New king of the road?
Shelby GT500KR aims for perfect balance in power, handling in bid to become highway icon
One old almost religious saw of the muscle car era of the 1960s said " ... and so it shall be ... Shelby ... "
The latest version of Shelby's automotive magic -- which have included the famous Cobras and the Dodge Viper -- is the new 2008 Ford Shelby GT500KR.
Ford's Special Vehicle team (SVT) and Shelby Automobiles Inc. teamed to produce what Ford marketing says is a car with driving dynamics as big of an eye-opener as its acceleration, torque, horsepower and stopping performance.
Shelby got to do a little recent bragging himself. On April 16, the-85-year-old icon was handed the 2008 Automotive Executive of the Year Lifetime Achievement Award, honoring a career of excellence in the automotive industry.
Shelby's inspiration and vision have made him the force behind many of the industry's most beloved automobiles, including the Cobra, Series 1, Ford GT40, Viper, Ford Shelby Mustangs and the Ford GT. He captured three national sports car championships and earned a spot on the Aston-Martin racing team. In his driving career, he has won the 24 Hours of Le Mans and set land speed records on the Bonneville Salt Flats. He is the only one to ever win Le Mans as a driver, team owner and manufacturer.
The new GT500KR's handling is the result of a combination of chassis engineering and aerodynamic honing.
"The new GT500KR handling story is all about balance," said Jamal Hameedi, chief engineer of Ford SVT.
"That's the big result with new GT500KR dynamically," said Gary Patterson, Shelby Automobiles chief test driver. "Its balance makes this car very confident and predictable to drive, even on the limit."
Just as on the race track, aerodynamics has played a major role in shaping the dynamic capabilities of the 2008 GT500KR.
"Our objective was to build on the GT500 to give the new model more dynamic balance, reflecting its higher power output," said John Pfeiffer, SVT product design engineering specialist. "We focused our efforts on creating even downforce levels front and rear. That meant finding more frontal downforce than the previous model."
Extensive engineering work was devoted to deliver more front downforce, starting with the most obvious aerodynamic feature on the new car: its slick carbon-fiber front splitter.
The new splitter is an all-new profile, more aggressive than that of the GT500. It is deeper and consistently full in shape, mirroring the shape of the leading edge of the hood and bumper above it for design coherence.
The thinner splitter aids with approach angle clearance, but downforce is its primary role helping achieve a 31 percent improvement.
The splitter structure creates a flat floor shape under the front portion of the bumper shape to the leading edge of the front wheels. Enclosing this area provides a significant downforce enhancement.
The splitter underside also incorporates an integral brake cooling feature, with molded shapes inspired by NACA ducts.
At the rear, the new GT500KR has a less prominent spoiler, a design to balance front-to-rear downforce variances. That's an important part of its balance and poise at speed.
"You have to experience the new KR at speed in a curve to feel the difference," Pfeiffer said. "It has an absolutely minimal aero moment of just 54 lb.-ft. at 120 mph, a 92 percent improvement versus the GT500. That is central to its confident handling ability. Because it's just as happy at 120 as it is at 60, the GT500KR is a very special performance car."
"If you drive the GT500 and new KR back to back, you might accuse Ford SVT and Shelby of sandbagging because the car feels like it has more than 40 extra horsepower," said Patterson.
"That's an effect of the aerodynamics," says Pfeiffer. "Our computer model predicts a four-tenths-of-a-second zero-to-150 acceleration effect from the aero alone. hat makes the horsepower go farther."
"We reduced the diameter of the rear sway bar for just the right grip under power coming out of a corner," said Kerry Baldori, SVT chief vehicle engineer. "That's just one example of the amount of tuning that went into engineering the KR chassis."
That tuning and the weight reduction are immediately obvious in the GT500KR's light and responsive steering. Aggressive and sticky 18-inch Goodyear tires -- 255/45 series in front, 285/40 at the rear -- are mounted on forged and polished wheels.
Powertrain calibration also makes GT500KR "street friendly" despite its performance credentials. It has a gentle, balanced feel at lo
Sources: Ford Motor Co., Automotive Industry Action Group