We ran our fingers across the top of the BRZ’s grille, slowly opened its hood, and … nothing. There’s a cold-air intake, but no turbocharger fitted onto the exhaust manifold. This pearl-white car isn’t a Subaru BRZ STI but instead a Subaru BRZ tuned by STI, and there’s a big difference between the two.
It’s all about tension control
Limited-edition Subaru models badged tS (which stands for tuned by STI) have been on sale in Japan for some time now, starting with the Legacy tuned by STI in 2005. The Subaru BRZ tS and other tS models demonstrate what Subaru Tecnica International (STI) says is its core competency. This it describes as “tension control,” also known as tweaking, tightening, and dialing in a chassis.
While the Subaru BRZ has one of the best-balanced chassis we’ve driven, the tS benefits from a range of modifications. The chassis structure is enhanced by a unique, front strut-tower brace, underbody stiffeners that compress slightly under loads, and a rear subframe support. The suspension gets stiffer springs that deliver a ride height that’s lower by four-tenths of an inch, plus sportier dampers and harder bushings for the anti-roll bars. The cast-aluminum 18-inch Enkei wheels are wrapped in Michelin Pilot Super Sport tires, and you’ll find Brembo brakes. Even the driveshaft has a larger diameter.
Tuning in the STI way
The STI engineers like to dive into what the parts actually do. The driveshaft’s added girth means it’s more rigid by 26 percent, which should make acceleration feel crisper and more linear through the range of engine rpm and also help the six-speed manual transmission shift slicker. The front anti-roll bar’s bushings are more rigid to help reduce steering hysteresis. The front strut-tower brace has a rod-end joint in the middle, so when one side of the front suspension moves longitudinally after a jolt through a front wheel, the other side doesn’t reciprocate, which helps maximize the contact patch from the front tires at all times.
The STI engineers give us detailed descriptions of cornering, maneuverability, and even yaw rates, feeding information through a Japanese-to-English translator who’s constantly getting hung up on the convoluted technical terms. Then comes something about the total effect of the changes that’s easy to grasp, albeit in poor English: “Whoever drives, wherever they drive, it makes you feel fine and that you’re good at driving.”
Driving in the STI way
We walk into the pit lane, open the door to the white 2015 Subaru BRZ tuned by STI, and get in. No steering wheel. We get out, walk back around to the car’s right side, open the actual driver’s door, and get in.
There are STI badges on the steering wheel, shift knob, and ignition switch. As we speed out of the pit lane while shifting southpaw and pull onto Suzuka Circuit, we feel no differences in acceleration and gear changes brought about by the bigger driveshaft. (No surprise there, really.) At the end of the long front straight, we approach Turn 1, tap the brake pedal, and turn the BRZ tS’s steering wheel.
The turn-in action is sharper, the steering effort feels heftier, and there’s a little less delay between our movements and the car’s response. The Subaru BRZ tS stays flat through the corner, its Michelin Pilot Super Sport tires softly squealing. By the time we exit the corner, the words “uh oh” haven’t flashed before our eyes once. So we speed up, brake less, and pitch the car hard into a challenging series of esses. The BRZ tS shifts its weight around organically as it transitions between tight left and right turns. Doing what we’re doing at the pace at which we’re going, a stock BRZ would be sideways.
What’s going on in the engine room?
Once we’re back on a straightaway, the tS feels much the same as a bone-stock 2015 Subaru BRZ. The acceleration is weak, and the naturally aspirated 2.0-liter Subaru flat-four is howling in a dreadful, metallic way. A turbocharger would add power and also act as a muffler. At the far end of the track, we ease the BRZ tS into a long, long left called the Spoon Curve. As we get deeper into the turn, the BRZ tS leans more and more to the right. With a quick left snap of the steering wheel, the tires break loose and the BRZ tS slides, gliding until its right-rear tire rubs the curbing on the track’s outside edge. Then we balance out the BRZ tS and start down the really long back straight, the flat-four wailing.
Subaru Tecnica International heard about our desire for a Subaru BRZ STI, but it decided not to listen and has teased us instead with the tS. But in the heads of the engineers at Subaru’s skunkworks, added power won’t improve the BRZ because the BRZ isn’t about power; it’s all about handling. So even though a Subaru BRZ STI concept car will be showcased at the 2015 New York International Auto Show, there’s no turbocharged Subaru BRZ STI scheduled to be built in the foreseeable future.
While the Subaru BRZ tS isn’t exactly what we wanted, it’s what we’re going to get. According to what Subaru tells us, we should see a BRZ tS in the States within the next two years. Which is what makes the Subaru BRZ tS both irritating and intoxicating. It’s still short of our dream BRZ, but the tS is notably better and more capable than the car on which it’s based. Fortunately, we love a good tease. Done right, a tease is equally irritating and intoxicating. It seduces you, lures you closer, and convinces you that you’re about to get everything you wanted. Then you get smacked with disappointment to take you back to reality, but the taste is enough to keep you hooked.