...but there is something deeply sinister lying under the hood - an 840bhp twin turbo engine for instance. Since our test drive it went on to break the record and become the fastest soft-top in the world at Nardo, too, cracking a simply insane 238mph.

World Record 238mph

Sometimes words just fall hopelessly short of explaining the force on offer from a car, and after the last of a series of 150mph runs in 9ff’s TCR-84, shaking hands and the need to sit down was all that company boss Jan Fatthauer needed to see.

It might look like a bog standard 997 Carrera 4S Cabriolet, but there is something deeply sinister lying under the hood – an 840bhp twin turbo engine for instance. Since our test drive it went on to break the record and become the fastest soft-top in the world at Nardo, too, cracking a simply insane 238mph.

Very few cars will match this one,” said Fatthauer, who is also responsible for another record breaker, the 400kph V400, so he’s not used to making idol boasts. “There’s the Bugatti Veyron, the Koenigsegg and maybe the Pagani Zonda F. That’s about it…”

He wasn’t lying, it took 3.7s to 60mph, at a very conservative effort, and the only thing stopping that time being cut by a further half second or even more was the fact that the tyres couldn’t keep up with the wheels. The stiff Continentals, the only tyres rated to the top speed, simply cannot put the power down and it’s even more complicated than simple wheelspin.

As well as all four wheels flailing for a grip like a drunk tramp fighting an imaginary stranger in the street, there is so much force heading through the tyre that the rubber slips on the wheel. Nothing will stop that and tall four wheels can even break traction at 130mph. Even in a straight line it is moderately intimidating and this is one of those cars that won’t just drive itself and takes a responsible approach to throttle modulation if you want to stay alive.

Despite losing a lot of that power on the way to the road, this beast will break through 200kph (125mph) in 9.6s and 300kph in 21.2s, which is monumentally fast and shows just how easy it is to run into trouble with the local law enforcement after just a few seconds of hard acceleration. It all feels even quicker, too, as with the soft-top down the noise is deafening, the freezing air rushing through the car acting as a constant reminder of the pure insanity of the task at hand and you can simply see more of the world melding into one constant blur. Considering the messy aerodynamics of a chop-top, the top speed is a pretty frightening prospect.

When 9ff conceived this car, he simply couldn’t get that kind of power from the 997 Turbo. He has now, with an engorged capacity and more trick measures, but with this machine he came up with a straightforward approach.

They threw the 997 engine away or, more precisely, into a Cayman, and planted a 996 twin turbo into this car. Of course that was the start of the operation, as they then bolted on some Garrett T35s – which even Jan admits might be a touch too much. They give more power than God, but they take time to spool up and whir and click for more than a minute after the engine shuts down.

Forged pistons, titanium connecting rods and Nikasil coating were all essential parts of the package, as was a beefy clutch and that elegant stainless steel exhaust with a braided finish on the small visible part. Inevitably the cooling system required some work, from a new intake manifold right and air feed pipes that look like they belong in an air conditioning unit through to an oil pump that could supply a ship. A 911 engine bay is never the most exciting place, but the technicolour fantasy world that lies under the hood of this machine is about as good as they’re ever going to get.

Of particular interest is the tiny yellow knob that you might not look twice at, until it’s pointed out. This is the key to even more power and the day before, having experienced boost pressure problems, the mechanics turned it up on a test drive. The resulting two-bar sent the horsepower figure rocketing well beyond 1000, which is suicide on four wheels. They swiftly turned it down again to a more sedate 1.4 bar.

When I turned up to drive this monster, I expected it to be an undrivable nightmare at any speed, at any revs, but that’s simply not the case. Treated with respect it is simply a little lumpy ad loud, but you could take it through town if you have a steady right foot. Beyond the 4000rpm watershed, though, this machine turns into the automotive equivalent of a serial killer who feasts on brains. It’s so mad it should be in prison, forever, in solitary confinement.

Which makes it all the more remarkable that the chassis is basically untouched. Porsche’s PASM system is so good that Jan decided the car just didn’t need the fully adjustable Bilstein set-up that he offers as a cost option. And the brakes, too, are fine, although Jan has upgraded the front discs to 380mmx34mm with new four-piston callipers inside the lightweight 10-spoke wheels.

It is a high compliment indeed that an engineer of Jan’s calibre believes a chassis designed for just 355bhp can handle more than double that. And it’s perhaps even more impressive that the new owner of this car intends to take it drag racing. They will laugh at the girly Porsche when it arrives at the strip and they will go home broken, beaten and possibly crying.

The driver of this machine, meanwhile, will go home crying tears of pure joy. Once his hands stop shaking, of course…

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