5.0 Mustang & Super FordsCar Reviews
2007 Shelby GT 500 - Test Drive
Ford SVT restomods the S197 Mustang to create a Shelby GT 500 musclecar for a new generation
Horse Sense: Along the way to getting thestory on the GT 500, we picked up a few hints about the next refresh onthe Mustang. It's apparently "well underway," and it looks to add a moredefined character to the car, especially on its currentlyextrusion-smooth flanks. This next iteration was also described as "verymodern," so perhaps it's a move away from pure retro to a modernprimitive look like the Camaro concept, which is sure to hit around thesame time the Mustang is freshened. Gotta love competition.
Anticipation could not have been higher. Ford has been teasing us withshow cars for so long we almost couldn't believe it when the invitationcame along to drive the real thing. Sure, our own Tom Wilson drove anearly engineering car months ago, but these cars promised to be muchcloser to the production version, though Job 1 isn't scheduled till thissummer. As I rounded the corner at California Speedway in Fontana,California, there they were--practically every Shelby GT 500 prototype inexistence and even the man himself, Carroll Shelby, stood watch wearingall black.
These cars really do exist! Somewhere between 7,500 and 8,000 luckyMustang performance enthusiasts will be able to buy a 500 hp,supercharged, 5.4 Mustang bearing the name of the most famous Mustangtuner ever. Better yet, the car is largely the product of Ford's SpecialVehicle Team, which has long produced some of our favorite vehicles.Because the media program was hosting a larger group of scribes andthere were few cars--we only drove two on the road course inside CalSpeedway--I had to wait for the first group to have its way with thecars while I scoped out the little details.
If you're one of the many in line to buy a Shelby GT 500, it's likelyfor the same virtues on which SVT was founded: performance, exclusivity,and value. At a projected $41,950 sticker (includes destination and delivery charges) for a base coupe, the GT500 is an incredible value. Of course, if you want one right away,you'll have to be willing to pay an early adopter tax that we've seenrange from $5,000 to $25,000 over MSRP. That kind of capitalism,combined with the car's horsepower ratings, has pushed the car intounfair comparisons with the much lighter, much pricier Corvette. Well,the Mustang has never been and never will be a Corvette. You can't takeyour wife and kids out for ice cream in a Corvette. But you'll likely beable to outdo a Corvette at the drags, and by the time the initialfrenzy dies down, you can do it for the kind of price that makes thiscar such a performance value. Ford is committed to building 8,000 to10,000 GT 500s per year for three years. So if you're patient, you mightjust be able to buy the most powerful Mustang ever built.
Our group finally made its way to the track. I grabbed a helmet andjumped in line. I took the second car, a Tungsten Gray coupe with SatinSilver stripes, which just happen to be the colors I would want. Afteradjusting my seating position and getting settled, the interior feltquite familiar to anyone who has driven an S197 Mustang, but thepresentation is a bit more upscale. As I pulled away down the accessroad, I immediately noticed two things. The clutch pedal effort was justa notch more than a GT's and much less than a Terminator's, which issurprising for a car with more power. According to the SVT engineers,the clutch in the GT 500 is a metalliceramic unit sourced from theFR500C racer, but the effort is indeed reduced by 17 pounds (33 versus50 in the Terminator).
I noted the cars seemed really quiet while other cars lapped the track,and only a bit raucous when throttled from a standing start. Theserenity is even more pronounced inside the car. Exhaust and blowernoise are minimized, even with the pedal to the carpet. I'm alwaysconservative at drive programs, as I don't want to be the guy who wrecksthe car, but even as I gained confidence and began carrying more speedon track, it didn't feel as fast as I had imagined. Sure I'm probably asjaded as the come. I've driven more than my fair share of cars with 400and 500 hp at the rear wheels, but few have tipped the scales at 3,920pounds. I chalked it up to a heat-soaked blower and my unrealisticexpectations.
