5.0 Mustang & Super Fords
Castrol Syntec Top Car Challenge - Challenge Met
We Walk Tall And Carry A Really Big Supercharged Stick
On the Dyno
Dyno day was Wednesday on the Superflow chassis dyno at K&N Performance. Top Car Challenge rules allow each entry to make three pulls with five minutes to cool down between runs.
For Carlos Cortez's Shelby GT500, Technical Editor KJ Jones elected to make two runs back-to-back, then ice down the 5.4's Lysholm twin-screw supercharger and intake tract for 10 minutes, figuring the two quick runs would warm and thin the oil, then the longer cool-down would allow cooler inlet air temps.
This proved to be a great plan, as Carlo's beast ripped off two perfectly repeated 650hp passes, and followed up after the ice treatment by cranking out an additional 15 hp to post 665 ponies at the feet. Only the turbocharged Toyota Supra could come somewhat close to that figure, whining out a respectable but distinctly second-place 590 horses.
A brief cool-down immediately followed each car's power passes on the dyno, followed by a 2,500-rpm emission test. Lasting 90 seconds, the sniffer didn't encounter anything it didn't overwhelmingly like about our Shelby, despite its long-tube headers, lack of catalytic converters, and potent fuel.
On the Road
The cruise portion of the Castrol Syntec Top Car Challenge was a non-entity for Carlos' Shelby GT500. A low-mileage bolt-on car, the GT500 ran the six different freeways, surface streets, and grinding stop-and-go traffic in 100-plus-degree heat with the AC cold as ice. An on-board data logger showed the water temperature seemingly glued to 185 degrees, and mileage measured 18 mpg for the 180-mile, approximately three-hour grind.
And we should emphasize Carlos' Shelby is absolutely a street car (one heck of a street car, we might add). No rattle-trap shaker, the GT500 is a 3,700-mile cruiser devoid of squeaks or rattles. The stereo blast tunes; the stock AC is, if anything, an over-achiever; the stock seats are cushy leather; and above all, it can drop its top for open-air enjoyment.
Stop and Go
At Buttonwillow Raceway Park, the first point of business was evaluating the dragstrip performance for each 'Challenge entry. The facility uses a portable dragstrip setup (complete with staging beams, a Christmas Tree, and 60-foot and quarter-mile time and speed), which was set up on the long back straight of the relatively flat and slightly technical road-racing circuit.
Our Maximum Motorsports crew disconnected the GT500's front sway bar for better weight transfer, the tire pressures were let down in back to 18 psi, and Tech Editor Jones slid behind the wheel. Three runs were allowed, with KJ opening via a wheel-spinning 12.07-second rodeo ride. As KJ put it: "It was a little on the edge, sideways, with just a haze of the tires in Third gear."
Knowing a little softer was the answer, KJ toned down the launch and shifts, but backed up to a 12.24. As anyone with experience in high-powered, high-torque cars with stock-type suspensions can attest, a beast like this is not easy to drive. Luckily, KJ has the skills, and on the final pass managed to find what he calls "the perfect storm," which resulted in a beautiful run to 11.76 at 124 mph.
"Carlos' car pulls like a freight train," says KJ. "Without being allowed to do any type of burnout, making a good, clean dragstrip pass isn't easy in this Shelby-especially with street tires on a surface that has not been prepped in any way. I had to process everything really quickly on each pass, because before I knew it, the car had pulled right to that point where the tires were starting to spin."
Along the way, onboard timing equipment gave the 0-to-60 time at 3.9 seconds. Together, the quarter-mile and 0-to-60 runs highlighted the Shelby's muscular strength. Only the Nissan GT-R could best it, thanks to the Japanese car's combination of good power, lighter weight, and far superior all-wheel-drive traction and electronic launch control.
All brake testing was done by a designated test driver and run from 80-to-0 mph. Everyone was surprised just how well the GT500 did, perhaps because they recall last year's '94 Cobra with its unbedded brake pads and excruciatingly long stop from the same speed.
The GT500's giant Brembo brakes and Hawk HPS Plus street pads anchored the big convertible in an eyeball-popping 173 feet! That's a lot better than in 2009, and a dramatic illustration of the importance of pad bedding.