For 2007, Ford's Special Vehicle Team launched the highly anticipated Shelby GT500, successor to the 2003/2004 Mustang SVT Cobra. The GT500 shares many of its basic design characteristics with that of the Mustang V6 and GT. In particular, the GT500 retains the same basic live axle rear suspension setup of the Mustang V6 and GT, though with some minor durability enhancements to handle the car's greater power. Thicker sheetmetal supports and extra welds can be found on the GT500 chassis as well as redesigned strut towers to accommodate a wider engine. A supercharged 5.4 L 32-valve DOHC V8 with an iron block and aluminum heads powers the GT500. The engine is mated to a Tremec TR6060 6-speed manual transmission and is rated to produce 500 hp (373 kW) @ 6000 rpm and 480 lb·ft (650 N·m) of torque @ 4500 rpm. A final drive ratio of 3.31:1 is standard in the GT500. Also standard are 18x9.5 inch wheels with P255/45ZR18 tires in the front and P285/40ZR18 tires in the rear. Stopping power is provided by Brembo 14-inch disc brakes with aluminum four-piston calipers in the front and 11.8-inch disc brakes with two-piston calipers in the rear. [13]
In spite of its high end features and strong performance, the GT500 failed to meet some automotive journalist's expectations[14][15]. Car and Driver magazine, for example, though praising the GT500 for its ample horsepower and relatively smooth ride, criticized their test car for its heavy weight and, in particular, the nose-heavy weight distribution of 57.7% front and 42.3% rear (compared to the 52.5% front, 47.5% rear of a Mustang GT manual they tested).[16] Nevertheless, in spite of their opinion on its drawbacks, Car and Driver drove a GT500 in their 2007 "Lightning Lap" road test and found that the car's on-track performance fell between that of theAudi RS4 and the BMW 335i with a lap time of 3:11.0 at Virginia International Raceway. [17].
Shelby GT500KR
Building on the high performance foundation of GT500, engineers from Ford SVT and Shelby Automobiles sought to build an even more powerful car: the Shelby GT500KR. Debuting as a 2008 model, the GT500KR, "KR" being an abbreviation for "King of the Road", pays homage to the original 1968 Shelby Mustang of the same name. To back up its name, the GT500KR features a host of new components and performance enhancements over a standard GT500. Under the hood, the GT500KR uses the same supercharged 5.4 L DOHC V8 as the standard GT500, but the KR's engine has been tuned to make 540 hp (403 kW) @ 6250 rpm and 510 lb·ft (691 N·m) of torque @ 4500 rpm, gains of 40 hp and 30 lb·ft of torque, respectively. While the Tremec TR6060 6-speed manual transmission remains the same, the GT500KR also benefits from a more aggressive 3.73:1 final drive ratio. To improve handling and help offset the car's front-heavy weight distribution, the GT500KR features a Ford Racing strut tower brace and uniquely tuned struts, shocks, and springs. Finally, to maximize the GT500KR's performance gains, measures were taken to keep the car's weight in check. Through the use of things like a carbon fiber hood and a revised exhaust system, the overall weight of the GT500KR is actually 22lbs lighter than a standard GT500.[18] For all of its performance enhancements and exclusivity as a limited production car, the GT500KR launched with a significant MSRP of $79,995.
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