Stop The Clocks: Gobstopper II Unleashed

- October 3, 2013 - 4

Photography: Bryn Musselwhite

After one of the most comprehensive builds in motorsport history, the Clark brothers are finally back with their latest masterpiece in metal. Gobstopper II must be one of the most hotly anticipated tin-tops to ever roll out of a workshop and it’s been built with one harshly-focused raison d’être in mind… to destroy every single lap record in Time Attack.

RCM Impreza (35)

For any musician, having a runaway hit debut album is something of a mixed blessing. Sure, it’s wonderful to enjoy the success and adulation that a string of hits can bring you, but once the last single has been released and the final party is over; the industry and fans turn around expectantly and wait for you to do it all again.. only better.

RCM Impreza

It must be a similar feeling for brothers Matt and Olly Clark and the small, but perfectly formed team at Roger Clark Motorsport in Hinckley Leicestershire. Simply down to a cocktail of insane hard work, engineering brilliance and more than a little talent behind the wheel, the shapely GC8 Impreza that was Gobstopper I began a meteoric rise through the ranks of its motorsport peers to win the hearts and minds of fans everywhere, as well as a serious haul of silverware. Very few modern day race cars get to be called ‘iconic’, but the original Gobstopper, with its distinctive white livery and red and black stripes, allied to concours-level presentation, can certainly claim that honour. When model car maker Corgi calls you up and asks if they can add your race car to their ranks of collectibles, it’s fair to say that you’ve entered the public consciousness somewhat…

RCM Impreza

So, faced with a smash hit straight out of the box, two UK Pro Time Attack titles and three ‘Ten Of The Best’ and ‘Tuner of the Year’ titles, would could the talented duo do next? Should Gobstopper I be updated? Mutated into an evolution of its former self? Or replaced altogether with a clean sheet of paper and a whole raft of new technology?

RCM Impreza

‘This was an easy decision for us to make,’ explains Matt. ‘Gobstopper I is just too precious to us as it is. We owe everything to that car, as it’s the only way we really advertise what we do as a company. It brought us so much; so many new friends and customers and a great deal of business around the world. To change it would have been sacrilege, really! We knew it had to be an all-new build. It’s a lot to ask from any fresh project, but we felt that if we could achieve even a fraction of the success we had with the old car, we would be elated.’

RCM Impreza

So the hunt was one for a new Subaru platform. With the old car clearly setting the bar very high, Matt had to do some deep and leftfield thinking to create the bare bones of his next masterpiece. ‘I didn’t want us to get known as a ‘one trick pony’, he continues. ‘I wanted to do something really new and exciting, and create an engineering showcase that was bang up to date with the latest technology and thinking. Many things have moved forwards since we built GSI, and I wanted to reflect that new ideology’

RCM Impreza

GSI had evolved from a competition-shelled GC8, but its successor would be a different animal. ‘In most race cars, the cage adds integrity to a shell that’s already there’, says Matt. ‘For this next build, I envisaged it almost the other way round, with an extensive cage providing the real strength and integrity, with the bodywork almost draped on top.’

RCM Impreza

The ’08-on WRX body shell was chosen as the basis, and thanks to having a certain Mr. Dave Richards as an old family friend, the brothers managed to get hold of the last bare-metal WRX shell at Prodrive, which would save a simply enormous amount of stripping down, and allow them to start with the basics.

RCM Impreza

To get the car right from the outset, Matt whisked the virgin shell down to Andy and Simon at Custom Fabrication. Here, true to his vision, the car was carefully dissected into its component parts as a plethora of T45 tubes were added. Simon and Andy used to be part of the SWRT WRC talent pool, so the cage was created around that design as a first reference, but with a great many additional elements added to allow the safe removal and lightening of almost every metal panel on the car. Suspension pick-up points were added in to Matt’s design, as were air-jack tubes, front wheel tubs and a multitude of strengthening gussets. As the pics show, the work here was considerable and took many weeks of ceaseless toil. The bill for this simply sublime level of work? ‘Er… more than you might think,’ say Matt bashfully. ‘But then I promised our Mum I would make it really safe for my little brother!’ he says with a knowing smile.

