Apparently this is the best place to hear it from. Standing round the back of Cell 9, a dyno room in the bowels of Cosworth, one of the engineers waggles a long door handle that looks like it might open an industrial freezer. He’s letting those controlling the engine on the other side know that we’re ready. The cells are meant to be soundproof, but they can’t quite contain the screams of engines from World Superbikes or Formula 1 cars. Or, as we’re about to find out, the Aston Martin Valkyrie.
“The sound is angrier and wilder than that of any road car engine I have ever heard”
For some reason I close my eyes as the revs flash through their first buzz-saw crescendo, picturing a Valkyrie leaving the start line at Silverstone, the circuit they are simulating. The sound is angrier and wilder than that of any road car engine I have ever heard. In this feral state it’s hard to call it musical, but as it accelerates along its virtual Wellington Straight I know it is doing something very, very right. Why? Because the hairs on the back of my neck are all standing up. Then Red Bull (not Aston Martin) first approached Cosworth in 2015 about the nascent project, the numbers requested were a 6-litre V12, producing 950bhp and weighing less than 200kg. What we have here, three years later, is a totally new 6.5-litre V12, producing 1000bhp, 740Nm of torque and weighing 206kg without exhausts. Bruce Wood, managing director of Cosworth, is keen to stress that those 1000bhp are all very much present and correct. They’re not achieved ‘with the dyno pointing downhill’ as he puts it.
But what is really exciting is that this naturally aspirated engine’s 1000bhp is achieved at a sky-high 10,500rpm. The V12 will actually go on to 11,100rpm. That means piston speeds up there with F1 engines and a limiter over 2000rpm higher than that of a Ferrari 812 Superfast, which has probably the most exciting engine on sale today. Perhaps unexpectedly, the Valkyrie’s engine began its physical life as a three-cylinder. About seven months before Cosworth built the first V12, and about five months after the first blank sheet of paper, a quarter of this engine, complete with exhaust and catalytic converter, was put onto a dyno to test the combustion simulations. I rather like the idea of a 250bhp three-cylinder propelling a small supercar…
“This V12 will be a structural part of the Valkyrie, whereby if you remove it, the front and back of the car will no longer be connected”
The final, 65-degree V12 we have here is made from an extremely expensive aerospace aluminium alloy with plenty of titanium internals (apart from the carbonfibre components, everything is made by Cosworth itself). The company could have used more exotic materials, but then it wouldn’t have been certain how the engine would fair in 40 or 50 years’ time, and all concerned want this car to be an icon that will last. Talking of which, the intended life of the engine is 100,000km, with an oil change every 5000-6000km. The engine that we heard on the dyno is the second one to go through a 220-hour durability test, while other engines are also being tested for performance and calibration on two further dynos down the corridor.
Because, amazingly, the engine is designed for a road car and not just a track toy, there have had to be compromises. For a start, the gear drives for the cams have been moved to the back of the engine. This isn’t as good for the overall length of the engine, but the NVH from having them hard up against the carbon tub would have been unbearable. And while a small and light carbon clutch would have been much easier from an engineering perspective, its light-switch behaviour wouldn’t have made driving down the King’s Road a pleasant experience, so a heavier but more forgiving sintered clutch is being used.
“What we have here, three years later, is a totally new 6.5-litre V12, producing 1000bhp, 740Nm of torque and weighing 206kg without exhausts”
According to Wood, the most challenging thing about producing this engine, however, was nothing to do with achieving power, durability or drivability goals. The most complex bit was designing the cam covers that also act as engine mounts. You see, this V12 will be a structural part of the Valkyrie, whereby if you remove it, the front and back of the car will no longer be connected. Cosworth has rather a lot of experience with this sort of thing, given that it produced the first ever stressed-member engine in the form of the iconic DFV. However, the Valkyrie posed a few new problems. Its engine is rigidly attached to the car’s carbon tub by just four bolts (not unusual), but because this is a two-seater, not a single-seater, it means the attachment points at the top have to be much higher and farther apart, and commensurately stronger (while still keeping that 200kg target in mind) in order to take all the huge cornering and aerodynamic loads. ‘I think in our plans we allowed about six weeks for the cam cover analysis,’ recalls Wood, ‘but in the end it took something like two man years!’
Other hurdles were encountered with the extraordinarily tight packaging of the engine in the car. ‘Every sugar cube of volume is filled with something,’ says Wood. So, there is some light machining on the back of the cam covers to allow the angled radiators to fit, while the torsion bar for the rear suspension actually passes along the top of the engine beneath the plenum. The bottom of the engine’s V has also had to be left clear to allow room for the huge Venturi tunnels. And at almost every stage, Adrian Newey, the Valkyrie’s mastermind, has apparently challenged Cosworth’s decisions (such as moving the gear drives), pushing it to produce the very best. A good example is the beautiful carbon plenum. The first thing Newey wanted to know when he saw it was how much weight the lacquer added. You can now have your Valkyrie 80g lighter by specifying the plenum without the high-gloss finish…
Over the coming months we will no doubt learn more and more about the Valkyrie and the lengths to which Newey has pushed people to achieve his vision for the ultimate road car. But for now, what we can say is that however extraordinary, bamboozling and possibly unrelatable the cold, hard facts and figures of the Valkyrie turn out to be, underneath it all there is going to be a very emotive V12 heart.