It was the handling that exceeded my expectations, though it reallyshouldn't be a big surprise. SVT has a history of making mammoth rides,such as the Lightning pickup that handles like much smaller vehicles.With all the improvements in the S197 chassis and a few more weldedseams, strengthened panels, and both shock tower and lateralfront-crossmember braces, the '07 Mustangs are even more robust. Allupgrades but the braces will make it to all '07 Mustangs, while thelateral crossmember brace will make it to all convertibles. Obviously,SVT spent considerable time striking a balance between road-course gripand street civility.
After getting used to the entertaining Cal Speedway course, I beganpressing a little harder and the car felt amazingly light on its feet.If you didn't set up the corners correctly it would plow like a farmtractor, but with even my modest competency the GT 500 did as it wastold. Even if I made a bad move, it cut me some slack to get my acttogether before giving up the traction. Perhaps even more impressivewere the brakes. The big Brembos did the trick without being obvious ornoisy. They were just right. And, unlike the brake setups at some driveevents I've attended, these cars reportedly did their thing with stockbrake pads, which were engineered for worry-free, open-track fun. Mucheffort was put into coming up with a pad that was quiet on the streetbut livable at a track event. We tip our hats to the braking engineerson this program, as they took what Ford learned on the FR500C Grand Amracers and made it streetable.
In short, the GT 500 was a good time on the road course, and I'm sureowners are going to have a blast at open-track events. But how was it onthe street? Well, after an afternoon of on-track bliss, Ford moved theGT 500 party to Northern California, where we'd finally get to driveamong the general public as the car was meant to be driven. Our routecontained a mixture of freeways and winding back roads. Cars werelimited, but we had more to choose from than just two. With the pressswarming to get into the Torch Red/Performance White and PerformanceWhite/Vista Blue coupes, I ended up sharing a Tungsten Gray convertiblewith old friend Tom Wilson who was there to do the deed for Road &Track.
Initially, it was too cool to drop the top. Tom took the wheel first,and had me grabbing for the door handle and pressing the invisible brakepedal on the passenger side as we barreled down the still-wet windingroads. Again, the car just didn't feel as if it had 500, but theconvertible weighs 4,040 before adding two magazine writers who hadtaken advantage of all the food made available by FoMoCo. I had towrestle control of the car away from Tom somewhere near the midpoint ofthe drive. We swapped seats; I jumped in and immediately dropped thehammer and found the rev limiter--where I'm not sure, as I was busywatching the road. That was more like it. It's always better from thedriver seat, and that familiar surge of torque followed by a steadyswell to the top of the tach felt great. With the top down at thatpoint, the blower announced itself with a bit more authority.
Without having to pay strict attention to high-speed turns, I couldinspect the little details more closely. The shifter is still a dampnoodle, but when changing gears it's definitely more precise in itsactuation. Even when shifted in anger, it seemed to provide easy gearchanges. This new TR-6060 is not your Terminator's T56. In addition tobuilding a six-speed to fit the latest Mustang, the transmissionreceived numerous upgrades, such that Tremec considers it a next-gentransmission.
Six Is Enough
So you might be wondering exactly how a Tremec TR-6060 compares with theT56 you know and love. In short, it's better in just about every way. Itcan handle more torque thanks to a move from a 10-spline input shaft toa 26-spline unit. Moreover, the new case is stronger, the countershaftsare one-piece units, and the gear faces are wider. All these changes add up tomuch greater strength, which we'll all appreciate after we start moddingthese cars. What we noticed while driving the car, however, was itseasy, precise shifting despite the factory shifter.
The prime movers in the better shifting are increased synchronizers onall the gears. Where the Terminator T56 had only two synchros on the 1-2and 3-4 shifts and single synchros on the remaining gears, the TR-6060offers triple synchros on the 1-2 and 3-4, and dual synchros on allremaining gears, including Reverse. Plus, the synchronizers have beenupgraded from a carbon-particle paper to a sintered-bronze material.
So this transmission shifts easier, but it also offers a shorter shiftthrow. "The synchronizer hubs are much narrower, reducing fore and aftshift travel," Tremec's Jim Averill explained. "Additionally, the hubsystem uses three encapsulated ball-and-coil-spring struts that are muchmore precise than the old-style hoop-and-stamped strut. This also addsto a smoother fore, aft shift."