RCM Impreza

With a careful dust of primer to protect the virgin surfaces, the shell was trailered back to RCM’s Hinckley HQ to allow the ‘dry build’ to commence around a dummy engine and box. Panel work was the first job on the list, so the team began with a set of WRC panels and worked from there, adding vents, cutting holes, and using body filler to get the correct profile and flow. There were no grand ideas for sophisticated aero at this point, so most of the shaping was done using a combination of experience and good old common sense. Track was set at the lowest and widest width for a WRC car, to get a reference base point, and then the finished ‘buck’ panels were sent down the road to F1 carbon fibre fabricators, KS composites, to create moulds, which would later be used to recreate the panels from the lightweight  black stuff. The list was quite extensive, with the wings, roof, doors, bonnet and bumpers all being made in the wonder weave. The tailgate would be a rather trick STi alloy item, but the act of fitting the rear spoiler really got Matt thinking. ‘It was about this time, I really started to think about future-proofing the car,’ he explains. ‘Our early renderings were fairly tame on the aero front, but as I did more research and began to get more excited about what was happening in the Global Time Attack arena, I realised that we might need to go a little bigger here too! Who knows? We might be lucky enough to get invited overseas at some point to have a little tussle with some of our friends in other championships.. and you can’t turn up with a knife to a gun-fight, can you?’ At this point, Matt vowed to return to the aero issue and cracked on resolutely with the rest of the build.

RCM Impreza

Although GSII would have an all-new engine, this was the one part of the project where Matt had much of it already laid out in his head. GSI had proven to be a remarkably reliable and effective device, so the thinking behind the new motor would be a gentle evolution of that power plant. What would need to be made from scratch however, would be an all new wiring loom. This was made over a painstaking 5 week, non-stop period by using lightweight ‘Spec 44’ aerospace grade wire and military spec connectors. Connections were made to hook up the MoTeC dash and Syvecs engine management system, as well as the sophisticated Zytek paddle shift. As with GSI, a MoTeC PDM replaces the chores of all fuses and relays in one neat little box.‘The Syvecs unit is just so much quicker and smarter than the MoTeC ECU we ran before,’ says Matt. ‘It also integrates seamlessly and efficiently with the new CAN-BUS systems on the car, so it’s far more suitable for what we needed.’ Ex-Time Attack ace and friend of the team, Paul Blamire, was drafted in to set the entire system up, with Matt simply raving about his ability to make it all work like ‘factory’. ‘Paul is simply a genius when it comes to this kind of stuff,’ he says seriously. ‘He really made this part of the build possible. We couldn’t have done it without him!’

RCM Impreza

Suspension duties came next, and as with everything else on the car, Matt wasn’t about to bolt a set of ‘off the shelf’ solutions onto his pride and joy. The cross members and wishbones may be based on WRC tarmac spec S14 units, but the uprights are beautifully made to RCM’s own design. Using the latest CAD and scanning techniques, key pick up points were logged, along with the wheel dimensions, brake mount points and the functional requirements of the gorgeous Ohlins TTX46 coilover units. These of course, were also custom filled and valved, before being equipped with a carefully selected range of Eibach ERS springs. The resulting upright was CNC machined from a 40 kg solid billet to take a Subaru wheel bearing, taking an entire week of machining time per corner!It sounds easy when you say it all like that, but you can imagine the work and head-scratching that went into it all!

RCM Impreza

Inside the car, Matt used a carbon moulding of the OEM dash to save weight, which was flocked to reduce glare. But why right hand drive? Surely all competition cars are left hookers aren’t they? ‘Well that’s one way of looking at it,’ says Matt, ‘but Olly and I much prefer the feel of a RHD car. We can both drive LHD, for sure, but if you have the choice of doing things exactly the way you want, then that extra familiarity could give us a few vital tenths. Besides, the LHD argument is only ever really relevant if you’re trying to sell it later… and that’s not going to happen!’

RCM Impreza

With jobs progressing around the build of a smart new premises, which Matt was doing much of the work for while Olly continued to run the show, progress on GSII was steady, rather than rapid at some points in its build. The next job would be the fuel system, based around a custom-made 38 litre Premier fuel tank that sits low in the floor. Using twin Bosch motorsport pumps firing race fuel through Goodridge Nomex lines, it will be just enough to give Olly around 20 minutes of flat-out running.

RCM Impreza (9)

The lubrication system was developed almost entirely in-house and centres around RCM’s own dry sump system. Despite Matt’s initial thinking of carrying over some of the technology here from the old car, ultimately, this was all started from scratch and created anew.

