The Hill Was Alive… to the Sound of Gobstopper II

- August 17, 2015 - 5

Roger Clark Motorsport made headlines last month when it set the fastest overall time on the Goodwood Hill Climb in its Gobstopper II project, but the development that led to this achievement shows it was something of an inevitability.

RCM Gobstopper (25)

When rallying prodigy Olly Clark of Roger Clark Motorsport set the fastest ascent of the world-famous hill climb at this year’s Goodwood Festival of Speed, shockwaves must have been sent through the gentrified world of traditional motorsport.

RCM Gobstopper (1)

It makes us chuckle to think that monocles might have fallen from the wide-eyed befuddlement that a small, privately-owned tuning company had usurped the crown normally held by Formula 1 teams and works prototype cars. And what’s more, embarrassed this establishment in a machine that still retained the basic silhouette of a mid-size family hatchback.

RCM Gobstopper (20)

In all honesty, the Festival of Speed organisers could have predicted the arrival of this moment. In recent years, highly-tuned production cars have nibbled away at the time advantages held by supercars, hypercars and dedicated racecars. But few have devoured the Goodwood hill with such ravenous intent as Roger Clark Motorsport, whose latest four-wheel drive Subaru WRX STI – aka ‘Gobstopper II‘ – blasted its way to the top of the 1.16-mile course in just 44.91 seconds. (our GSII feature HERE)

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To put this achievement into perspective, only five other machines have put in a faster time since records began in 1999, and the majority of these racecars have subsequently been banned from making further runs for the sake of safety. Part of the reason for this is that unlike most other motorsport disciplines, there are no practice sessions; each run is timed. Your only hopes of memorising the course are to study the rudimentary map displayed at the start line, try to learn it in the virtual world of Gran Turismo 6, or get invited to Lord March’s house for dinner.

There is another form of motorsport that requires its competitors to compete against the clock on a single flying lap but not directly against each other – Time Attack. Gobstopper II was originally developed for Time Attack, and the more specific purpose of destroying every professional class record in the series. Yet when you begin to analyse the top-end products, technologies, talent and effort invested in this vehicle by brothers Matt and Olly Clark, there was an air of inevitability that this very special Subaru would raise the bar in other motorsport disciplines as well.

RCM Gobstopper (11)

Work on Gobstopper II began with a new bare-metal Subaru WRX bodyshell supplied by Prodrive. Though the third-generation Impreza monocoque is stiffer and safer than those of previous generations, a bespoke roll-cage was inserted that ring-fenced the car and became its new base structure. This inside-out reworking not only optimised the important suspension- and driver-mounting points for balance but allowed many of the external panels to be remanufactured in carbon fibre for lightness rather than strength. Meanwhile, the shape of these panels was partly dictated by having to cover the broad-shouldered, WRC-specification wheel track.

RCM Gobstopper (15)

Right from the outset, aerodynamic efficiency played a role in profiling the car. Computer fluid dynamics simulations helped dictate the shape and position of ducts and vents to generate through-flow for cooling. It even narrowed the location of the exhaust outlet to the aerodynamic ‘dead zone’ at the back of the car. Further simulations were also used to ensure the car scythed cleanly through the air and harnessed that passing atmosphere to literally suck it to the ground for physics-defying cornering speeds. Inspiration for the immense rear wing came from the aerodynamic addenda seen in the Global Time Attack series, the size of which is enough to make even a high-level STI spoiler cower in fear.

RCM Gobstopper (19)

Talking of striking fear, the original Gobstopper took many championship titles with a 720+bhp output that was considered monstrous at the time. Such is the rate of progression within the tuning scene, however, that nothing less than an output approaching four figures would have made much of an impression for its successor.

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Roger Clark Motorsport has spent years perfecting the race specification of its EJ20 closed-deck boxer turbo engines, and a comprehensive explanation of its workings would require a technical article of its own. But while much of the architecture and bespoke components have trickled down from the original Gobstopper (including the relatively tiny 2.0-litre displacement), the development process for this 900+bhp improved derivation required the finest brains in Formula 1 and aerospace fabrication to turn Matt’s inspired – but frequently leftfield – ideas into reality. And while this expertise has come at considerable cost for the company, the resulting products are now available for the general public to buy for their own projects. It’s a magnanimous gesture that you will struggle to find elsewhere within the aftermarket.

RCM Gobstopper (24)

A new loom consisting of aerospace-grade wiring and military-spec connectors shuttles electrical power around the vehicle, while the brains behind the engine and sequential transmission is a standalone management system that has to think so fast it needs five fans to cool it down. Control of a different kind is provided by the chassis, a truly bespoke setup that encompasses custom forged wheels, huge carbon fibre brakes designed for endurance GT racing, and custom forged suspension uprights that connect to the body via WRC specification cross members and wishbones. So complicated and precise was the CAD scanning for the uprights that each corner took a week of CNC machining time to complete!

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Olly’s race seat is sat much further back than Subaru originally intended, its position fine-tuned not for the comfort of the driver but for the best balance within the wheelbase. Only after this location was determined by corner weights were the steering wheel and pedals brought within reach. Similarly focussed is the flocked, carbon fibre dashboard, which has become nothing more than a shell for hanging the bare essentials. All unnecessary dials, buttons and vents have disappeared, replaced for the most part by a digital instrument cluster that consolidates vital information into one portal designed to be easy to read at warp speed.

Internet ready Gobstopper 2-14

Not that there is much time for Olly to look anywhere other than directly in front of him when he’s behind the wheel of this beast. Some doubt he even had the opportunity to breathe during that adrenaline-fuelled pass of the Goodwood hill. Most of us didn’t when watching the in-car footage!

And so we return to that wide-eyed wonder everybody felt when experiencing that ballistic ascent, whether in the flesh or at home on your computer. News of the achievement spread across the globe like wildfire, elevating Roger Clark Motorsport into the realms of motorsport royalty. With a great deal of time and effort, Gobstopper II has become a dedicated and world-renowned racecar but let’s not forget that this bodyshell could easily have become an economical family car. When put into that context, this has been quite a transformation.

RCM Gobstopper (4)

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