So the TR-6060 is smoother, stronger, and just better than itspredecessors. That's cool, but the better news for those who aren'tbuying GT 500s is that Tremec will be rolling a lot of this technologyinto its aftermarket transmissions, so you'll be able to put all thegood stuff in your Mustang soon.
Again, the clutch-pedal effort shined on the street, and the silver-facegauges proved far more readable than the stock GT fare. But one quandaryI had, mainly because I never got to drive the coupe on the street, wasthe car's ride quality. Unless the convertible was on glass-smoothasphalt, it communicated every little imperfection in the pavement, andthe rear axle seemed to get upset easily. I'll admit the letters I... R...S... briefly flashed through my mind before I quickly beat them back withthe words heavier, more expensive, and wheelhop. I was left to wonder ifthe chassis upset was due to flex introduced by the lack of a roof or ifthe higher spring rates in the coupe delivered the same result.Anecdotal reports from my colleagues confirmed the coupe was definitelyfaster and had better ride quality, so that just reaffirmed to me thatI'm not a convertible guy.
So what's the verdict? Should you still lust after a GT 500? Well, I do.Yes the car is heavy--the coupe is 254 pounds greater than its Terminatorpredecessor--but it handles and brakes well. It wasn't the out-and-outanimal that I had expected: I wanted to be scared, but SVT does"balanced," so power doesn't always come to the forefront when thesecars are stock. I attribute this partly to the weight, but also to thecar's sophistication. Exhaust rumble and blower whine are banished, andI can't help but feel as though the Silver Oak tuning softens whatshould be a greater hit of torque from the bottom to the midrange. The'07 Shelby GT 500 is still a Mustang, however, and the Mustang has longbeen the best basis for a project car that money can buy. Once the GT500 hits the streets and gets just a small taste of what the aftermarkethas to offer, it will regain the true snarl and grunt of a musclecar. Iplaced my order, have you?
While I had high expectations for the GT 500 borne of too much time infast Mustangs, I'm also a compulsive tinker. The moment I decide to buya new car (or computer, gadget, or otherwise), I start locking in on allthe modifications I want to make as soon as I get it. I wouldn't evendrive my SVT Focus until I had it just the way I wanted it. Of course Idetermined I wanted a Shelby from the moment I saw it in person, despitenot knowing how I'd pay for it. From that moment I began plotting themodifications. Now that I've experienced the production car, I have afew more.
I know I'd rather have the look of the show car's hood and Shelby trunklettering. While showing us one thing and giving us another only createsnew products for the aftermarket to sell, it's just a wee bitdisappointing. Likewise, I applaud that Ford is finally offering asatellite radio option in the Mustang. Thank goodness. But I firmlybelieve iPod integration and navigation should at least be options. Forthat reason, I want to install a Pioneer AVIC-Z1 in my Shelby. It doesnavigation, XM NavTraffic that routes you around traffic with the nav,the option for either SatRad company, and the option for iPodintegration. In short, it does it all.
While inside, I think I'd upgrade the seats, as they aren't that muchdifferent from the GT seats. I know Ford is trying to build anaffordable car, so I don't fault them, but something like Recaro'sMagnifica covered in the factory Charcoal Black leather and accompaniedby a matched Recaro child seat for my son should do the trick.
As for the parts you guys care about, the recipe is already there fromthe Terminators. Adding a cold air-intake, short-tube headers, anafter-cat exhaust, a pulley, and, perhaps most importantly, a tune willturn the nice-guy Shelby into a neighborhood bully. I just hope therumors of a 600hp limit on the stock rods prove conservative, as thesecars should reach 600 hp to the tire in a hurry. The engineers said thecars were putting down mid-400hp numbers at the rear wheels withapproximately a 12-percent drivetrain loss, which sounds like more than500 at the flywheel to me.
Beyond that, I'll just tint the windows to keep out the Florida sun andhave Auto Paint Guard install and 3M Clear Auto Bra to protect theTungsten Gray paint and Satin Silver stripes. Ah, a guy can dream,right?
