When a new supercar arrives, the motor gets the glory. Which is as it should be—anytime an automaker throws big money into designing an exotic space frame and 200-mile-per-hour bodywork, it needs muscle to match. The wrong engine, meanwhile, can sink a supercar's reception and reputation (look at the Jaguar XJ220 for a lesson in how a whole car suffers if it's got a weak heart).
Aston Martin can't be accused of skimping on the heart of its new halo car, the $3.2 million out-of-this-world . The new supercar's motor spins out 1,000 horsepower on its way to an 11,100-rpm red line, the highest yet seen in a road car. And this monster is all motor, no turbos or superchargers to be found.
“It was clear from the beginning that it was going to be a clean-sheet, bespoke design,” says Bruce Wood, technical director of Cosworth.
Indeed, no engine in production could meet the specifications Aston laid out for the Valkyrie, so the automaker hired Cosworth, the famous British engineering firm that specializes in high-performance and racing engines, to build one from scratch.
We live in an era when even econoboxes and pickup trucks have turbos, and not for nothing. “It's very hard to find a reason not to use forced induction in 99 percent of road vehicles,” Wood says. But Cosworth and Aston Martin saw the Valkyrie as part of the 1 percent.
Even with today's top turbo tech, including the lowest-lag systems designed to mitigate the delay between pressing the throttle pedal and receiving the turbo's extra power, there remains some lag as the turbo spools up. “[The Valkyrie's] only job was to be the greatest driver's car ever created,” he says. “It had this purity of purpose which set it apart, and…for such a driver's car, it was always going to be naturally aspirated.”
And with that four-figure horsepower number, is the Valkyrie in a club with cars like the Bugatti Chiron? Aston Martin wanted "only" 950 horsepower out of the engine, Wood says. But when Cosworth tested the prototype, they found it produced more oomph than they'd expected.
As for the V-12 configuration, that was born of pure math. Once an engine builder sets a power target that high, an engine homes in on a 6.5-liter capacity, Wood says. For a naturally aspirated motor, each cylinder should displace close to 500 cc. Fudge a bit to account for the slight extra displacement and you wind up with 12 cylinders, which is why the V-10, while popular with some recent supercars, just wouldn't do.
Early reports have called the Valkyrie V-12 a Formula 1 race car motor for the street, but that's a wild exaggeration. You know the soulful wail F1 cars are famous for? (Sorry, by "soulful wail" we meant the sound of an overly caffeinated swarm of bees on their way to sting someone to death.) That angry sound happens because F1 motors make nearly all their power at about 9,000 rpm. Drivers shift constantly to keep the engine spinning fast so ample power is always available. Fabulous for a race motor, useless on the street.
To be a decent street engine, the Valkyrie's had to make a solid chunk of its power much lower on the tachometer. Damn near no street car can even rev to 9,000 rpm, period. Freeway on-ramps aside, your engine spins between 2,000 and 4,000 rpm most of the time.
And then there's maintenance. Race car motors are, with few exceptions, built to last for the duration of a race. Even millionaires wouldn't buy a car that needs an engine rebuild every 500 miles. Which means the components that go into spinning the Valkyrie V-12 had to be exotic enough to withstand four-figure power at five-figure revs, but not so new and exotic that engineers couldn't be sure they'd last for decades. Cosworth stuck to known materials, and aside from some carbon-fiber structural components, it was made with relatively conventional steel and aluminum alloys.
Cosworth used one more trick to eke out more performance. Attached to the V-12 is a Kinetic Energy Recovery System, KERS in industry talk. The system recovers otherwise wasted energy as the brakes system slows the car, stores it for short-term usage, and provides short boosts directly to the engine (not the wheels, as with some more ordinary regenerative braking schemes) during acceleration. The KERS system isn't a Cosworth part, and so Wood can't say how much horsepower it'll add to the V-12's 1,000-hp figure. Aston also declined to release details.
One thing Aston is eager to discuss is how the V-12 becomes a crucial part of the Valkyrie's structure. A few previous street cars, such as the Ferrari F50, use their engines structurally, and even then it's always with a subframe for support. The Valkyrie is the first road car to use the engine as the only link to join the front and back of the car together without any kind of additional subframe.
“Obviously, the engine is there anyway,” Wood says. If you use the engine for two purposes, both power and structure, then you save a lot of weight. “It makes the job of the engine much harder,” he says, “because it has to not only contain the stresses of combustion, but it also has to transmit all the vehicle's stresses.” The scheme saved “many tens of kilograms,” he says. It doesn't sound like a lot, but for a car focused wholly on performance, it matters.
One last myth about the Valkyries. Another misconception that's been widely reported was that the motor would only last 100,000 kilometers (62,000 miles). For a road car, that would be an absurdly short lifespan. Wood says that number was simply a contractual requirement for a minimum number of miles that the engine had to last, not the projected lifespan, and the engine could survive far longer than that.
Cosworth performed dyno testing on a test engine to 100,000 kilometers, and when they stripped it down and looked at all the parts they found that the core components, such as the block and crankshaft, were still in fine condition. “Certainly, it's the case that from our experience in the first endurance test, it's very much that the engine could be rebuilt at that 100,000-kilometer interval and go again,” he says.
Most high-end supercars won't get anywhere near 62,000 miles of use in their lives, and it's a long shot that any Valkyrie owner will drive that far, But Wood wouldn't be all that surprised. “We were also involved with Aston Martin on the One-77 program,” he says, “and there was at least one customer who got up to nearly 40,000 miles in the first three or four years. It was his daily driver. Many (supercars) become investments, and others are used on holidays, but in our experience there are a handful of people who genuinely will use these vehicles as daily drivers.”
One hundred and fifty. That's it. Aston Martin promises to cap production of the supercar at a hundred and a half, which means only that many Valkyrie V-12s will ever exist—neither Aston nor Cosworth will use the engine again.
It was never meant to be a mass-production engine. But then again, the ambitious, blank-canvas projects—the places where engineers run amok—never end up being for the masses.