Aston Martin Brings Big V-12 Noise to Saturday’s 12 Hours of Sebring

There are several “firsts” that the Aston Martin Valkyrie brings to IMSA and to Saturday’s Mobil 1 Twelve Hours of Sebring sportscar race, but the big headline is its naturally-aspirated V-12 and its very welcome wail. It’s the first such engine to appear in this modern era of the GTP/Hypercar prototypes, which only began in 2023. The last V-12 prototype to race at Sebring was also an Aston Martin—Greg Pickett’s Muscle Milk car in 2011, when the American Le Mans Series sanctioned the race.

“With its unique sound from the V-12, 6.5-liter engine, I am certain this car will win the hearts and minds of American racing fans,” said Adam Carter, head of the endurance program at Aston Martin. The Valkyrie that was tested at Daytona International Speedway in November, which we attended, was quieter, though it had more horsepower than the Valkyrie at Sebring.

The Daytona car was running a more aggressive silencer—IMSA has since approved a louder one—and for Sebring, IMSA used its playfield-leveling “Balance of Performance” modifications to cut the V-12 by 15 horsepower, to 683, while allowing the car to shed 26 pounds. That vast majority of that horsepower trim comes at what IMSA calls “V1” speeds—from 0 to 143 mph.

Even so, IMSA President John Doonan calls the Valkyrie’s sound “magical,” making IMSA just that much more diverse. “You’ve got a ground-pounding [naturally-aspirated] V-8 in the Cadillac, the sweet sound of an Acura [twin-turbo V-6], and a BMW and a Porsche, all turbocharged V-8s, then of course the Lamborghini’s twin-turbo V-8, but what the Aston brings to me is this sound that appeals to those of us who’ve been around the sport for a long time. We’ve heard that noise, and now it’s coming back.”

Other innovations the Aston Martin Valkyrie brings to IMSA: Aston said it is the first entry into the GTP and Hypercar class—we’ll explain those in a moment—to be “derived from a road-legal car.” That vehicle shares the Valkyrie name with the racecar, and it was designed by former Red Bull Racing Chief Technical Officer Adrian Newey. With gas and hybrid power, it pumps out a combined 1139 horsepower. The price for Valkyries in 2022 was $2.4 million, and it’s gone up by a million since then.

As for GTP and Hypercar: The top class in IMSA is called GTP, and in the Europe-based World Endurance Championship (and at the 24 Hours of Le Mans), the top class is called Hypercar. The cars are very similar, but not identical. Hypercars are built to a ruleset called LMH, and IMSA cars are built to LMDh specifications. The term hypercar is also widely and loosely used in Europe to describe most any street-legal supercar.

LMH cars are designed, from the ground up, by the manufacturers who race them or their agents. Both cars have gas-powered engines and relatively mild hybrid systems, but LMH cars are allowed to compete without any hybrid equipment except, in this case for the Valkyrie, for a small battery that allows them to enter and leave the pits on electric power. Otherwise, Aston chose to make the racing Valkyrie gasoline-only, rear-wheel-drive.

LMDh cars must use a hybrid system that IMSA specifies, and all power goes to the rear wheels. Also, while LMH manufacturers can design their own chassis, builders of LMDh cars have to pick an approved chassis from Multimatic, Dallara, Oreca or Ligier, and all use an approved one-source gearbox, battery and hybrid controller. Aston Martin collaborated with Multimatic to develop its chassis.

Obviously, you can cross over and run LMH-spec cars in IMSA, and LMDh-spec cars in the WEC and Le Mans. But using that Balance of Performance, expect both series to either speed up or slow down individual manufacturers in the name of relative competitive parity. Building an LMH car just allows the manufacturers a little more freedom than LMDh does.

Longtime IMSA competitor The Heart of Racing has been running Aston Martin GT cars since 2020, and they were tapped to head the LMH program for both the IMSA and WEC—a two-car team in WEC (that’s mandated there) and, for now, a one-car team in IMSA.

Drivers of the Sebring entry will be Roman De Angelis, the 2022 IMSA GTD champion, and Ross Gunn, who has won races in the GTD and GTD Pro categories, both of whom will be in this number 23 Valkyrie for the remainder of IMSA’s season. This week at Sebring, and then again at the season-ending Petit Le Mans at Michelin Raceway Road Atlanta, they will be joined by Alex Riberas, a regular Valkyrie driver in the WEC, because his races there don’t conflict with Sebring and Petit.

“I think it’s going to be a huge challenge both physically and mentally because Sebring is always one of the toughest. But it’s what we have trained hard for,” Gunn said.

The Valkyrie made its race debut in the 318-lap WEC event in Qatar on February 28. Aston Martin entered two cars: Number 007, in which Gunn was a driver, completed 181 laps, finishing 32nd in the 36-car field. De Angelis and Riberas were in number 009, which completed 295 laps, coming in 17th in the group of 18 Hypercars, which were also fielded by Ferrari, BMW, Toyota, Cadillac, Peugeot, Porsche, Alpine, Proton and Cadillac.

At present, Ferrari, Peugeot, Alpine, and Toyota don’t race here in IMSA. Acura and Lamborghini race here, but not there. Ford will join in both series—WEC in 2027, and IMSA in 2027 or 2028. Proton is a privateer team that competes in both series in a Porsche.

The stated goal for Aston Martin this weekend is to finish. That would give them some valuable data to take to the 24 Hours of Le Mans in May, a critically important race for manufacturers. While Sebring is just half as long as Daytona or Le Mans, those two races are run on comparatively smooth tracks, and the rough-as-a-cob Sebring, especially given its frantic pace, can show teams what their weaknesses are.

“One thing everyone knows about Sebring is that it’s very challenging,” said Riberas. “We know we are stepping into a big, big weekend for everybody.”

Sebring follows January’s season-opening IMSA WeatherTech SportsCar Championship race, the Rolex 24 at Daytona, where the Penske Porsche 963 took first and third place, with a Meyer Shank Acura ARX-06 in second. As at Daytona, the LMP2 class will race—those are also built-from-scratch prototypes, but all the teams must use the same spec engine and a spec chassis, and they look a great deal like the premiere GTP-class cars.

There are also two GT classes running—those are cars that start with a recognizable road-going model. The GTD Pro class allows the use of a driver roster that IMSA considers to be full-time professionals, while the GTD class allows the use of one pro, teamed with two amateur-level drivers. The cars in GTD and GTD Pro are the same—Aston has two entries there, based on the Vantage V-8 sports car, and there are also cars from Ferrari, Porsche, Lexus, BMW, Mercedes-AMG, Lamborghini, Chevrolet Corvettes and Ford Mustangs.

In all, there are 56 entries for Sebring: 13 GTP cars (including the Aston Valkyrie Hypercar), 12 LMP2 cars, 11 GTD Pro cars, and 20 GTD cars.

The 73rd Mobil 1 Twelve Hours of Sebring takes the green flag at 10:10 a.m. Saturday. As for watching it on TV: For this race, you must have Peacock Premium, where it airs live from 10 a.m. to 10.30 p.m. The race streams free on IMSA.tv and on IMSA’s YouTube channel, but those are blocked unless you are outside the U.S. The race will also be broadcast on IMSA radio, available at IMSA.com, or on Sirius/XM channel 206.