Carl Widmann, the chief engineer at Ford Performance, gave us the lowdown on the new, 700-plus-hp Shelby Mustang in Detroit.
The last iteration of the Shelby GT500 impressed with its 662 horsepower, but—and I hope you’ll excuse the pun—it was a bit of a one trick pony. Absurdly quick in a straight line, but its handling was compromised by the limitations of the previous Mustang platform, which still used a solid rear axle. It wasn’t the Mustang you’d take on a road course.
The new GT500 still has big horsepower from a supercharged V8—over 700 hp, Ford promises—but it’s designed to handle, too. Put another way, Ford wants this to go up to a Challenger Hellcat on the drag strip and against a Camaro ZL1 1LE on the track.
“If we were going to make the GT500 the pinnacle of the Mustang now, it has to do both. There’s just no question,” Carl Widmann, chief engineer at Ford Performance told me. “We have so much capability out of the GT350 and all the Performance Packs and the base Mustang lineup. To be that pinnacle or the halo for any Mustang, it had to have that capability.”
Widmann gave us lots of the engineering details on this seemingly remarkable machine just after the cover was pulled off at the North American International Auto Show in Detroit this week.
The engine shares its 5.2-liter displacement with the naturally aspirated Voodoo engine in the GT350, but there are quite a few differences.
“We knew we wanted the 5.2-liter block out of the GT350,” Widmann said. “The trick was we had to really modify it to take all the boost that comes off that 2.6-liter Eaton supercharger.”
Consequently, the Voodoo block got new, longer bolts for the cylinder heads, new gaskets, additional cooling passages, and different seals. The cylinder heads themselves are modified to deal with the additional heat and pressure, too.
What makes the Voodoo unique (and beloved) is its flat-plane crankshaft. Flat-plane V8s have a different firing order than traditional cross-planes, giving them a unique sound, and they generally tend to rev higher, since the crankshaft itself is lighter. The Voodoo spins up to 8250 rpm and sounds downright evil.
The GT500 engine gets a more-traditional cross-plane crankshaft. “You don’t really need it,” Widmann said. “Because you’ve got such a short runner off the supercharger. . . you don’t get a benefit going to a flat plane.”
That Eaton supercharger pumps out 12psi of boost, and its intercooler is tucked into the valley between the cylinder banks to help keep the center of gravity low.
So, while Ford used the Voodoo as a starting point for this engine design, it’s ended up quite a bit different. Widmann did, however, tell us that the GT500’s block will actually make it into the GT350 once it’s in production.
Of course, what this V8 is bolted to is a big story, too. For the first time in a Mustang, there’s a dual-clutch gearbox, a seven-speed unit sourced from Tremec. Ford Performance opted for a dual-clutch for its high torque-handling capability and because it can shift a lot quicker than a torque-converter automatic, to say nothing of a traditional three-pedal manual. Widmann didn’t rule out the possibility of a manual in the future if there’s sufficient demand, but it’s not part of the plan currently.
Power gets to the rear wheels from the DCT via a carbon-fiber driveshaft and a Torsen limited-slip differential.
Keeping all these drivetrain components cool during long lapping sessions on track is paramount, which is why the GT500’s frontal opening is twice as big as a GT350’s. There are eight heat exchangers—two for the engine, two for the supercharger, one for the transmission, one for the engine oil, one for the rear axle, and, of course, an AC condenser.
Having a big open front fascia isn’t always ideal for aerodynamic efficiency, though. Generating downforce and reducing lift was a big development goal with the GT500, so these cooling requirements complicated matters. “The thermo aero-systems engineers pulled a lot of hours on the computational dynamics,” Widmann said.
Ford will offer a few aero configurations for the GT500 on top of the standard car. Opting for the Handling Package brings a Gurney flap for the rear wing, while the Carbon Fiber Track package adds a two-way adjustable wing similar to that used on the Mustang GT4 race car and removable splitter wickers with dive planes at the front. The vent on the hood is the largest in any Ford ever, and there’s an aluminum rain tray underneath that, when removed, further reduces under-hood pressure.
“What we’ve done is provided more customization on the track for different purchasers,” Widmann said. “It’s got a little bit more flexibility to set it up the way you want.”
Of course, increasing aerodynamic grip wasn’t the only development priority with the GT500. Ford wanted it to be faster than the GT350 on a road course, so upping mechanical grip was essential, especially when you’re dealing with over 700 hp.
The GT350 uses 19-inch wheels, but Ford went to 20-inchers on the GT500 to get more tire onto the ground. This necessitated some changes in suspension geometry and tuning from the GT350. As standard, you get Michelin Pilot Sport 4S tires, which Widmann said offer a good balance between road and track performance, but opting for the Carbon Fiber package nets grippier Michelin Pilot Sport Cup 2s.
You also get carbon-fiber wheels with that package. They’re sourced from the same Australian company that makes the wheels for the GT350R, Carbon Revolution, only they now have an exposed weave and a glossy finish to show it off. And despite increasing in size, the GT500’s carbon-fiber 20s weigh just about the same as the GT350R’s 19s—around 18 pounds. These wheels help save around 60 pounds in unsprung weight, which will pay dividends in ride, handling and braking.
Widmann said that you might not be able to discern much of a difference between the carbon fiber wheels and the standard alloys on the street, but at the track, the improvement should be noticeable. The rear carbon-fiber wheels are also a half-inch wider than the standard alloys.
Going for bigger wheels meant that Ford Performance could fit bigger brakes—there are 16.5-inch two-piece steel rotors with six-piston calipers up front and 14.6-inch rotors with four-piston calipers out back.
Initially, we thought the GT500 might get the Multimatic DSSV shocks used on the Ford GT (and Camaro ZL1 1LE), but Ford Performance went with MagneRide instead, like those used on the GT350. Widmann said the MagneRide shocks allow for around 1000 adjustments per second, plus, they can communicate with the car’s powertrain and braking systems. This allows for different damping characteristics based on drive modes, and one assumes, more comfort on the street. The GT500 also gets bigger sway bars and stiffer springs than the GT350, while opting for the Handling or Carbon Fiber Track packages brings adjustable top mounts, too.
The GT500 also gets unique programming for its drive modes, too, with changes in ABS, traction control and engine and transmission mapping for different scenarios.
We had to ask about the headlights, too, since they’re actually from the pre-facelift Mustang. Widmann said they help keep the two Shelbys similar in appearance, and they’re actually somewhat lighter than the newer headlights.
There’s a lot we don’t know about the GT500 yet. Horsepower and torque numbers aren’t finalized, and weight and performance figures are still up in the air. All Ford has said is that the GT500 offers over 700 hp, runs 0-60 mph in the mid-three-second range, and should run a sub-11-second quarter-mile.
But given what we know about the engineering that went into this car, we know it’s going to be damn impressive. The GT350 is already one of the all-time great Mustangs, and it seems like the GT500 just takes up everything a notch. We can’t wait to find out.