SI-Drive 2008+ STi Explained:

SI-Drive Intelligence

The SI-DRIVE system is integrated into the Engine Control Module (ECM). SI-DRIVE enables three distinctively different modes of vehicle performance characteristics by regulating the ECM and by fine-tuning the Electronic Throttle Control system. The three modes are:

• Intelligent [I]
• Sport [S]
• Sport Sharp [S#]

With Intelligent mode selected, the system reduces engine torque and maximum power and switches to a more relaxed throttle response curve. Intelligent mode can provide smoother response while commuting in traffic. In addition, Intelligent mode complements the low-traction-surface driving safety provided by the All-Wheel-Drive system.

Selecting Sport mode provides quick throttle responses and powerful, linear acceleration, making it ideal for everyday sporty driving.

In Sport Sharp mode, SI-DRIVE modifies the engine’s electronic throttle mapping to deliver lightning-quick throttle response. As its name might suggest, Sport Sharp mode enhances the performance feel of the car and is ideal for tackling twisty roads and for track driving situations.

What’s the lay of the land? What kind of weather are you having? What’s traffic like out there? (Sounds like the morning weather and traffic report.)

Confused as to which of the WRX STI SI-DRIVE, DCCD, and VDC settings to use? We thought that might be a problem at first – at least until you’ve had some experience with the car. After that, you’ll have your own preferences.

For starters, the chart below has some suggestions for different types of weather and/or performance driving.