2005 Ford Mustang Set to Capture American Hearts – Again

- Driving Dyamics

A new-from-the-ground-up chassis and careful attention to vehicle dynamics give the all-new Mustang world-class ride and handling.

The starting point is an all-new, purpose-built, muscle-car platform with exceptional body stiffness and a very high strength-to-weight ratio. With this ultra-rigid structure, Mustang engineers could tune spring, damping and bushing rates to a finer degree than ever possible.

Using computer-aided design and engineering technology, the Mustang team took months off the earliest phases of component development. That gave driving dynamics experts more time to work out final chassis tuning – and they used it to deliver an unprecedented combination of road handling and comfort in the 2005 Mustang.

Track time – at drag strips and on road courses – was a critical part of development, as chassis engineers pushed prototypes to the limit in search of the perfect power-and-handling blend.

"We spent countless hours refining this car on development drives and at the track," said Mark Rushbrook, vehicle development manager. "The car has been to the Nelson Ledges road course in Ohio several times for 24-hour runs and has spent months on our own straightaways and handling courses at our proving grounds in Arizona, Michigan and Florida."

Street time was just as important. Mustang is a muscle car designed for everyday driving, and it must deliver a quiet, comfortable, reassuring ride in a real world plagued by potholes and uncertain road conditions. By the time testing is completed, prototypes of the new Mustang will have logged nearly 1 million miles on streets, highways and tracks throughout the United States, Canada and even Sweden in all types of weather.

A quiet cabin – where unwanted road and wind noise is supplanted by the signature growl of a Mustang engine – was a top development priority. Computers carefully mapped the natural vibrating frequencies of body components to pinpoint areas where unwanted noise was transmitted. Based on this data, components were modified or material was applied to quell the unwanted noise. Despite the new, quieter interior, the car still has plenty of "character." There will be no mistaking it for something other than a Mustang.

The result is a car that delivers the edge – the performance characteristics Mustang buyers demand – along with the smooth – a more civilized environment that makes for a pleasant driving experience on long trips or in more routine travel about town.

Front Suspension – Born to Run like a Mustang

One of the more critical development areas was the front suspension, where the Mustang design team delivered a high degree of precision handling, coupled with a smooth ride, all while harnessing the power a top-of-the-line GT can deliver.

Engineers carefully examined the BMW M3, a car believed by many to deliver just such qualities, before they laid out the Mustang's suspension. They used lessons learned from the M3 and the Lincoln LS to create the new Mustang's chassis design.

Mustang engineers settled on using a coil-over MacPherson strut front suspension with reverse "L" lower control arms made of lightweight I-section steel. MacPherson struts – originally developed in the 1940s by Earl S. MacPherson, a Ford engineer – are widely renowned for their ability to deliver both comfort and control with reduced weight.

The L-shaped lower control arms offer additional advantages over A-arm or wishbone-shaped suspension components when it comes to blending sure handling with ride comfort. A firm bushing is positioned at the point where the shorter forward leg of the L-arm connects to the chassis to control side-to-side motion and quicken steering response. The fore-and-aft movements are directed through a softer, compliant bushing at the longer, rear L-arm leg, which damps road shocks. This isolation is a direct benefit of the reverse L-configuration of the control arms.

Springs are mounted concentrically on the MacPherson struts in a coil-over-shock configuration. The layout allows the shocks to damp forces in the same vector as the spring, cutting friction and enabling more precise shock-valve tuning. A stabilizer bar – 34 mm on the GT and 28.6 mm for V-6 models – helps limit body roll.

At the core of Mustang’s advanced new front suspension is groundbreaking manufacturing technology used to produce steel control arms that actually weigh less than some comparable cast-aluminum designs.

Employed for the first time in a production vehicle, this new manufacturing technique allows two C-section stampings to be assembled back-to-back with welded seams. This creates an I-section profile that offers an exceptional strength-to-weight ratio. Material is efficiently moved toward the edges of the control arms for increased stiffness, while the center is kept thin to
minimize weight.

Reducing unsprung weight – components that are positioned below the springs and shocks – improves the suspension’s response to abrupt changes, like pavement seams. Drivers will feel more connected to the road, while enjoying a smoother, quieter ride.

"Having too much unsprung weight is like trying to play basketball in ski boots," said Rushbrook. "Keeping the unsprung weight low gives the suspension the quickness to stay firmly planted to the road."

The new steering system not only makes Mustang more enjoyable to drive on the open road, it also greatly improves parking lot maneuverability. The rack-and-pinion linkage provides crisp turn-in and excellent response, with a turning circle nearly 3 feet smaller than the 2004 model.

Rear Suspension – Mustang’s Solid New Design

Working on a clean sheet of paper, Mustang’s engineering team could have selected any type of setup at the rear, including an independent suspension. So why choose a solid rear axle? The answer lies in Mustang’s position as America’s sports car.

