The Subaru’s Impreza WRX STi is one of those cars. Looking over my notes I see all sorts of things I could write about, but two things keep coming back as I remember driving this no-nonsense, 300-horsepower rocket: instant throttle response and fabulous steering.
Even the slightest touch of your right foot to ETC (Electronic Throttle Control or if you prefer, drive-by-wire) stirs the dual overhead camshafts (which are hollow to save weight) to activate all sixteen valves of the extra-stiff 2.5-liter, turbocharged and intercooled “boxer” engine. The pistons beneath those valves are made of forged aluminum alloy, while the connecting rods that move the pistons are made from forged, high carbon steel. Too, the STi features Subaru’s first-ever use of variable valve timing, dubbed AVCS for Active Valve Control System. The IHI turbocharger is identical to those on Subaru’s World Rally racecars, providing up to 14.5 psi of maximum boost. The STI’s intercooler is 30 percent larger than the one of the “regular” WRX and adds a manually controlled water spray of up to two seconds for a more oxygen-rich charge.
If this mechanical jargon loses you, just know that the above helps produce 300 pound-feet of torque, three hundred, from a four-cylinder motor. And while impressive, it just begins to tell the story of “the black sheep of Subaru.” That’s how T.K. Saito referred to this “most powerful Subaru ever,” during its U.S. press introduction.
Commitment to power