2012 FORD MUSTANG BOSS 302 BRINGS ROAD RACING LEGEND BACK TO THE STREETS
The Boss returns! Limited production 2012 Mustang Boss 302 set to become the quickest, best-handling straight-production Mustang ever offered by Ford, based on the world-class foundation provided by the 2011 Mustang GT
Boss upgraded in nearly every vehicle system; engine output, brakes, suspension, interior and exterior all examined to optimize weight, aerodynamics and track performance
Full Mustang team effort results in a comprehensive re-engineering available only through the factory; new Boss is not a package that can be purchased out of a catalog or achieved through tuning or aftermarket parts
Limited-production track-oriented Boss 302 Laguna Seca model expands on Boss racing aspirations, deleting rear seat and adding race-ready suspension and aerodynamic treatments
Ford gave the green light only once before: In 1968, management approved a special Mustang – a car that sacrificed nothing in its quest to be the best all-around road-going performance machine ever created by Ford Motor Company. That car became the 1969 Mustang Boss 302, and it remains one of the world’s most sought-after examples of American performance.
Forty-two years later, Ford has given the green light again.
The team of Ford engineers, designers and stylists – all Mustang enthusiasts to the core – that created the groundbreaking 2011 Mustang GT has distilled a new model to its purest form, strengthening, lightening and refining each system to create a race car with a license plate. Its name: the 2012 Mustang Boss 302.
“The decision to build a modern Boss was not entered into lightly,” said Derrick Kuzak, group vice president, Global Product Development. “The entire team at Ford felt the time was right and with the right ingredients, the world-class 2011 Mustang could support a successful, race-bred, worthy successor to the original Boss 302. For us that meant a production Mustang that could top one of the world’s best – the 2010 BMW M3 – in lap times at Laguna Seca. We met our expectations.”
To celebrate the racing heritage of the new Mustang Boss 302, Ford will also offer a limited number of Boss 302 Laguna Seca models, named for the track where Parnelli Jones won the 1970 Trans-Am season opener in a Boss 302. Aimed at racers more interested in on-track performance than creature comforts, the Boss 302 Laguna Seca has increased body stiffness, a firmer chassis set-up and an aerodynamics package carried over almost in its entirety from the Ford Racing Boss 302R.
Philosophy and powertrain
“The new Boss 302 completely redefines Mustang capability,” said Mark Fields, Ford president of The Americas. “That the Mustang team was able to take the current Mustang GT – already a world-class performance car – and refine it further for peak track performance shows the commitment Ford has to this car and its legions of fans.”
Driving the 2012 Mustang Boss 302 was intended from the outset to be a visceral experience, packed with raw, unbridled performance across the spectrum: Acceleration, handling, braking, and top speed are all equally matched for perfect balance on a car operating within the framework of legally defined safety, noise and emissions regulations.
“The team at Ford wanted to offer their fellow Mustang enthusiasts something really special – a beautifully balanced factory-built race car that they could drive on the street,” explains Dave Pericak, Mustang chief engineer. “The Boss 302 isn’t something a Mustang GT owner can buy all the parts for out of a catalog or that a tuner can get by adding a chip. This is a front-to-back re-engineered Mustang with every system designed to make a good driver great and a great driver even better.”
Led by Mike Harrison, the V8 engine team approached Boss from the top down: With 412 horsepower from 5.0 liters, the 2011 GT engine was already an incredible performer. But to achieve the high-rpm horsepower that would make the engine competitive on the track, a new intake was essential. The resulting runners-in-the-box plenum/velocity stack combination the engine team developed was impressive enough that it got the green light after one short drive.
Helping the intake build power, revised camshafts using a more aggressive grind are actuated with the same twin independent variable camshaft timing (Ti-VCT) mechanism used on the Mustang GT. More aggressive control calibration yields 440 horsepower and 380 lb.-ft. of torque, while still offering a smooth idle and low-end torque for comfortable around-town driving.
A race-inspired clutch with upgraded friction materials transmits power, while a short-throw, close-ratio six-speed manual transmission handles gear change duties.
