For all intents and purposes, the 2009 Subaru Impreza WRX STI Spec C should not exist. The fact that we are even writing about the Spec C — a limited-edition, significantly tweaked evolution of the Impreza WRX STI — is a miracle.
Plans for the Spec C were nearly scrubbed late last year when Subaru ended its 20-year involvement in the World Rally Championship after the recent, massive decline in worldwide sales caused the bosses to radically rethink the company's motorsports program. In an emotional press conference just before Christmas, company president Ikuo Mori fought back tears as he told a stunned gathering of media, "Our decision was in response to the economic downturn. We had no choice."
When decisions like this are made, it's normally the limited-edition models like the 2009 Subaru Impreza WRX STI Spec C that get axed first. But not this time. Subaru wants to send a message to the market and its thousands of concerned fans. It's telling us that the company might have had to tighten its belt, but it has not forgotten who it is.
Why Build 1,000?
The 2009 Subaru Impreza WRX STI Spec C is Subaru's most extreme model, the best of the best. That's why Subaru is building only 1,000 units, 100 of which will be sent overseas (mainly to Europe) for various privateers in national-level rallying. We can expect a dozen or so to eventually surface here in the U.S. but not for some time. If the truth be known, the total of 1,000 has special significance, as it's the minimum number a carmaker must produce to homologate a car for FIA Group N rallying, a class for standard production vehicles.
This is not the first time Subaru has tweaked an STI. Subaru's back-room boffins got busy beefing up the WRX when they first added the STI badge to a WRX in 1994, creating the STi Type RA. They basically launched a Type RA every year for the first-generation Impreza (GC8) and then continuing with the Spec C when the second-generation Impreza (GDB) was launched in 2002.
Using a modified version of this production-based package, Subaru won three consecutive WRC constructor's titles from 1995-'97 plus three driver's trophies: for Colin McRae in 1995, Richard Burns in 2001 and Petter Solberg in 2003. This Spec C is the first in hatchback form, as it's based on the new third-generation (GRB) Impreza.
The Racer's Shopping List
While Petter Solberg won't be piloting the new 2009 Subaru Impreza STI Spec C in WRC events, this new Spec C is an exponential improvement over the base-model WRX STI. Just one lap of the short 0.8-mile south track at Honda's Twin Ring Motegi complex, two hours north of Tokyo, was enough to highlight the heightened abilities of this car. It's simply phenomenal. Compared to the stock STI, the Spec C is a full second faster, recording a 57.9-second lap versus the 58.9-second time for the standard car.
The upgrades from STI (the high-performance division of Subaru, which both sells aftermarket hardware and prepares specialty cars like this one) reads like a pre-race checklist for a one-off supercar: specially tuned ball-bearing turbo; spray-type water cooling for the intercooler; high-capacity fuel pump; high-capacity hydraulic pump for power-assisted steering; recalibrated suspension with unique dampers, coil springs and bushings; mechanical limited-slip differential; four-piston Brembo brake calipers; and Bridgestone Potenza RE070 tires.
Few carmakers go so far with high-performance upgrades for a car that can basically be bought from a factory dealership.
Hiding the Hierarchy
Strangely enough, Subaru appears to have been very scrupulous about ensuring there are no badges of emblems on the new car that would identify it as a Spec C. In fact, you can hardly tell the car apart from a WRX STI. The exteriors of the two cars are almost identical, and you have to look beneath the fenders to see the Spec C's telltale, gold-color Brembo brake calipers and the substitution of Bridgestone Potenza RE070 tires for the stock RE050A rubber.
So why not use unique badges for the Spec C? Chief engineer Hiroshi Mori lets on to us that the Subaru bosses (in all their wisdom) decided to not use badges to differentiate among the three Impreza STI models: the STI, the Spec C and the A-line with its five-speed automatic. The reason? Apparently it causes a "weird hierarchy" among the owners. In fact, some owners of the last-generation Spec C actually removed the STI badge, forcing onlookers to focus on the Spec C emblem.