WRX Impreza

The spec of the engine would fill an article on its own, so it’s perhaps best to skip to the tech spec if you want the full low down here. Suffice to say, it’s a balance of the proven technology that powered GSI, but with a healthy number of new parts and tricks to turn the wick up a little more. RCM is most unusual in the motorsport fraternity in the fact that it’s always confident enough to tell people exactly what is in their engine, offer it all for sale, and then even offer advice on how to put it all together. Many competitors have enjoyed this openness over the years, buying all of their parts from the brothers in an attempt to build a Gobstopper of their own. ‘We’ll help anybody to build a car like this,’ says Olly. ‘Every single part of this car, pretty much, is available to buy from us. What’s the point in developing these amazing solutions if you don’t put them out onto the market? It’s Matt’s magic that adds the little extra sprinkle of fairy dust, so hopefully, that should keep us near the front!’ Ultimately, Matt built two identical engines; one to build into the new car, with another twin unit which ran in the old car at Croft to prove the technology. With a convincing overall Pro-class victory under its belt, Matt felt confident to finish the second engine the exact same way!

RCM Impreza (15)

At this point, the boys were starting to have second thoughts about the aero package once again, so Matt decided to commission the scanning and full flow analysis of the car in order to create a truly functional design. This involved the car being completely laser scanned, and then rendered in 3D, before numerous computer fluid dynamics (CFD) simulations were run to ascertain the perfect size, shape and position of all spoilers and side plates. These were them created by KS composites and then extensively wind-tunnel tested to ensure that they worked as well as they look. ‘I’m looking forward to driving a car with a truly functional aero set-up!’ exclaims Olly. ‘Having seen the work that’s gone into it all, I know it works well, so we should have much greater cornering speeds than with the old car.’

RCM Impreza

Another aesthetic highlight is the fully custom wheels. Again, these were made to Matt’s precise specs by the boy’s good friend, Matt Neal. Well, not him personally, obviously, but the BTCC star’s Rimstock company took time out of machining wheels for well-known British supercar makers and used their five-axis mill CNC machinery to create a set of these incredible rims from a solid forged billet. Just another example of how only the best would be good enough for this build. These are shod in Olly’s preferred choice of Pirelli rubber at all rounds; slicks for the dry and bespoke wets for when the rain falls. Behind the wheels are AP carbon brakes, with the option of steel alternatives to suit track conditions. ‘AP Carbon is certainly the way to go, but it does have a finer window of optimum performance’, say Olly. ‘It’s nice to have the choice between the two mediums, so we can run steel on colder days or tighter tracks.’ AP Racing has also supplied the trickpedal box and quad-plate clutch and the manufacturer clearly has found favour with RCM’s technical guru. ‘I won’t fit anything else,’ says Matt. ‘We’ve tried everything, and AP stuff simply just works. We never get any hassle with it and it helps us to win. It’s all you can ask from a component, isn’t it really?’

RCM Impreza

With everything almost done and dusted, the RCM gear kit built into the trans, the shell exquisitely painted by SGM Race paint and the heated screen ready to go in, Matt could begin the long and careful task of putting it all back together, ready for its initial launch at the Autosport show. And that’s the thing to remember here; due to its innate professionalism, and the mind-blowing levels of preparation that RCM has, people often wrongly assume that they have got to where they have by sheer man-power behind their race effort. But, in truth, it’s probably the smallest team out there. The car is prepped solely by Matt, with only the odd job like wiring and painting getting farmed out for a little extra help. On race day, it’s just Matt and technician Mark supporting Olly, yet this little team of three still manages to get the job done. Sure, the car may have cost more than most…more than a rather nice house, in fact. But, when the dust has settled, remember, this is the sole advertising the company ever does, and this spend will last for many years. Besides, which customer doesn’t like to think that any money being made from the sale of their goods is going straight into the build of the world’s most amazing Subaru? It sounds like the perfect outcome to me.

RCM Impreza (1)

Chatting to Olly again, I had to ask the question of whether the weight of GSI’s success would weigh heavy on the shoulders off its offspring? ‘I don’t see it like that,’ he smiles. ‘They’re two completely different entities, and the work we did with the old car gives this one a great starting point, I think. Don’t get me wrong, neither Matt or I expect anything other than a learning curve with this car during its first few outings. Very few race cars hit FTD straight off the trailer, and even with a brother as talented as mine, I’m not expecting my first few laps, or even meetings, to be any different. There will be gremlins, for sure. I know it’s a great car under me though, and that gives you incredible confidence as a driver. We’ll get there though;and hopefully sooner, rather than later.’

AP Racing breaks

At this point Matt chips in, ‘And we’re lucky in Olly’s skills too. We’re often asked why we don’t field a professional circuit driver, rather than Olly… as like Dad, and me, he’s a rally driver at heart – not a racer. But he’s the only bloke I trust with this car, and he’ll build an affinity with it that we’ll never get from a ‘hired gun’. Sure, there are possibly technically quicker drivers out there, but no-one matches him for bravery and spirit… and that’s what has taken us to titles in the past.’

