Engineering the Maximum Mustang GTD

Multimatic’s mad scientist, Larry Holt, fills us in on how they brought the Mustang GT3 race car to the street.

Dan Carney, Senior Editor

July 3, 2024

7 Slides

At a Glance

  • 800 horsepower
  • Inboard suspension with spool valve shock absorbers
  • Active aerodynamics with a drag reduction system like Formula 1

Ford revealed plans for the Mustang GTD last summer when it announced plans for a new peak-performance version of the veteran pony car. The 800-horsepower beast is derived from the company’s Mustang GT3 race car but is street-legal.

The car is the product of an unusual incidence of the life-imitates-art axiom. To race in the global GT3 sports car category in high-profile races like the 24 Hours of Le Mans, Ford engineers created the Mustang Dark Horse, whose high-performance components served as the foundation for race cars for both the GT3 and GT4 racing categories.

Ford turned to frequent partner Multimatic, not just for the Mustang’s sophisticated spool valve shock absorbers, but also for the design and construction of the race cars. Ford president Jim Farley, a Mustang owner and racing enthusiast, got one look at the in-progress GT3 and asked the engineering team what it would take to make the GT3 race car legal for customers to buy and drive on the street. The Mustang GTD is that car.

With this as the GTD’s back story, Ford took the occasion of the 2024 edition of the 24 Hours of Le Mans to provide the first in-person look at the GTD, with some discussion of the car by the team that created it.

As if the GTD wasn’t already sufficiently track-focused, Ford announced at the race that there will be a Performance package that adds active aerodynamics and magnesium wheels. The purpose is to deliver a Nurburgring lap time of less than 7 minutes. Unlike the rules-constrained GT3 racing category, however, the GTD is comparatively unfettered, which means it can deliver even more power than the race car.

Related:Maximum Mustang: The Mustang GTD Is an 800-hp Racer for the Street

Multimatic chief technical officer and engineering guru Larry Holt was on hand at the 24 Hours of Le Mans to supervise the GT3 racing program, which finished third in the GT3 class in the race. Before the race started, Holt spoke in Ford’s display tent in the Manufacturers’ Village at the track, outlining Multimatic’s work to turn the Dark Horse into a GT3 and to turn a GT3 into a GTD.

He started by reviewing aerodynamic work on the car.  “We’ve got a really unique wing stanchion that goes into the most structurally strong part of the car at the bottom of the C-pillar,” he said. “The [GT3] race car’s got it, so we thought that would be the way to go. The gooseneck rear [wing] mounts are the way, if you look out there on the racetrack now, everybody’s got their wing mounted to their top surface rather than the bottom. It is just a more efficient way to do it.”

But the GT3 race car must conform to rules that are designed to level the playing field across the many manufacturers with their wide variety of body styles and engine configurations. The production GTD is free to get more advanced with its management of airflow, so the team upgraded the aerodynamic systems on the car.

Related:To Le Mans in the 2024 Ford Mustang Dark Horse

If you look at that race car, it’s got a single-element wing with a fixed Gurney [flap],” Holt noted. “This is a dual-element rear wing, and that flap, that’s active. This thing generates, in its high-downforce mode, a massive amount of downforce.”

Downforce is good when you need grip for cornering, but it comes at a price. “There’s also a massive amount of drag,” he said. “So when you’re out on the autobahn, and you want to go faster than everything else that’s on the autobahn, you put it in [drag reduction system] mode and the flap flattens itself out.”

A change in downforce and drag at the rear of the car demands a corresponding change at the front, to keep the car’s grip and handling balanced.  “That would cause a problem with the front if you just did that,” Holt explained. “This [GTD] has a huge front underwing. If you look under there, it’s not flat. That’s got a big curvature underneath the front of the car. We open two flaps in there that screws that all up so it doesn’t generate quite as much downforce.”

Related:Goodyear Racing Takes on Le Mans

Multimatic made its name in racing with its dynamic spool valve shock absorbers, so naturally they devised advanced suspension for the car. “We did some radical things!” said Holt in video posted on Ford’s YouTube channel. “It’s got inboard suspension like a lot of prototype race cars. We put a transaxle gearbox in the back. A transaxle is what racecars have. Was that an easy thing to do? In a car that was never designed to have a transaxle? No! It was a smokin’ hard problem to solve.”

Back at the track in France, Holt explained some of the capabilities of that inboard suspension. “We have two ride heights for this car and two spring rates for this car,” he said, noting that the Ford GT, which Multimatic built for Ford, also featured. “When you put it in Track mode, it pulls the front down 40 [mm] and the rear down 30 [mm]. So not only do we get the center of gravity down, we also put a little rake into it, so it gives is a little bit more front [grip] so the car’s really well balanced for the track.”

The system’s capabilities go far behind adjustable ride height, though. “Then it does something else,” Hold continued. “It doubles the rear spring rate and takes the front spring rate up by 2.8 times. Now you’ve got an extremely stiff car; low, raked, big aero.”

These are the kind of technologies that can produce extremely fast lap times at race tracks, even though the GTD is a street car. Ford’s goal is to set a new benchmark time at Germany’s Nurburgring circuit with the GTD. “From the lightweight carbon fiber body on every GTD to the active aerodynamics of the Performance package, we’ve learned from motorsport how to make the Mustang GTD excel everywhere, all in the quest for a sub-seven-minute lap of the Nurburgring,” said Mustang GTD Chief Engineer Greg Goodall.”  

The company will make that attempt this summer, so stay tuned for the outcome.

About the Author(s)

Dan Carney

Senior Editor, Design News

Dan’s coverage of the auto industry over three decades has taken him to the racetracks, automotive engineering centers, vehicle simulators, wind tunnels, and crash-test labs of the world.

Sign up for the Design News Daily newsletter.

You May Also Like