Power is delivered to a 3.73 ratio rear axle using carbon fiber plates in the limited-slip differential to improve torque handling and longevity. For those who want even more precise control over power delivery, a torque-sensing (Torsen) limited-slip differential is an available option coupled with Recaro front seats.
Sounds like the Boss
While the powertrain team defined output targets that would yield an ideal balance with the chassis, another team made sure the car made the kind of sounds owners and enthusiasts would expect from a Mustang Boss.
Up front, a Boss-specific intake system is tuned to feed the engine with minimum restrictions. A retuned induction sound tube provides concrete aural evidence of what’s occurring under the hood. And, in the Boss exhaust system engineers really had some fun.
“With an exhaust system, we have to consider three constraints: legal noise restrictions; backpressure, which can rob power; and ground clearance,” explains Shawn Carney, Mustang NVH engineer. “Since the 2011 Mustang GT exhaust is already so free-flowing – it came in way under our backpressure targets – we already had excellent performance; we were able to tune the exhaust system for a unique sound. Combined with the rush of the intake, the exhaust system really envelops the driver in V8 sound.
Every Boss features a unique quad exhaust system: Two outlets exit in the rear similar to a standard Mustang GT. The other two outlets exit to either side of the exhaust crossover, sending exhaust through a set of metal discs that act as tuning elements before the pipes terminate just ahead of the rear wheel opening. Visually subtle, the side pipes flow very little exhaust but a lot of exhaust sound, providing a sonic experience unlike any other Mustang.
Suspension and steering
In keeping with the Boss mandate to provide the best-handling Mustang ever, the already strong Mustang GT suspension system has been further refined. Higher-rate coil springs on all four corners, stiffer suspension bushings and a larger-diameter rear stabilizer bar all contribute to the road racing mission, and Boss models are lowered by 11 millimeters at the front and 1 millimeter at the rear versus the Mustang GT. The real key to handling, though, is in the adjustable shocks and struts, standard on all Boss Mustang models.
“We’ve given drivers five settings for their shocks,” says Brent Clark, supervisor of the Mustang vehicle dynamics team. “One is the softest, two is the factory setting and five is the firmest, and we’ve provided a wide range of adjustment. A customer can drive to the track on setting two, crank it up to five for improved response on the track, then dial down to one for a more relaxed ride home. What’s unique is that drivers will find – thanks to the way the suspension works as a complete system – the softest setting isn’t too loose and the firmest setting isn’t too controlled; each step just provides additional levels of control.”
Also unique is the method of shock adjustment. Ditching the weight and complexity of electronic wizardry, the Mustang team opted for traditional race-style hands-on adjustability – similar to the Gabriel shocks available on the original Boss 302.
“The shock adjustment is right at the top of the shock tower, built into the rod and easily accessible from under the hood or inside the trunk,” says Clark. “You just take a small flat-head screwdriver, turn the adjustment screw between one and five, and head back out onto the track.”
To complement the suspension, the speed-sensitive electronic steering system has been retuned to maximize feedback and road feel to the driver. The driver is also given the option of fine-tuning the steering feel to his liking by selecting one of three settings through the instrument cluster menu: Comfort, normal and sport modes help offer track-tuned steering when desired without sacrificing low-speed maneuverability in parking situations and everyday commuting.
Similarly, Boss receives unique traction control system (TCS) and electronic stability control (ESC) settings to help drivers achieve maximum performance whether on the street or at the track. Both systems can be completely disabled in controlled track situations where maximum driver skill is utilized, or fully engaged for maximum safety during normal driving or in less-than-ideal traction conditions. Intermediate sport mode allows drivers to push their cars hard at the track without completely disabling the safety systems, permitting more aggressive driving before the TCS and ESC systems intervene.
Brakes, wheels and tires
Working in concert with the suspension upgrades, Boss 302 receives unique, lightweight 19-inch black alloy racing wheels in staggered widths: 9 inches in front, 9.5 inches in the rear. The Pirelli PZero summer tires are sized specifically for each end of the vehicle, with the front wheels receiving 255/40ZR-19 tires while the rear stays planted thanks to 285/35ZR-19 rubber.
