Top Dog 722 bhp - Subaru GC8 Impreza

[JoeThaMan]

Top Dog 722 bhp - Subaru GC8 Impreza
Many people in the business reckon this Subaru is the best the UK has to offer-and with good reason. The facts and figures speak for themselves. This car won the '07 TOTB-the UK's prestigious handling, top speed and dragstrip competition- the Scooby Shootout Handling competition and finished second overall at the '07 Time Attack. It produces 605 bhp at the wheels or 722 when the gas is switched on; so figure on about 800 at the flywheel. To build, the car cost 150,000 and has reached 194 mph and a recorded 9.59-second quarter-mile. Despite that multitasking competitive pedigree, it's still road legal and immaculate enough to be entered in concours.
"The whole concept for the car was that it had to be a show car, a race car and a drag car," says Roger Clark Motorsport's Matt Clark, who built the car. "We wanted to build an all-round car, which could do anything." That's a great description of the Subaru and the results confirm it. Bear in mind, however, that the car runs in basically the same spec regardless of what the event is, so some kind of compromise is inevitable.
The car is the result of four months of Matt's hard work and is an "Evo" version of an earlier customer's car that produced 800 bhp and was the first Subaru in the world to clock a 9.8-second quarter-mile with a manual gearbox.
"We wanted to stick with an old Subaru shape because it's still the car that everybody loves, especially with those wide arches," he says. "Those arches are a '99 WRC kit and so are the bumpers and boot spoiler. We had to add strengthening struts to the wing regarding midrange power. And because it was bigger than the GT35 it replaced, it didn't need to work as hard." He says the twin scroll helped to cancel out any extra lag.
A lot of this car was fabricated to meet Matt's specifications, and he's especially proud of the six-speed sequential gearbox that he had designed and built. You can now buy one from RCMS with the same spec for 18,000.
"It's reliable, fast and very strong," Matt says. "The big turbo cars are frantic once they get going and the engines are high strung. With a dog box, you can change into any gear at any speed and it blows your engine in the process. It's happened to a couple of people I know this season, but you can't do that with our box." The car is also fitted with an optional paddle shift system for when the driver-Olly, Matt's brother-is too busy to take his hands off the steering wheel. Although, he hasn't really had enough practice to feel comfortable using it.
So what does Olly make of the car his brother built? "It's been built in the ruthless pursuit of perfection," he replies. "If it's not absolutely perfect then Matt won't compromise and the whole car reflects that." Despite a successful rally career, following in the footsteps of his late father, Roger Clark, Olly has limited experience on the track but, as results show, he has adapted quickly and been a consistent front-runner.
So what's the car like to drive? "It's impossible to describe how fast that car is," Olly says. "It did 194 mph at TOTB from a standing start and since then we have added some more ignition at the top end, so it should be good for 200 mph now." He also says that the car is still docile enough to take your granny to the shops. Although, that would be a waste of its impressive potential. "It's absolutely brutal when the power kicks in between 4,500 and 5,000 rpm," he says. "And then it keeps pulling all the way round to 8,500." He describes the suspension as "awesome with some understeer," but admits that is an area that they plan to develop further.
Early teething problems with the nitrous bursting alloy boost pipes was resolved by switching to a direct-port system with individual jets for each cylinder, which has been successfully used on the dragstrip and the long straights at Silverstone.
For the 2008 season, Matt is hoping to trim a further 60kg from the weight and increase the power to around 750 at the wheels. Those two improvements alone, combined with Olly's increased experience on the car and the circuits should ensure that it will be the front-runner that the rest of the pack will struggle to keep in their sights.
'07 TIME ATTACK (Overall Runner-up)
Round 1: Donnington Park (Second overall) With no real testing before the event, the car still put in a solid performance straight out of the box. "It was pretty surprising that we were so much on the pace," Olly says. "We hadn't put much time into the suspension setup and it was a bit of trial and error to establish a starting point."
Round 2: Silverstone (Second overall)
Aside from a few minor tweaks, the car was in the same spec as the opening round. "We didn't want to do anything too drastic and upset the apple-cart," Olly says. The car was on pace and second on a power circuit against a pack of more powerful cars, which was a good result.
Round 3: Knockhill (Second overall)
"My rally experience must have been a help because it taught me to drive on ever-changing surfaces," says Olly when asked about his experiences on Knockhill's tight and twisty circuit-on road-legal tires in the rain.
Round 4: Brands Hatch (Fourth overall)
A win for Olly would have secured an overall victory in the series. So how did he do? "It went pretty well," he responded. "There was nothing wrong with the car but I struggled to get to grips with a track, which was new to me. That first bend is just so deceptive. Every time you drive it you think you can do it faster next time, but self-preservation then kicks in!"
Subaru Impreza
Power Output: 605 Bhp, 722 Bhp (Including Nos)
Engine
2l 16v Quad Cam Ej20 Engine
Closed-Deck Subaru Block
Wrc R-Profile High Wrap Cam Belt System
Modified Oil Pump
Wrc S10 Inlet Manifold, Eight Injector Kit
72 Mm Throttle Body
5.5-Liter Alloy Sump
Oil Catch Tank And Breather System
Subaru S202 Oil Cooler
Goodrich Braided Vacuum Hoses

