, traffic horn and flashes the car's lights.
- Ultrasonic Interior Motion Sensor - To detect "smash-and-grab" break-ins, an ultrasonic interior-motion sensor is designed to detect motion inside the vehicle cabin. If an intrusion is detected, the alarm sounder and traffic horn are activated and the exterior lights flash to frighten would-be thieves.
- Perimeter Anti-Theft Protection - Perimeter anti-theft sensors also detect the opening of the hood, doors or trunk when the anti-theft system is armed. If the vehicle is parked and the window rolled down, for example, the alarm is sounded if a would-be-thief tries to open the door to gain access to the car.
- High-Capacity Battery - A 60-ampere-hour battery is capable of sounding the alarm longer. This powerful battery lends an extra measure of authority to the active anti-theft system and helps prevent battery run-down from use of GT500's powerful audio system while the engine is off.
Carroll Shelby has always been a fierce competitor, both on the track and in business. He does not like to lose.
"About the only thing I like less than losing is losing and not learning from it," says the racing great.
That philosophy sums up how Shelby, superchargers and Mustangs came together in the first place.
The story begins in 1965 when a supercharger manufacturer tried to interest Shelby in putting its product on his then-new GT350 Mustang. At the time, Shelby's plate was full with building, selling and racing cars. He declined.
Then the manufacturer's rep showed up at Shelby's shop in the shadow of the Los Angeles airport with a supercharged GT350. Shelby agreed to a race on the vast expanses of empty concrete that surrounded the airport. He jumped behind the wheel of a 289 Cobra roadster - a vehicle much lighter than the 289 GT350 - and soundly lost.
"Well, I figured if that rep was going to teach me a lesson I might as well profit from it," he says. "So for the 1966 model we made a supercharger a factory option on the GT350 as well as an aftermarket accessory."
A supercharger remained in the Shelby catalog right through the end of production of the original Shelby Mustangs. It was offered on GT350 models. In 1966 and 1967 these were powered by the 289 cubic-inch V-8. In 1968, displacement was boosted to 302 cubic inches. Beginning in 1969, the GT350 sported Ford's then-new 351 cubic-inch V-8.
Using a Blower to Call Down the Thunder
However, these were not the first - nor, obviously, the last - production Ford passenger vehicles to be supercharged.
Thunderbird and supercharger have long been synonymous. The relationship began in 1957 when a supercharged version of the "Y-block" 312 cubic-inch V-8 was offered as a more powerful alternative to the two non-blown engine choices. Output of the standard Thunderbird four-barrel 312 was rated at 245 gross horsepower. A dual four-barrel version generated 270 gross horsepower. However, the supercharged engine topped them both with a gross rating of 300 horsepower.
Thunderbirds and superchargers would not meet again until the 1989 model year when the Thunderbird Super Coupe was introduced. This time around, the engine was a V-6 displacing 3.8 liters. From 1989 through 1993, the Super Coupe carried a net rating of 210 horsepower and 315 lbs.-ft. of torque. This was upgraded to 230 horsepower and 330 lbs.-ft. for the 1994 and 1995 model years.
SVT Finds Special Uses for Superchargers
Superchargers have also played an important role in the history of the Ford Special Vehicle Team.
SVT's first production vehicle to use a supercharger was the F-150 Lightning. An all-new F-Series platform gave SVT engineers a "clean-sheet" opportunity for the 1999 model year. SVT started with the smallest, lightest F-150 chassis for optimum acceleration and handling - the sporty short wheelbase, Regular Cab FlareSide configuration. Engineers lowered the truck two inches in the rear and half an inch in the front, added big brakes and a sport-tuned suspension as well as unique front and rear styling treatments.
However, the big news was a special SVT-developed supercharged 5.4-liter Triton™ V-8. Output was an arresting 440 lbs.-ft. and a mighty 360 horsepower - 40 more horsepower than even SVT's flagship 1999 Mustang Cobra generated. Needless to say, the 1999 SVT F-150 Lightning set new standards for full-size sport trucks. For 2001, SVT bumped up the Lightning's output to 380 horsepower and 450 lbs.-ft.
Meanwhile, engineers were learning the lessons that eventually would pay off in the form of the 2007 Shelby GT 500.
Introduced as a 2003 model, the SVT Cobra took Mustang horsepower to as-yet unseen heights with a new, Eaton supercharged DOHC 4.6-liter "Terminator" V-8. Rated at 390 horsepower and 390 lbs.-ft. of torque, it was among the most powerful Mustangs ever to leave the production line up to that time. It also featured a 6-speed manual transmission, redesigned front and rear fascias and a new "heat-extraction" hood.
A blueprint for the future had been drawn.