The combined suspension and tire package allows Boss to achieve a top speed of 155 mph and become the first non-SVT Mustang ever to achieve more than 1.0 g of lateral acceleration.
Boss braking is also up to the challenge, using Brembo four-piston front calipers acting on 14-inch vented rotors up front. In the back, standard Mustang GT brakes are upgraded with a Boss-specific high-performance pad compound. Combined with vented brake shields and unique Anti-Lock Brake System (ABS) tuning, Boss drivers get maximum control and rapid, repeatable fade-free stops in road and race situations alike.
The Mustang team spent considerable time ensuring the brake pedal feel met the expectations of performance drivers. Boss receives unique low-compressibility brake lines that expand up to 30 percent less than traditional flexible brake lines, allowing maximum fluid pressure to reach the calipers in the least amount of time, giving the driver a sensation of being connected directly to the brake pads.
“This car is wicked fast, so we put a lot of emphasis on giving it comparable stopping power,” says Clark. “We started with a race-proven brake system and tuned it specifically for the characteristics of the Boss 302 and its mission. They’re the best brakes ever installed on a Mustang, and they give consistent, repeatable braking performance on the street and the track.”
As a result 60-0 stopping distances for the Boss are improved by approximately three feet versus the Mustang GT with available brake package; combined with suspension and engine improvements, Boss is expected to show approximately a two-second lap time improvement over the GT on a typical road race course. But the numbers tell only part of the story.
“We achieved measurable improvements over GT, which was already one of the best-braking cars we’ve ever designed,” explains Clark, “but what’s harder to quantify is how good these brakes feel to a driver in a race situation. Like everything on this car, the brakes are more than the sum of their parts: They’re tuned from pad to pedal to work perfectly as a system, and the difference is dramatic.”
Exterior and interior design
Changes to the Mustang Boss exterior are subtle but unmistakable. True to its race-bred heritage, every component that could potentially aid aerodynamics or engine/brake performance was examined to make the vehicle more competitive, while chief designer Darrell Behmer refined the styling to evoke the 1969 Boss in a contemporary way.
“We approached this as curators of a legend,” explains Behmer. “We’ve taken design cues from the ’69 Boss street car and the menacing Bud Moore/Parnelli Jones race cars and carefully updated them to give the 2012 the proper bad-boy attitude that is unmistakably a Boss Mustang.”
To set Boss apart, each car will have either a black or white roof panel, coordinated to the color of the side C-stripe. Available exterior colors are Competition Orange, Performance White, Kona Blue Metallic, Yellow Blaze Tri-Coat Metallic and Race Red.
Up front, a unique fascia and grille are highlighted by the blocked-off fog lamp openings and aggressive lower splitter, a version of the design used – and proven – on the Boss 302R race car. The front splitter is designed to function at high speeds by efficiently managing the air under and around the car. It helps to reduce underbody drag and front end lift while more effectively forcing air through the Boss-specific cooling system. At the rear of the car, the spoiler was chosen to complement the front aero treatment and minimize overall drag.
“What we were after on Boss was reduced overall lift with improved balance,” says Pericak. “We needed to keep the car glued to the street or the track at high speeds without increasing drag or affecting top speed and fuel usage. The end result is an aero package that uses front, rear and underbody treatments not for show, but for effect – the balance and stability of this car all the way to its 155-mph top speed is just outstanding.”
Inside, a unique Boss steering wheel covered completely in Alcantara suede complements the standard seats, which are trimmed in cloth with a suede-like center insert to firmly hold occupants in place. Boss customers who want the ultimate seating experience can select a package that includes Recaro buckets, designed by Ford SVT in cooperation with Recaro for high performance Mustang models, and shared between the Boss and GT500.
A dark metallic instrument panel finish, gauge cluster and door panel trim also differentiate Boss from the standard Mustang, while a black pool-cue shifter ball and “Powered by Ford” door sill plates further remind customers they’re in a special car.
The Boss interior gets an aural kick thanks to what’s been removed. Eleven pounds of sound-deadening material have been eliminated to let occupants further enjoy the intake, engine and exhaust note.