RCM impreza

It’s then when you realise what that magic ingredient on this car truly is. The bond between these two brothers and the trust that this creates, allied to an incredible level of complimentary talent on both sides means that each one instinctively knows that the other will get the job done, no matter what. It’s also patently clear that the two have an awful lot of fun doing it, too.

Gobstopper II

Although it still hasn’t fully run in anger, as awkward second albums go, GSII seems to be packed with a string of catchy hits. It’s what the fans wanted, it’s what the industry wanted, and although it’s not perhaps what the rest of the Time Attack field ideally wanted to see rolling off the trailer, even RCM’s most ardent competitors admit that this car is a thing of beauty. Built to a quality first and foremost, and a budget and timeline second, it’s a stunning example of British craftsmanship and ingenuity. The last word however, has to go to Olly. ‘All I really hope for this car,’ he says, ‘Is that it has the same effect on enthusiasts as the first one did. Not only did we meet so many amazing people through that car, friends that became customers – and customers that became friends, but we know that it also inspired people to start their own Subaru builds or prep their own Time Attack cars. A really nice guy came up to me at a Time Attack round once and told me that seeing the Gobstopper had inspired him to build his own car for the series. To me, that was worth just as much as the titles. It’s great to know that these cars make a difference to people.’

RCM Impreza


Pirelli, Samco, Arrow Precision, Ohlins,Goodridge, Turbosmart, Custom Fabrication, Sabelt, Recaro, Lifeline, Omega, Asnu Fuel Injectors, Paul Blamire, SGM Racepaint, Tony at TDV Autosport, Richard Woodgate at Zytec, Bill Condon, Ian Nash and Pete Collen at AP Racing, Charlie from Syvecs, Richard at Laranca Engineering, Matt at Rimstock


-2.0 (!!)Subaru EJ20 Engine
-Garett hybrid 4094 turbo
-Turbosmart 50mm external wastegate
-2.0 closed deck block
-RCM gas ring conversion
-RCM arrow M2000 con rods
-RCM 75mm Arrow steel crankshaft
-RCM lightweight Omega pistons
-RCM big valve‘O’ ring type heads
-RCM engine valves
-Titanium retainers
-RCM ‘R profile’ tight wrap cambelt system
-WRC SI0 inlet manifold
-RCM 8 injector kit
-I000cc injector x 8
-RCM FBW throttle body
-RCM 7.5 litre dry sump system
-RCM Inconel short runner exhaust manifold
-K&N air filter
-RCM Intercooler water and oil cooler system
-Uprated single valve springs
-4” exhaust with thermal coating
-Zircotec coated manifold.


-AST carbon prop
-RCM custom driveshafts
-RI80 STI rear axle
-3.9:I crown wheel and pinion
-With custom RCM diff cover
-6 speed gearkit with RCM sequential mechanism incorporating Zytek paddleshift
-Clutchis  AP Quad Plate Carbon
-RCM low inertia 2.5kg flywheel


-Brakes AP Steel 365mm front 340mm rear
-Carbon 380mm front.340mm rear
-AP hydraulic handbrake
-Ohlins TTX Dampers with Eibach Springs
-Custom RCM Billet Uprights
-WRC arms with custom chassis mounts
-RCM top mounts
-Team Dynamics fully forged five axis milled 18×10”Alloys
-Pirelli tyres slicks and wets.


-Custom RCM Carbon Fibre Body panels
-Alloy STI rear hatch, Lightweight windows and heated screen
-Honeycomb flat floor
-Custom aero package, Krontec Air Jacks


-Recaro HANS seats / Sabelt harnesses
-Lifeline safety system
-AP Hydraulic handbrake,Autotelintercom
-Carbon Reverie steering wheel, Bespoke carbon Fibre panelling
-Custom Fabrications T45 cage
-Lightweight panel work

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  • aclasschris September 21, 2013 - 11:46 pm Reply

    Great write up! I still prefer their original GC8, however there’s no denying the Gobstopper II is a stunning achievement.

  • Matt Rus September 22, 2013 - 1:10 am Reply

    There will be also GS I feature. Stay tuned.

  • Please... September 22, 2013 - 11:29 am Reply

    Can we please have some high res versions?

  • Banzai feature on Gobstopper two.. October 4, 2013 - 10:26 pm Reply

    […] we go Stop The Clocks: Gobstopper II Unleashed | Farmofminds QUOTE by Scubbay – Hit the backroads 12 at night window down and nurspec singing. Job […]

  • RCM Gobstopper II | A Class™ April 30, 2014 - 4:51 pm Reply

    […] 2014 UK Time Attack season. If you’d like to learn more about the car, Farm of Minds did a great feature back in […]

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  • […] 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 […]

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