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Subaru Intelligent Drive (SI-DRIVE)
iIntelligent (push down on the knob) – smoothness
  • Improved drivability in inclement weather – the engine is less sensitive to movement of the accelerator pedal
  • Smoother operation in traffic, with moderate power delivery
  • Increased fuel economy by up to 10 percent
  • Well-balanced performance
Sport (turn the knob counterclockwise) – linearity
  • Linear power delivery – engine response is almost in direct proportion to accelerator pedal movement
  • Quick throttle response
  • Ideal for day-to-day, all-around performance driving
  • Fun-to-drive feel – to help make the driving experience a personal adventure
s sharpSport Sharp (turn the knob clockwise) – responsiveness
  • Rapid power delivery – engine response reaches 100 percent with approximately 54 percent accelerator pedal movement
  • Added performance edge (close to the feel of an Impreza WRX STI)
  • Quicker throttle response
  • Quicker engine power delivery
  • Greater torque at lower engine speeds
  • For exhilarating, maximum-performance driving


As a student studying the internal- combustion engine, Toshio Masuda foresaw a time when engines would be able to change characteristics without replacing systems within them. Later, as Project General Manager of Legacy and Outback for Subaru, he found support for his ideas, and the end result is SI-DRIVE – an engine control that electronically alters how an engine operates.

SI Display
The multifunction display window in the instrument panel shows the selected SI-DRIVE mode.

Today, SI-DRIVE is found in 2008 Subaru Legacy and Outback models with turbocharged and six-cylinder engines. This feature allows the driver to manage the vehicle’s electronic engine and automatic-transmission controls by switching between three modes.

SI-DRIVE’s purpose is to maximize engine performance, control, and efficiency. As conceived by Mr. Masuda, SI-DRIVE has the effect of giving a vehicle three different engines in one.

The modes are selected by a knob located behind the shifter, and they’re marked [I] Intelligent, [S] Sport, and [S#] Sport Sharp. (A Sport Sharp button is added to the steering wheel for 2008.) The selected mode is shown in the multifunction display window in the instrument panel along with a representation of the corresponding torque curve.

Choosing a mode sends signals to the vehicle’s body control module. From there, wiring carries signals almost instantaneously to the engine’s and automatic transmission’s electronic control units. The SI-DRIVE settings change the control units’ programming (mapping).

SI-Drive Control System

Programming changes modify engine torque characteristics by adjusting how engine and transmission components function. These components include the electronic throttle, fuel delivery system, ignition, turbocharger wastegate, and automatic transmission response.

SI-DRIVE modes deliver three distinct types of driving.

Intelligent: With its moderate power delivery and smooth drivability, this mode is ideal for around-town driving and for difficult driving conditions such as slick roads or loose surfaces. It is the most fuel-efficient of the three modes.

Model 2007 2008
Legacy 2.5 GT Limited Sedan yes yes
Legacy 2.5 GT Limited Wagon yes model not available
Legacy 2.5 GT spec.B Sedan yes yes
Legacy 3.0 R Limited Sedan model not available yes
Outback 2.5 XT Limited Wagon yes yes
Outback 3.0 L.L.Bean® Edition Wagon no yes

Sport: This mode is versatile, providing linear acceleration that is as ideal for freeways and suburban streets as it is for climbing mountain roads.

Sport Sharp: Delivering maximum driving enjoyment, this mode is ideal for tackling twisting roads and for confidently merging or overtaking other vehicles on the highway.

The SI-DRIVE system can sense when a potential engine or transmission problem may exist, and it will react to help prevent damage.

For example, if the CHECK ENGINE warning light/malfunction indicator light illuminates while the engine is running, SI-DRIVE automatically resets to Sport mode. When the light is on, changing to either Sport Sharp mode or Intelligent mode is not possible.

Display Components

Also, if the temperature of the engine coolant increases to the point of possible overheating, selection of the Sport Sharp mode is not possible. If the selector is in Sport Sharp when engine temperature reaches a certain point, the system automatically resets to the Sport mode.

Similarly, the SI-DRIVE selectors in Legacy and Outback models with 3.0-liter engines automatically reset to Sport mode when engine oil temperature increases.

SI-DRIVE enhances the environmental friendliness of Subaru vehicles while making available high-performance driving capabilities.

Thanks to Toshio Masuda’s dream of being able to change an engine’s characteristics, SI-DRIVE enhances the environmental friendliness of Subaru vehicles while making available high-performance driving capabilities. Providing three engines in one, this advanced technology allows a driver to adjust the vehicle to appropriately embrace any driving situation and his or her own driving style.