“Boss is a hallowed word around here, and we couldn’t put that name on a new Mustang until we were sure everything was in place to make this car a worthy successor,” explains Pericak. “We were either going to do it right or not do it at all – no one on the team was going to let Boss become a sticker and wheel package.”
2012 Mustang Boss 302 Powertrain
HIGH-REVVING FORD 5.0-LITER V8 DELIVERS POWER, SPEED, FLEXIBILITY BEFITTING THE BOSS NAME
2012 Ford Mustang Boss 302 engine delivers 440 horsepower and 380 ft.-lbs. of torque without the aid of forced induction
Purpose-built Boss engine is based on production 2011 Mustang GT 5.0-liter DOHC V8, heavily modified with unique, Boss-specific parts to withstand all-day thrashing
Revised intake, CNC-machined heads, lightened valvetrain and strengthened reciprocating assembly result in a race-proven engine meeting production durability standards
The all-new 5.0-liter dual-overhead camshaft (DOHC) V8 in the 2011 Mustang GT already is the most powerful naturally aspirated production V8 Ford has ever produced. To make it worthy of the Boss name, Ford engineers tweaked more than a few bits of the engine.
They reengineered an entire dynamometer cell to handle the engine’s projected 7,500 rpm redline; put the first engines into Boss 302R race cars and sent them straight onto the track; and they designed a torture test equivalent to running the Daytona 250 race flat-out more than 175 times – in a row.
Only when the 440-hp V8 passed these tests, ensuring maximum power output without sacrificing durability, reliability and drivability, was it worthy of being called a Boss.
Bulletproof and blower-free
Planning began with a small group of engineers within the 5.0-liter V8 team. Starting with open minds and enlisting the help of two members of the original 1969 Boss 302 design team, the group began working its way toward the ultimate evolution of the new 5.0-liter: 440 horsepower and 380 lb.-ft. of torque, along with a broad, flat output curve all the way through its projected 7,500 rpm redline.
The Mustang team knew a supercharger would be the simplest way to extract significant power improvements from the new 5.0-liter V8, but they elected not to pursue forced induction for the 2012 Boss to stay true to the original Boss 302 engine.
“The core group of engineers on the Boss 302 engine understands and respect the heritage of the name and the history behind the original engine,” explains Mike Harrison, Ford V8 engine program manager. “The first Boss 302 was a specially built, free-breathing, high-revving small V8 that gave it certain desirable characteristics on a race course – and we capture that essence in the new engine.”
The team also realized the additional hardware meant more weight, the bane of any racing program and the opposite of what the Boss design team was attempting to achieve. Instead, the same technology that has made the new Mustang GT engine such a formidable force was applied to the Boss 302.
“In keeping with the spirit of the original, the new Boss 302 engine achieves its maximum power output at speeds at or above 7,500 rpm,” says Harrison. “Unlike the original engine, however, low-speed torque and driveability are uncompromised thanks to twin independent variable camshaft timing (Ti-VCT) technology and computer-aided engineering design tools.”
Harrison and his team began exploring Boss 302 concepts starting with the engine’s ability to breathe – essential to the production of horsepower. Because credible track performance requires high power production between 5,000 rpm and 7,000 rpm, the team needed a new approach to intake manifold design.
Borrowing from the Ford Daytona Prototype engines, the resulting short-runners-in-the-box design virtually eliminates lag when the throttle is snapped open while producing peak power output at high rpm.
“The effect of the new intake design is dramatic,” says Harrison. “When I took the prototype car to Mustang Chief Engineer Dave Pericak, he took a short drive, tossed me the keys and said ‘Book it…it’s in the program.’ He knew what we were onto, and that’s really the point where the Boss 302 was born.”
To take advantage of the racing intake manifold, cylinder head airflow was fully optimized by CNC porting the entire intake and exhaust port and combustion chamber. The painstaking machining process takes 2.5 hours per head to complete.
To accompany the higher peak-power engine speed, the team had to engineer a lightweight, high-speed valvetrain and bulletproof reciprocating assembly that would not only hold together for 150,000-plus miles but also produce power at peak rpm.