Internals
Extreme Arrow H- Section Rods
Steel Billet Crankshaft
Omega Ceramic-Coated Flat-Top Pistons 9.75:1 Compression
Parted Sti 4 Cylinder Heads Modified For Lobe Clearance, Fitted With Wrc/Rcms A-Ring Head Gaskets And Gas Rings
Rcms Camshafts Exhaust 270-Degree 1o.5mm Lift,Inlet 290-Degree Duration And O.5mm Lift
One-Piece Nimonic Exhaust Valves
One Piece Stainless Inlet Valves
Uprated Valvesprings
Plasma Nitrided Titanium Spring Caps
Wrc Main And Big End Bearings
Induction
Garret Gt40/88 Twin Scroll Turbo Running 2.1-Bar Boost
I.C.E. Adjustable Boost (1.2 To 2.1 Bar)
K&N Air Filter With 100mm Inlet Trumpet
Rcms High-Flow 100mm Thick Front-Mount Intercooler With Twin-Tube Core 70mm Stainless Steel Intercooler Pipework
Wizards Of Nos Direct-Port Nitrous Kit Set For 100bhp Increase
Fueling
8 X 700cc Injectors
Blueprinted Bosch 044 Fuel Pumps (200-Liter Per Pump)
Sx Fuel Regulators Set At 4-Bar Static Pressure
Goodrich Fuel Feed Pipe
Goodrich Fuel Return Pipe
Rcms Fuel Distribution Block
Fia Spec 28-Liter Rubber/Kevlar Bag Fuel Tank In Aluminum Cover
Vp120 Race Fuel

Engine Management
M800 Motec Ecu With Traction Control, Nitrous Control, Anti-Lag, Paddle Shift Control And Full Data Logging
Exhaust
Wrc Short Runner Ceramic Coated Exhaust Manifold
Tial 45 Mm External Wastegate
3.5-Inch Unsilenced Stainless Steel System With Ceramic Coated Downpipe
Drivetrain
R180 Sti Rear Axle 3.9:1 Cwp And Plated Modena Lsd Differential
Gkn Rally Driveshafts
Torque Line Carbon-Fiber Propshaft
Rcms Six-Speed Subaru Gearbox Casing Modified For Sequential Gearbox System
Six-Speed Modena Gear Kit
Subaru 3.9:1 Front Cwp
Rcms Paddle Shift System
Plated Center Differential With 1:1 Uprated Output Modena Gears
Plated Front Modena Differential
Rcms Spec Triple-Plate Os Giken Clutch And Flywheel
Rcms Hydraulic Light Pressure System
Brakes
Front Ap Racing 355mm Discs And Six-Pot Calipers
Rear Ap Racing Gpn 270mm Discs And Four-Pot Calipers
Ds3000 Racing Pads
Rcms Hydraulic Carbon Hand Brake
-3 Stainless Steel Goodrich Pipe Work And Quick Release Fittings
Bias Pedal Box With Dash-Mounted Adjuster
Quick Change Brake Bias Adjuster On Center Console
Quick-Release Dry Brake Fluid Connection
Suspension
Wrc Spec Exe-Tc Fully Adjustable Dampers With High- And Low-Speed Bump And Rebound Adjustment
350-Pound Front Springs And 325-Pound Rears
Sti Rose-Jointed Rear Lateral Links
Sti Rose Jointed Rear Trailing Links
Exe-Tc Bottom Rose Jointed Upright Bushes
Sti Alloy Front Arms
Sti Quick-Steer Steering Rack
Rcms Adjustable Rose Jointed Arms Front And Rear
Rcms Fully Adjustable Top Mounts
Wheels & Tires
8.5x18 Dymag Carbon/Magnesium Alloys
245/40-18 Michelin Pilot Sport Cup And Toyo R888 Tires
Exterior
Wrc Steel Arches And Skirts
Wrc Front And Rear Bumpers
Wrc Carbon Rear Spoiler With Additional Wing Supports
Sti Alloy Bonnet With 22b Vents
Rcms Carbon Vent
Wrc Front Vent And Rcms Gas Struts
Heated Front Screen
Wrc Non-Heated Lightweight Rear Screen
Modified Front And Rear Inner Arches
Semi-Tubbed Front Arches
Semi Seam-Welded Chassis
Carbon-Fiber Race Mirrors
Motec Data Logging Transponder Mounted In Drivers Wing Mirror
22b Alloy Wing Badge On Front Grille
Interior
Fia Gpn T45 Multipoint Welded-In Rollcage
Motec Digital Dashboard
Defi Turbo/Fuel Pressure Gauges
Carbon Kevlar Recaro Spa Pro Seats
Sabelt Six-Point Harness
Wrc Roller Bearing Single-Piece Steering Column
Momo Steering Wheel
Rcms Sequential Gear Stick With Reverse Lock Out Mechanism
Rcms Steering Wheel Mounted Paddle Shifters
Full Plumbed-In Fire Extinguisher System
Rcms Carbon-Fiber Door Cards

Photo Gallery: Subaru GC8 Impreza - Turbo Magazine



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