5.0 Mustang & Super Fords
2008 Ford Shelby GT500KR - Kingdom For A Horse
Ford SVT And Shelby Autos Join Forces To Create A GT500 Fit For A King's Ransom
Horse Sense: A remarkable amount of engineering went into upgrading the base GT500 to KR specs. That's a lot of work for a run of 1,571 vehicles (1,000 in the '08 model year, and 571 in the '09 model year, which equals the original run of GT500KRs). As such, I wouldn't be surprised to see some of the parts and technologies developed for this 'Stang show up on future models.
The key turns. The 5.4 roars to life. Varoom. Burble, burble. Rmmmm, rmmmm. As the car pulls away from the curb, the blower whirrs to life, singing through the air as I head down the mountain path. From the start, the GT500KR feels familiar, yet different. It's more visceral, more controlled, and of course, it costs a lot more-$79,995 to be exact. I flew all the way to Utah just to spend some time in the car and find out what makes this run of 1,000 King of the Road-spec '08 GT500s so special. Thankfully, it's much more than a few badges and stickers.
Being charged with the task of improving upon the thus-far penultimate Ford Shelby GT500 would certainly be daunting. However, it's the sort of problem-solving that keeps Ford's Special Vehicle Team engineers revved up. Of course, the most obvious flaw of the stock GT500 is its plush, plowing suspension. Certainly it offers a nice balance of ride quality and handling, but when pushed to the edge it understeers like no tomorrow. Given SVT's long history for improved handling, it's no surprise that a great deal of focus was placed on that feature for the KR.
"The KR is much more than just a great straight-line performer," says Jamal Hameedi, chief program engineer at Ford SVT. "It's the complete package-handling, power, and performance. The team put the GT500KR through rigorous testing and have witnessed slalom runs with sustained lateral acceleration of 1.0 g on the skidpad. Those are world-class numbers."
When you hear things like "1 g" and "world-class numbers," you might expect the KR to leave ride quality behind like a trail of rubber. That's not so at all. On the street, our well-calibrated hindquarters could detect only the slightest hint that the suspension was stiffer than our previous GT500 experience. However, even on our street drive, which started out hurtling down some twisty mountain roads, the upgrade in handling was readily apparent. I knew right away the car was going to be a blast on the road course, but more on that later.
While the suspension delivered guilt-free handling improvements, you'd expect that an exhaust that was strikingly louder even at idle might grate on your nerves after a while. I've had cars with similar exhausts. However, the KR gurgles at idle, snarls when you open up the twin-bore throttle body, and suddenly mellows out. In essence, its just about the perfect exhaust for my middle-aged ears, as it announces the KR's credentials when you want it to but blurs into the background when you want to cruise on the highway.
Rounding out the street-driving experience is crisper acceleration courtesy of improved tuning, a better Ford Racing cold-air induction system, and a set of 3.73 gears out back. The KR feels quicker than your smug neighbor's stock GT500, but it isn't the fastest GT500 in town. That title falls to the aftermarket versions with bigger blowers. The incremental steps in power and massive steps in handling provide a car that's even closer to achieving true balance, which would prove its worth on the road course.
It was a familiar scene for me as we rolled into Miller Motorsports Park for the road course portion of the KR program, but in a change from many other events in the past, Ford truly brought out its Steed For Every Need lineup for the press to experience. As such, I was able to drive a Mustang GT, a Shelby GT, a Bullitt, a Miller School Car, a GT500, and a GT500KR all in one day. It was an orgiastic feast of performance for a Mustang lover, and besides an enjoyable experience, it provided a much needed refresher on the personalities of all these different Mustangs. Not surprisingly, the KR was the most fun, but I really liked the Bullitt on the road course, too.
Gathering up all the willpower I have, I resisted the urge to jump in the KR and blast as many laps as I could. I really wanted to climb the ladder in order, so before driving the top dog, I made a point of driving the base GT500 first. Given that I have personal GT500 experience, it was still enlightening to drive these cars back to back. Just as I remembered, the plush factory GT500 suspension does an admirable job balancing comfort with an acceptable level of balance. Sure, it plows at the limit, but for a musclecar it does a fair job of carving corners.
You'd think moving to essentially the same car with a few improvements wouldn't be a big deal, right? The KR performed well on the street twisties and wasn't harsh-could the track improvement be that big? In short, yes. The improvement was huge, and the reason is two-fold: a new suspension and a developed-for-the-KR Goodyear tire compound. However, the results provided a near night-and-day difference in the car's handling. Where the GT500 wallows, the KR remains resolute; where the GT500 pushes, the KR turns in. Impressive stuff!
In the end, it was tough for me to give up my seat in the KR and trudge out trackside to do my photographic duty. What's tougher is knowing that only a few of these cars will ever be driven as hard as they deserve to be driven. The improvements in the appearance, exhaust, and handling made the marginal horsepower improvements a nonissue. The KR is an all-around better car. Of course, you can do a lot with a base GT500 and $40,000. For now, however, the GT500KR holds the factory Mustang crown, and it's worthy to do so.