“What most people don’t realize is that engine stresses increase exponentially as engine speeds rise,” explains Harrison. “So moving up from GT’s 7,000 rpm redline required significant re-engineering of many different parts. Sacrificing reliability and usability over the GT engine was never an option.”
Some of the Boss-specific parts contributing to the Boss 302 V8’s output and durability include:
- Revised composite intake system with shorter runners, inspired by Daytona Prototype racing engines, for high-rpm breathing
- Forged aluminum pistons and upgraded sinter-forged connecting rods for improved strength, needed for the higher combustion pressures and engine speeds
- New high-strength aluminum-alloy cylinder heads with fully CNC-machined ports and chambers for exceptional high-rpm airflow without sacrificing low-speed torque
- Lightened valvetrain components to provide excellent dynamic performance up to speeds well above the engine redline
- Sodium-filled exhaust valves for improved heat dissipation
- Race-specification crankshaft main and rod bearings for higher load capability and improved high-speed durability
- 5W50 full-synthetic oil with engine oil cooler for improved oil pressure and longer-lasting lubrication during extreme racing conditions
- Revised oil pan baffling for improved oil control under racing conditions and during cornering loads greater than 1.0 g
- Close connection with race teams
Contrary to normal engine development protocol, the first batch of durability test engines weren’t installed in an engine dyno. Instead, thanks to a request from Ford Racing, they went straight to the track.
“Ford Racing had challenged the Boss engine team to give them the first available Boss 302 engines,” explains Harrison. “They came to us in August 2009 and told us they needed engines as soon as possible to build a limited number of Ford Racing Boss 302R cars for the January Daytona race. They got the engines 12 weeks later and the team got five Boss 302R cars prepped for the January race. This gave us a fantastic opportunity to be able to get full-on race experience with the engine so early in the program.”
The Boss engines have run reliably all season without a single mechanical failure. Boss 302R cars have also racked up the most laps led so far this season in Grand-Am racing.
Using race telemetry, the Boss team has been able to gather on-track data to help optimize engine calibrations, oil pan designs and cooling. In order to engage in virtual racing whenever they needed, the team used the telemetry data to re-create a hot lap at Daytona on the dyno back in Dearborn, allowing further fine-tuning.
“Working with Ford Racing has been invaluable,” said Harrison. “They were a wealth of information for setting up torque and power curves for road racing and for identifying areas of concern during track runs that we wouldn’t have considered if we were just building a hot street engine. Every Boss 302 owner will benefit from their contributions to the program.”
Production engine durability testing
Despite its racing heritage – and the rigors of track-day testing – the Boss 302 V8 is still a production Ford engine, built alongside the 5.0-liter GT engine at Essex Engine Plant in Ontario, Canada. That means it has to meet or exceed all the standard durability testing every Ford engine is required to complete.
The high-winding engine presented a challenge: The engine had no trouble staying together at its redline, but the Ford durability dynamometers weren’t designed to operate at the speeds the Boss engine was capable of.
“Ford had no engine test cells built to run at that kind of sustained speed,” said Harrison. “Ford Racing had one, but it wasn’t instrumented to do production durability testing. So we had to re-engineer the dyno cell with new balancers and jackshafts so the dyno wouldn’t fly apart running at redline hour after hour.”
Once an adequate test stand was configured, the Boss engine was run at its full rated output for tens of millions of cycles, eventually outperforming its specifications at every stage of testing. Engineers calculated that the test regimen was equivalent to running the Daytona 250 race flat-out more than 175 times – in a row.
Team members also devised an additional durability test specific to the Boss 302 engine – one that reflects the unique demands of Boss drivers. The engine was subjected to a regimen simulating 1,500 quarter-mile races typical of events at drag strips across the country.
“Even though the production Boss engine is designed to be very close to a full race engine, it had to achieve the same vehicle durability signoff any other production engine requires,” says Harrison. “Then it went on to get the track durability test signoff too. It’s really an engineering accomplishment that a Boss owner can thrash his car on the track and still expect the same outstanding reliability that the owner of a regular Mustang GT will enjoy.”
