Getting a grip on the supercharged Scion tC
By Ed Hellwig Email
The first acceleration run is worthless, nothing but front-tire spin and smoke. Easing up the second time around, we bog the engine, miss a shift, and turn in a quarter-mile time that could vote.
You would think we were trying to launch a nitromethane-spewing Top Fuel dragster, but instead we're behind the wheel of a 2006 Scion tC coupe that looks like it could barely chirp the tires.
Ordinary tCs do struggle to grab rubber, but this is no ordinary Scion. Under the hood of this tC sits a centrifugal supercharger developed by Toyota Racing Development (TRD). It's squeezing 7 pounds of boost into the stock 2.4-liter four-cylinder with the help of a revised air intake. Bigger fuel injectors and a remapped engine control unit (ECU) assure an adequate mix of fuel and spark while a TRD exhaust spits out the leftovers.
Still, it's no Hemi Charger, so we continue to rip it down the drag strip in search of a respectable quarter-mile time.
Oldest trick in the book
Superchargers are old, older than cars in fact. They work on a pretty simple idea: instead of relying on the engine to suck in its own air, you force-feed it with compressed air. By stuffing in more air, you can add more fuel and the result is more horsepower.
Sounds simple, but it's easy to screw up. That's why aftermarket superchargers rarely come with a warranty.
With TRD's setup, the tC retains its 3-year/36,000-mile factory drivetrain warranty as long as everything is dealer-installed, a 6-to-8-hour process by Toyota's estimates. Combine that with the $3,200 cost of the supercharger and you're looking at around $3,500 minimum on top of the tC's $16,200 base price. Do the work yourself and the warranty drops to 12 months or 12,000 miles.
Second time around
A few more runs and we're finally getting the hang of the tC's power. Its supercharged thrust is instant, so the tC takes a restrained foot to keep it hooked up. Even with our test car's optional 18-inch EMX wheels and Pirelli P Zero Nero tires (225/40R18), traction is a problem.
We shouldn't be surprised. Adding the supercharger gives the tC a solid 200 horsepower at 6,200 rpm according to TRD. That's 40 more horses than the stock tC and 200 rpm higher on the powerband. Torque is up, too, from 163 pound-feet at 4,200 rpm to 184 lb-ft at the same speed.
Not exactly Neon SRT-4 numbers, but they do stack up pretty well against the 2006 Honda Civic Si, which puts out 197 hp and 139 lb-ft from a 2.0-liter four-cylinder.
The TRD way
With so many aftermarket systems already available for the tC, we ask Gary Boler, business operations manager at TRD, what makes this system different. "We designed this system with three major goals in mind: maximum power, clean emissions and refined operation," he says.
Since there are aftermarket turbo kits that boost the tC's output by considerably more than 40 horsepower, we ask why TRD didn't go the turbo route. He mentions the tC's close-coupled exhaust catalyst that makes a turbo difficult, if not impossible, to fit. "We wanted to keep the installation simple for our dealers. Plus, a turbo generates a lot more heat under the hood."
We didn't need a smog test to confirm the cleanliness of tC's emissions. The system earned an exemption from the strict California Air Resources Board (CARB) making it legal in all 50 states.
Scion smooth
Other supercharger setups might deliver more power, but they would be hard-pressed to match TRD's setup for refinement. Start it up and you barely hear the compressor. Other than a faint flutter off idle and a couple of quarter-panel badges, you would hardly know there was anything different under the hood. Even the TRD exhaust is relatively quiet.
With no other driveline modifications, the supercharged tC drives just like any other Scion tC. It idles smoothly, builds power progressively, and would probably get decent mileage if we didn't have our foot in it the whole time.
TRD offers a high-performance clutch, but the stock unit handles the extra power just fine. Same goes for the five-speed shifter. If you have an automatic-equipped tC, you're out of luck since the TRD system is for manuals only.
The larger wheels and tires give our test car good grip, and the optional Hotchkis strut tower bar stiffens up the front end slightly. With the help, our Scion weaves through the slalom course at 66.3 mph. Fast, but not quite as fast as the Civic Si's 67.8-mph run through the same set of cones.
Last chance
With its big torque advantage over the Civic Si, we expect the Scion to be quicker in a straight line but the Honda has a couple advantages. One is a six-speed gearbox that allows it to run shorter gears to keep the revs up. The other advantage is the Si's standard limited-slip differential which allows the Honda to get its torque to the pavement more efficiently.
After a few more runs down the drag strip, we nail the launch and click off a 7.2-second 0-to-60 time and a 15.1-second quarter-mile. Solid times that are identical to the numbers we ran in the Civic Si. With a limited-slip splitting up the torque, there's no doubt that the tC would be quicker, but as of right now, Scion doesn't offer one.
The money matters
Being in the same drag-strip bracket as the Civic isn't a bad place for the Scion, but keeping a supercharged tC in the same price range as the Si isn't easy. Between the cost of the supercharger, installation and a handful of options, our test car has a sticker price well over $26,000. With the Si going for a mere $19,990 for everything but a navigation system, $26K for a 2006 Scion tC Supercharged is hard to swallow.
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Video also available @ Link:
http://www.edmunds.com/insidel...08776