Say "Eaton Roots blower" and fond memories of being g-forced back into the seats of Terminator Cobras will immediately spring to mind, followed shortly thereafter by similar reminiscence of force-fed Lightning and Harley pickups. Farther back in the memory banks are the blown V-6 T-birds and Cougars of the late '80s and early '90s.
Each one of these Ford factory applications of Eaton-manufactured intercooled, positive-displacement supercharging has been a hit with enthusiasts, and we can safely predict the M122H sitting proudly atop the GT 500's fearsome 5.4 will continue this torquey tradition. In our initial look at the new Cobra (July '05, p. 54) we mistakenly said the GT 500 would have a screw blower. Well, it won't; but it will have the M122H, or what Eaton refers to as a hybrid-thus explaining the "H" in its designation. It's a hybrid of the fifth-generation Roots design as used on the Terminator and a patented, all-new sixth-generation that won't debut until 2008. It's still a Roots-unlike a screw blower, all air compression will take place in the manifold and not within the blower itself.
So why all the excitement? Efficiency. Both mechanically and thermally, the hybrid is substantially more efficient than its Gen V predecessors-thanks to reengineered rotor and port designs-and the GT 500 is the first production application of this hybrid design. The full Gen VI Roots, when it eventually comes along, will be even more efficient as it will have an optimized center-to-center distance between rotors, also known as "pitch spacing." In the meantime, the hybrid essentially combines Gen VI rotor and port designs with existing Gen V pitch diameter, or rotor spacing. In even more basic terms, think of it as Gen VI rotors in a Gen V housing.
According to Eaton, thermal efficiency is up by about 15 percent over the Gen V, meaning substantially lower blower-discharge temps. Lower air-charge temps offer less chance of detonation, permitting more spark advance to be dialed in. More advance equates to more power. And because the hybrid is also more mechanically efficient with fewer parasitic losses than its older Gen V siblings, it consumes less horsepower to generate boost. Are you detecting a pattern here?
Eaton's engineering and product strategy manager for Air Induction and Cylinder Head Systems, Craig Sell, nicely sums up the hybrid in fewer words than it takes to describe his title: "Turbo efficiency from a Roots blower." Sounds good to us- by Dale Amy
5.0 Tech Specs
Engine and Drivetrain: Iron 5.4
Bore and Stroke: 3.552x4.165 in
Displacement: 330 ci
Rotating Assembly: Forged-steel crankshaft, cracked forged-steel I-beamrods, and forged-aluminum pistons
Compression Ratio: 8.4:1
Cams: 0.394-in intake and exhaust lift with 184-deg duration (at 0.050)on the intake and 194-deg (at 0.050) on the exhaust (carryover from'03-'04 Cobra)
Heads: Four-Valve DOHC with 37mm intake and 32mm exhaust valves
Intake: Aluminum lower with integral air-to-water intercooler
Supercharger: Eaton M122H Roots
Throttle Body: Dual 60mm
Fuel System: Returnless with twin 220-lph fuel pumps and 47-lb/hr fuelinjectors
Exhaust: Cast-iron manifolds, twin cats, X-shape crossover, and dualmufflers
Transmission: Tremec TR-6060 six-speed transmission (ratios: 2.97 First,1.78 Second, 1.3 Third, 1.0 Fourth, 0.80 Fifth, and 0.63 Sixth)
Driveshaft: Two-piece aluminum
Rearend: 8.8 with Traction-Lok and 3.31 gears
Engine Management: Silver Oak PCM
Ignition: Coil-on plug
Gauges: SVT-logo'd electroluminescent with silver faces
Suspension and Chassis
Front Suspension: Reverse-L independent MacPherson strut with 34mmstabilizer bar
Springs: Coupe: 34 N/mm; Convertible: 31 N/mm
Brakes: 14-in Brembo vented discs with four-piston calipers
Tires: Goodyear Eagle F1 255/45ZR18
Rear Suspension: Three-link solid axle with coil springs, Panhard bar,and 24mm stabilizer bar
Springs: Coupe: 28 N/mm; Convertible: 23.9 N/mm rear
Brakes: 11.8-in vented discs with two-piston calipers
Tires: Goodyear Eagle F1 285/40ZR18