WRX vs.WRX STI engine
4 doors & 6 on the floor
Joined: Feb 2005
Posts: 1,027
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Straight from Subaru Drive magazine (Subaru Drive Magazine: Fall 2003)...
The WRX STi isn't just a WRX with more horsepower, but it does share its rugged, unitized body and chassis with other Impreza models. The chassis is so stiff that it doesn’t need the strut-tower brace used in other performance cars. Beyond the overall chassis, Subaru engineers have analyzed every component to make sure it’s strong enough to be part of a 300-horsepower sedan.
What makes the WRX STi different? Start with the engine itself. Although at 2.5 liters it’s the same size as the engine in other Impreza models, it has a reinforced block to cope with higher internal pressures. Variable valve timing optimizes internal airflow, and the larger turbocharger produces higher boost than the WRX’s. A larger intercooler with a water spray reduces intake-charge temperature. Electronic throttle control – “drive by wire” – and racing technology such as sodium-filled exhaust valves and iridium-tipped spark plugs help handle the heat while also helping the WRX STi engine to qualify as a 50-state Low Emission Vehicle.
A six-speed manual transmission and a larger, stronger clutch mate with an exclusive Driver Controlled Center Differential. The differential offers a choice between computer-controlled power distribution or – when conditions or personal driving style warrant – a driver-selectable manual override. Front and rear limited-slip differentials make sure the all-wheel-drive system gets maximum grip at each wheel.
Special inverted struts increase bending resistance for more accuracy and responsiveness in hard cornering. Stiffer springs make a less forgiving ride, but they’re necessary in such a high-performance car. Quicker-ratio steering gives the driver faster input. Huge Brembo racing-style brakes combine with specially tuned Super Sport anti-lock braking for sure and stable stops.
Acceleration, braking and steering all connect to the ground via 17 x 7.5-inch BBS aluminum-alloy wheels and wide and sticky 225/45 R17 90W Bridgestone Potenza RE070 directional summer-only tires.
No wonder the car is named for Subaru’s high-performance and racing arm – Subaru Tecnica International, or STi. It earned the honor.
4 doors & 6 on the floor
Joined: Feb 2005
Posts: 1,027
Likes: 0
But I'll settle for whoring myself out for the rep points you gave me. 