Apparently, running the KRs down the assembly line at Auto Alliance posed a number of difficulties that led to them being converted at Shelby Automobiles. Ford and SVT made sure to bring the Shelby team up to speed on all their quality initiatives, as Ford has an impressive quality rating to uphold on the GT500. As such, the cars are shipped from AAI as unsaleable, preconversion cars that are then converted to KR specs before being shipped off to lucky new owners in an enclosed trailer.
I was lucky enough to tour the Shelby facility while some of the same cars we drove in Utah were being assembled, and I walked away quite impressed with the operation. Suffice it to say, a lot of work goes into crowning a King of the Road.
With a new calibration, exhaust, and cold-air induction coupled with 3.73 gears out back, the KR accelerates quicker than a base GT500 and is capable of 1g acceleration on a skidpad. The springs are 17 percent stiffer up front and 7 percent stiffer in the rear, and the dampers and sway bars were tuned to work in concert. The results are impressive, as the car handles much better than the base GT500 but retains great ride quality. Now the base GT500 is capable of 0.92 g, so it's no slouch, but the KR takes it up a notch, which is far enough to require the use of an axle-vent reservoir developed for the FR500C to keep fluid from blowing out during prolonged, hard cornering.
There's nothing internally different about the GT500KR's engine versus the base GT500, but it's enhanced with a Ford Racing cold-air induction kit, a more aggressive exhaust system, and a crisper calibration that combine to make the car feel quicker and sharper. Increased ignition timing and improved electronic throttle response are the major contributors. Besides the CAI, billet caps for the radiator, intercooler, power steering fluid, windshield washer fluid, and oil-fill highlight the KR engine compartment. The tag on the core support denotes the true Shelby lineage of the KR.
While the main cold-air intake system is from Ford Racing, the version on the KR features bracing to reduce expansion and contraction from heat. A seal around the mass air housing and between the box and the hood keeps hot engine air out of the inlet. All told, the hood and cold-air intake are said to reduce the base GT500's 37-degree inlet temp increase over ambient by 5 degrees.
A work of art, the carbon-fiber KR hood is Ford's first use of carbon fiber in a production car. It's made up of more than 100 pieces of carbon fiber that are molded together in an autoclave to create a dual-zone pressure management system. Not only does it look great, but the scoops are functional, forcing ambient air into the airbox. Likewise, the rear vents function by letting pressure and heat out of the engine compartment while channeling water away from engine electronics. The hood, along with the exhaust system, contributes to a 22-pound reduction in curb weight versus the base GT500. The hood's outer panel is only 1.2 mm thick, while the inner panel measures only 0.8 mm and is 11 pounds lighter than the base car's aluminum hood.
Besides the way-cool 5.0&SF license plate, the centered Shelby lettering and V-6-style wing are sure signs you've approached a KR. The most telling sign, however, is the raspy rumble of the KR exhaust system which features an H-pipe instead of the X-shape crossover on the base GT500 along with the smaller, cylinder-shaped mufflers from the Bullitt Mustang. Since Shelby Automobiles is the manufacturer of record on the KR, the exhaust-noise standards were more flexible than those of a typical production-line Ford.
At first glance, there isn't much to distinguish the KR from the base GT500's interior other than the cue-ball shifter poking up through the center console. There's also a plaque on the dash and GT500KR stitching on the headrest. The shifter, however, contributes to the high-performance feel of the KR with shift throws that are 10.5 mm shorter than the factory version. The KR unit is actually a revised version of the Ford Racing shifter, which features slightly softer bushings to keep the noise, vibration, and harshness levels within factory specs.
|5.0 Tech Specs|
|ENGINE AND DRIVETRAIN||Transmission|
|Block||Tremec T-6060 six-speed|
|Stroke||8.8 w/ 3.73 gears|
|Crankshaft||Spanish Oak PCM|
|Rods||Coil on plug|
|Cracked forged-steel I-beam||Gauges|
|Pistons||SVT silver-face gauges w/ MyColor|
|Compression Ratio||SUSPENSION AND CHASSIS|
|Camshafts||Reverse L independent|
|DOHC||MacPherson strut w/ 34mm|
|Intake||14-in discs w/four-piston Brembo|
|Cast-aluminum w/ air-to-water||calipers|
|Power Adder||18-in Alcoa forged|
|Eaton hybrid Roots supercharger||Tires|
|Throttle Body||Goodyear F1 P255/45-ZR18|
|Electronically actuated dual 60mm||Rear Suspension|
|Mass Air||Three-link solid axle w/ coil|
|90mm||springs, Panhard rod, and 24mm|
|Fuel Pump||11.8-in discs w/ TRW one-piston|
|Dual pumps, 375-lph||calipers|
|Cast-iron manifolds||18-in Alcoa, forged|
|Stainless steel H-pipe w/||Goodyear F1 P285/40-ZR18|
|cylindrical resonators|| |