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Aston Martin Valkyrie: What goes into a 1000bhp Cosworth engine?

The internal-combustion engine might be entering its third age and getting sized up for a place in Sunshine Acres, but it's not going out with a whimper.

Indeed, in the spectacular form of the 6.5-litre V12 set to power the forthcoming Aston Martin Valkyrie we might have the ultimate expression of a road-legal, suck-squeeze-bang-blow powerplant.

We've already told you a bit about the Valkyrie, the beyond-hypercar being jointly developed by Aston Martin and Red Bull Racing under the leadership of Adrian Newey, the most successful F1 designer of all time.

Although it'll be a hybrid, the electrical part of its powertrain will be a minority partner, and a pretty much silent one at that. A chance to visit Cosworth in the UK and see the V12 being put through its paces on the dyno gave a hint at how special its internal-combustion engine will be.

There are few more evocative names in engineering than Cosworth. Although the part of the company responsible for famous road-car projects like Ford RS Cosworths was hived off some time ago, the remainder remains a serious force in engine design – and therefore an obvious partner to develop and build the internal combustion side of the Valkyrie's powerplant.

The Newey-derived targets were simple, if incredibly demanding: the motor needed to be a naturally-aspirated V12 (a turbocharged V6 was considered and discounted). It would need to be strong enough to act as a structural component in the car, as in a racer, and it would need to make 747kW, corresponding to a 1000bhp peak output.

Then there was the small matter of an ultra-demanding durability requirement.

Cosworth was prepared to commit to those targets, with managing director Bruce Wood saying it took 13 months to go from a clean sheet of paper to running the engine.

It's now well into a testing cycle, my visit taking place as the second durability prototype was put through a 220-hour test cycle strapped to the bench in one of the company's dyno test cells. This enables different loads to be simulated at the flywheel, with today's challenge being repeated virtual laps of the Silverstone track, the engine receiving the same workout as if it was propelling a real Valkyrie around the circuit.

Even through the substantial double glazing separating the dyno from the control room, the engine can clearly be heard working, displays showing it's revving well beyond 10,000rpm - the red line is 11,100rpm and the spark-cut only calls time at 11,400rpm.

A power readout removes any suspense as to whether the motor can meet its claimed peak: it's showing 1000bhp within a few seconds of the cycle starting. (Peak torque is also confirmed: 740Nm at an altitudinous 7000rpm.) A chance to go and listen next to where piping carries exhaust from the cell proves it sounds properly amazing unleashed, the crescendo still growing well beyond the point where instinct tells you to expect an upshift.

Bruce Wood is straight from the Gordon Murray school of engineering: floral shirts and almost boyish enthusiasm for his subject. He joined Cosworth 32 years ago, having survived what he still remembers as a ferocious interview with company founders Mike Costin and Keith Duckworth.

Despite having worked on dozens of road and race engines over the decades, he clearly regards the Valkyrie's donk as being pretty special.

"This is definitely a pinnacle engine. A car like the Valkyrie needs an engine that is as special as it is – it's not just about delivering straight performance," he says.

"Making an engine that can produce these numbers is well within the realm of what's been done before, but making one that can hit emissions and durability standards was always going to be far tougher."

The original idea was for a 6.0-litre displacement, but that was only be good for around 700kW, hence the increased capacity. The engine doesn't feature any radical tech, but very high grade alloys, with billet-milled titanium valves and connecting rods. Block and cylinder heads are cast from aircraft-standard alloys.

The camshafts are cog driven, Wood says chains wouldn't have been able to cope with the required redline. One mild surprise is the use of indirect port injection instead of more modern direct injection. Blame emissions – direct-injections engines need particulate filters to meet forthcoming European standards, which would have added too much weight and complexity.

Newey's durability target was particularly tough: the same 100,000km engine life Mercedes-Benz is chasing with its Project One. (Development of that car is happening barely 30km from Cosworth's HQ, such is the scale of the UK's 'Motorsport Valley'.)

Wood refuses to trash the competition, but there's no question where his loyalty lies.

"I think that the Valkyrie is a very personal expression of Adrian Newey's vision of a car, whereas I'd say the Project One – which I'm sure will be a magnificent vehicle – is less an individual's view and more of a corporate one," he says.

While acknowledging very few owners are likely to drive their Valkyries to anywhere close to 100,000km, Wood insists it's a realistic target.

"Our expectation is that at 100,000km [the engine] would be replaced," he explains.

"That's not to say we think there is going to be a hole through the side of it, but our expectation would be that a lot of the components would be worn out.

"The reality is that if anybody got to that point we'd take the engine out, strip it and crack test it. If the block was fine and not excessively worn there would be no reason not to rebuild it with new pistons and valves."

The cog-driven camshafts also created a heated debate with weight-obsessed Newey. The noise they generate at higher revs, together with the engine's rigid mounting to the car's tub, would've created what Wood reckons would be an unacceptable level of noise and vibration had they been located, as usual, at the front of the engine.

Moving them to the rear has added a small amount of weight, but means there's now 750mm of engine separating them from the cockpit.

"It was quite an argument with Adrian," Wood remembers, "he said it would be lighter and shorter to put them at the front, which it would be, but then nobody would be able to spend more than five minutes in the car."

Despite that, Cosworth has managed to get the dressed engine very close to the programme's weight target of 200kg; Wood says it is 206kg including ancillaries and exhaust manifolds.

Newey's mania to shave mass is exemplified by the fact lacquer for the carbon-fibre air box will be optional: doing without saves 80g.

Aston is determined to drip-feed technical details over the next few months, but we did learn a bit more about the hybrid system. The Valkyrie will have an electric motor between the V12 and the gearbox, with outputs blending before reaching the rear wheels.

It'll be capable of operating under pure electric power under gentle use, although we're told that the engine will always be turning when the car is moving. Another intriguing detail is that reverse will be electric-only.

A huge number of questions remain unanswered, but there's also a huge amount to be excited about already.

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