Exactly how fast is the Ford Mustang R-Spec?

Have you ever tried to do something which, on the face of it, is a relatively simple assignment but rapidly descends into an exercise in pure frustration? I’m talking assembling an IKEA chest of drawers with some of the fasteners missing, or editing the paired phone list in a Lexus; those levels of wall-punching exasperation. Add ‘trying to extract a meaningful acceleration time out of a Ford Mustang R-Spec’ to that list.

Don’t get us wrong. We’re fans of the 500kW R-Spec. It’s just one of those cars that demands you be at the top of your game to get the optimum performance from, due to the combination of manual gearbox, prodigious power output, and relatively narrow rear tyres.

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I had first crack at delivering some acceleration times that were potentially cover-worthy for Wheels magazine. You guessed it: it turns out they weren’t. I wasn’t that impressed by the 4.7-second time to 100km/h I achieved after a number of aborted attempts to get the ’Stang to hook up. Getting that sweet chirp of wheelspin and then a clean feed of power to the rear Michelins seemed only marginally easier than getting Warwick Capper to explain Fermat’s Last Theorem.

Too little grunt and it would bog, too much and it would immolate the rear treads. Part of the problem is that the 275/40ZR19 Michelin Pilot Sports 4S tyres on the back are narrower than the rubber you get on the front of a Camaro ZL1. Still, that’s the tyre that Ford Performance recommends. To get the best time from them, you’d need to deflate them to around 18psi, which isn’t representative of a real-world use-case so we stick with the placarded pressures.

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Conditions are otherwise favourable. It’s cool (18 degrees) and a bit blustery at Heathcote and, when we do pull a full-blooded run down the strip, the R-Spec seems to be delivering at the top end. The numbers spat out by the Racelogic Performance Box give us that 4.7 seconds to 100km/h and a 12.4 seconds through the 400m mark at a speed of 199.1km/h. I feel a bit dejected. Those aren’t times significantly removed from those of a stock Mustang GT auto.

Admitting defeat, we hand the car back to Ford and it then goes straight to the guys at MOTOR. Hats off to the perseverance of Scott Newman for extracting an identical 4.7 second 0-100km/h time on a day that was fully 11 degrees hotter. But where Newman may have been helped by a stickier launch pad, conditions then conspired against him. Scotty complained that the car felt strangely flat at the top end, delivering a 12.8sec 400m time at 189.6km/h. That’s 9.5km/h down at the far end of the strip.

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We spoke to Rob Herrod about our times and he agreed that the car was tricky to launch cleanly. He also noted that the ECU was critical and would protect the engine if it detected overheating or poor fuelling. He also predicted – to the tenth of a second – the time we had achieved and claimed that the optimum time this car could achieve, with burnouts and partial tyre deflation, was a 12.2sec.

So, it seems the R-Spec likes a cool morning, soft tyres and a bit of finesse in a partial lift and then feed of clutch. Or, to put it another way, think twice about giving the guy in the Supra a bit of aggro at the stoplight. Of course, the R-Spec has a whole host of other awesome qualities, but getting it off the line cleanly? Pass me the instructions to that MALM chest of drawers again…

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THE NUMBERS