It's also nearly impossible to distinguish the 2009 Subaru Impreza WRX STI Spec C from within the cockpit. If it weren't for the optional Recaro seats with red stitching, you'd think you were in a standard STI. Until you floor the throttle and take your first corner, of course. That's when the penny drops, and you realize what all those high-spec modifications are all about.
Water Is the Secret Weapon
The Spec C uses the 2.0-liter version of the boxer-4 instead of the 2.5-liter boxer-4 we see in the U.S. because the smaller engine circumvents Japanese tax laws. Meanwhile the Spec C's ball-bearing turbo not only improves reliability but also quickens response since there's less mechanical friction. As a result, the Spec C feels faster than the STI, even though the engine's output is no different — 304 horsepower at 6,400 rpm and 311 pound-feet of torque at 4,400 rpm.
Part of the Spec C's advantage comes from light weight, as the use of a smaller battery, aluminum hood and forged-aluminum 18-inch wheels (not to mention discarding the spare tire) combines for a 66-pound reduction. But the Spec C's secret advantage over the conventional STI is water. Just like the first WRX STI sold in the U.S., the Spec C has a device to spray water on the air-to-air competition-spec intercooler.
On the day we tested the Spec C at Motegi, the mercury hovered around 90 degrees F and humidity cleared 60 percent — far from ideal conditions for making horsepower. But regularly spraying a fine mist of water on the intercooler helps stabilize engine intake temperatures, so power output becomes more consistent. This is especially important in this application, as intake temperatures for the boxer-4 can reach upward of 150 degrees F (perhaps not surprising when you consider that the intercooler sits right on top of the engine). The constant shower reduces intake temperatures to around 100 degrees F.
Slicing 50 degrees off the engine's operating temperature means a difference of 24-25 hp and around 25-30 lb-ft of torque, the STI engineers tell us. It's not that the Spec C has more power or torque; it's just that the water improves the effect of the intercooler, while the ball-bearing turbo produces quicker throttle response.
Control the Geometry
The last-generation Spec was criticized because it suffered from excessive squat and body roll while accelerating out of corners, and also because it didn't feel as precise in the steering department as many enthusiasts would like. The makeover began with the adoption of the new SI chassis architecture for the Impreza, and the STI Spec C also includes a stiffer rear antiroll bar, stiffer dampers and springs, and the substitution of a mechanical limited-slip differential for the rear wheels in place of the standard Torsen unit.
You'd expect the car to bounce your eyeballs loose as soon as you hit anything that even resembles a bump, but the Spec C offers a surprisingly compliant ride while resisting body roll or the urge by the rear end to squat coming out of fast corners. The mechanical LSD assists in generating massive amounts of rear grip, too. Overall, our Spec C had far more body control in the corners, accentuating the stick of the Potenza RE070 tires.
The substitution of a mechanical limited-slip differential for the rear axle in place of the STI's Torsen LSD also produces a greater feeling of accuracy in the steering, as it's now more responsive to small inputs.
Speed You Can Use
Unlike the last generation of the Spec C, which did without all of its acoustic insulation in the process of reducing overall weight by 200 pounds, the 2009 Subaru Impreza WRX STI Spec C is far more usable on the road.
It is definitely noisier in terms of road and engine noise, but it has not sacrificed ride comfort, so long trips should be bearable. Only the Recaro seat is a problem, for while it has plenty of the support you need during hard cornering, it's not ergonomically designed for long hours at the wheel. After two hours on a highway, our lower back was crying out for a stretch.
While finding the limits of cornering grip in the new-generation STI can be a challenge, the Spec C tells you when the limit of adhesion is being reached. And being able to get closer to the Spec C's limits, but staying within your own, make this car a lot more fun — and safer — to chuck around than a stock STI.
It's just too bad it won't be widely available in the U.S., because its base price of $38,000 makes it a bargain. It's true, this car should not exist. But, hey, are we glad that it does.
The manufacturer provided Edmunds this vehicle for the purposes of evaluation.
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