"We talked to a lot of Mustang owners when we were developing this program," said Hau Thai-Tang, chief nameplate engineer. "They are a very passionate group, and a lot of them told us – very strongly – that the all-new Mustang must have a solid rear axle."

Although a mainstay of muscle-car design, the solid axle hasn’t always been viewed as its strong suit. Early hopped-up sedans often overwhelmed their leaf-spring live axles, which weren’t designed for the demands of performance driving. The slender leaf springs were prone to side sway in hard maneuvers and to wind up and "hop" the rear wheels under full throttle. The tendency of the low-grip bias-ply tires of the day to lose traction and "burn rubber" actually was a blessing in disguise, as it took pressure off the suspension.

For 40 years, Mustangs have featured ever-improving solid rear axle designs.

For 2005, Mustang’s rear suspension takes a completely different approach to combat wheel hop. Engineers opted for a three-link architecture with a Panhard rod that provides precise control of the rear axle. A central torque control arm is fastened to the upper front end of the differential, while trailing arms are located near each end of the axle.

A lightweight, tubular Panhard rod is parallel to the axle and attached at one end to the body and at the other to the axle. It stabilizes the rear axle side-to-side as the wheels move through jounce and rebound. It also firmly controls the axle during hard cornering.

Constant rate coil springs and outboard shocks are tuned for a firm, yet compliant, ride. The shocks are located on the outside of the rear structural rails, near the wheels, reducing the lever effect of the axle and allowing more precise, slightly softer tuning of the shock valves.

The GT version of the car incorporates a separate rear stabilizer bar to reduce body lean further.

Previous Mustangs used a simplified rear suspension linkage that acted on composite force vectors. By using separate longitudinal and lateral links in the all-new Mustang, engineers could isolate the forces acting on the rear axle and tune the bushings accordingly. As a result, the axle is more precisely controlled throughout its range of motion. Road shocks are isolated and damped, and the solid lateral control of the rear axle reduces body sway and improves control and stability over mid-corner bumps.

The solid rear axle offers several other advantages that play to Mustang’s strengths. It is robust, maintains constant track, toe-in and camber relative to the road surface, and it keeps body roll well under control.

In short, the Mustang’s sophisticated rear geometry provides handling precision and performance worthy of a modern muscle car. But that doesn’t mean any of the fun has been dialed out of the new model. Keeping enthusiasts in mind, Ford chassis and powertrain engineers worked together to make sure owners of the new Mustang still can "chirp" the rear tires when the spirit moves them.

Brakes – Adding Whoa to the Go

Bigger usually means better when it comes to brakes, but that is only part of the story behind the 2005 Mustang’s sophisticated standard four-wheel-disc braking system.

Along with Mustang’s biggest-ever rotors and stiffest calipers, comes a new, four-channel anti-lock braking system. Standard on GT and optional on V-6, it enhances braking performance. In addition to helping prevent wheel lock-up, the new system has electronic brake force distribution, which distributes braking power to the wheels where it can be used most effectively.

Dual piston aluminum floating front calipers clamp down on 316 mm (12.4-inch) front brake discs on GT models – an increase of more than 15 percent in rotor size. On the GT, the brakes have 14 percent more swept area than those of the previous model. These rotors are 30 mm thick and are ventilated to provide consistent stopping power, even under the strain of excessive heat induced by repeated hard braking. The payoff comes in shorter stopping distances, better pedal feel and longer pad and rotor life.

The V-6 Mustangs get 293 mm (11.5-inch) ventilated rotors that also are 30 mm thick. This represents a 6 percent increase in rotor size over the previous V-6 Mustang brakes.

In the rear, the brake rotors are 300 mm (11.8 inches) in diameter – more than 12 percent larger than the previous Mustang – and 19 mm thick. Rear rotors are vented on both the GT and V-6. Single-piston calipers sweep 18 percent more area than the rear brakes on the previous Mustang.

Gripping Profile: New Mustang Wheels and Tires

No muscle car deserves the title unless suited up with the proper wheels and tires, and the new Mustang won’t leave the factory half-dressed. The array of wheels available on the 2005 Mustang is engineered to meet demanding performance requirements.

The standard 17-inch wheels on Mustang GT are 8 inches wide and equipped with Pirelli P235/55ZR17 W-speed-rated all-season performance tires for year-round driving.

V-6 models have 7-inch-wide, 16-inch wheels. As with the Mustang GT, all-season rubber is standard, with a slightly higher profile S-rated BF Goodrich tire, sized at P215/65R16. These tires are designed to offer long wear without compromising performance.

In concert with the ABS and traction control systems, the new, all-season tires make Mustang more practical in rain, ice or snow. On dry pavement, they provide an exceptionally engaging driving experience with high overall grip and good steering response.

Aesthetically, street rodders long have known that larger wheels and tires better fill the car’s wheel wells, adding meat to the muscle. The 2005 Mustang’s tires boast more sidewall than many other sports cars, enhancing the muscle car look and providing a better match for this vehicle’s blend of power and handling.