In reaction to those who deemed the previous generation of Imprezas as "bugeye", "peanut eye", or absolutely hideous, Subaru unveiled a bold new direction for 2006. The latest edition of the WRC-developed stomper debuted with a triple-section grille that represents the cross-section of an airplane (the historical background of parent company Fuji Heavy Industries) and a pair of headlights that looks strangely similar to BMW's latest designs.
Luckily for all of us speed-chasing rally wannabes, what didn't change was the heart and soul of the WRX. Turbocharged four-cylinder boxer engine that rumbles as only a Subaru can? Still present. Confidence inspiring all-wheel-drive system? Check. Six-speed transmission with electronic driver controlled center differential? Here to stay. In fact, the biggest change for the Impreza WRX STi, besides looks, is the revised aerodynamics of the new body.
Blitz, the aftermarket manufacturer extraordinaire, is quite familiar with the WRX STi model. Just take a look at the Turbo June 2005 cover car, the Blitz twin-turbo STi. Featuring two K3-330R turbos and a beautifully fabricated maze of plumbing, the Tokyo Auto Salon demo car shamed Skyline GT-Rs, Lancer Evolutions and Silvias in the quest to garner stare after stare.
Built more for the street than the shows, this 2006 Subaru Impreza WRX STi Spec C has been tuned by Blitz with all the tricks and research data compiled from past projects. The Spec C moniker denotes that this STi was born as the fastest, most hardcore vehicle that Subaru produces. Race ready, the Spec C carries less weight, larger coolers and extra chassis reinforcement over the standard STi model. STi Spec C models can be easily spotted by their roof scoops and dark interior fabric, neither of which is available with the standard STi. Before you run down to your local Subie dealer with cash in hand keep this in mind: the Spec C is a JDM model only and will probably never be sold here in the US. Yup, we got screwed again.
Although USDM STi models use a large 2.5-liter engine, Japanese STis continue to use the high-revving 2.0-liter EJ207 motor. Completely different than the open-deck 2.0-liter engines found in standard '02-'05 USDM WRXs, the JDM EJ207 features a twin-scroll turbo, AVCS, a semi-closed deck design and a higher 8,000 rpm redline. The stock output for the JDM STi is rated at 276 hp at 6400 rpm and 311 lb-ft at 4400 rpm.
When beginning development on this Spec C, the first thing Blitz did was to rip out the stock turbo system. Boost is now fed by a Blitz K3-450R #8 turbocharger kit. Featuring a turbo developed with KKK Turbo of Germany, the prototype kit includes the up-pipe, downpipe, Blitz D47D wastegate and all required fittings. The stock intake tube has been retained by Blitz and is fit with a Sonic Power Air Cleaner intake system.
One of the byproducts of the horizontally opposed engine is the tangled turbo system. With exhaust ports on opposite sides of the engine, and only one turbo to feed, the exhaust manifold must snake around to merge into one point. Subaru's design has been to place the turbocharger behind the engine and utilize a short plumbing top-mount intercooler. But, to resist heat soak in high power applications, a tiny intercooler placed right on top of the engine is not the best idea.
Blitz uses their front-mount LM Intercooler kit on this Spec C, and the multiple tubes under the hood are a dead giveaway. Also helping keep the car cool is a Blitz Racing LM Radiator and a higher-pressure radiator cap. With a set of Blitz Racing spark plugs installed, the Spec C's engine tuning was considered finished. Blasting out of a Blitz Nur-Spec C-Ti exhaust system, the Subaru was tuned with a Blitz R-FIT fuel controller, Blitz SBC i-Color boost controller and Blitz A/F Ratio Analyser. The final output is now a solid 358.3 hp at 6190 rpm and 330.5 lb-ft at 5150 rpm.
Even with the increased power levels, the entire drivetrain remains stock, down to the clutch and shifter. However, upgrades have been made in the interest of track readiness. The stock Brembo four-piston front and two-piston rear fixed caliper setup has been praised over and over for its stopping power and firm modulation. Blitz has increased the bite and temperature range of this STi's system with the addition of Blitz Pagid RS4-2 front and Blitz MR-3 rear brake pads. Providing the pavement stick is a set of Dunlop Direzza Sport Z1 tires, sized 245/40/18 all around. The already capable Spec C suspension has been dumped in favor of prototype Blitz Damper ZR coilovers, fit with a stiff 12 kg/mm front and 8 kg/mm rear spring rate. The Blitz coilovers feature full dampening adjustment, ride height adjustment and front upper camber plates
To those who aren't in the know, the STi appears every bit like the stereotypical street racer machine with its collection of wings and scoops. But Subaru's STi is no fake. Homologated for Group N rally use, the STi Spec C features an intercooler-feeding hood scoop, sculpted side skirts, front undertray, rear diffuser, roof scoop and box wing. Blitz's only addition is the Flex front spoiler, color matched to the STi's factory white.
Keeping true to Subaru's original recipe, Blitz has tuned the new 2006 Impreza WRX STi Spec C according to design. No stereos, no fiberglass and no unnecessary junk. Just a tightening of all the bolts and a double dose of extra power and speed. Every car should be so lucky.