STI — Stage 3 ECU Tune
- 183kW power increase enabling 43% output gain on premium fuel mapping
- 140Nm torque uplift with 52% improvement across performance band
- Flex fuel capability for E85 and 98 RON fuel optimization
- Advanced boost control and solenoid tuning for enhanced responsiveness
- Fuel system optimization with high-pressure pump and injector calibration
- ECU-integrated engine management refinement for seamless power delivery
This 2004 STI was built for track use with a complete hardware overhaul: upgraded fuel system, high-pressure pump, larger injectors, boost solenoids, wastegate, and drive-by-wire conversion. The Haltech standalone was the natural choice to manage flex fuel capability and the increased airflow.
The calibration prioritises drivability alongside the big numbers. Flex fuel allows the owner to run anything from 98 RON pump fuel to E85, with the ECU adjusting ignition and fuelling on the fly. The result is 295 kW at the wheels and 408 Nm of torque, up from 104 kW and 268 Nm respectively.
This is a serious track build. The torque curve is broad enough to make the car usable, but the hardware and tune are both intended for closed-circuit competition use only.
Why Haltech for this build?
Haltech offers excellent flex fuel support and the granular control needed for a full Stage 3 build. It handles the drive-by-wire conversion cleanly and gives plenty of headroom for future changes.
What's the advantage of flex fuel on a track car?
Flex fuel lets the tune adapt to whatever's in the tank—98 RON for a street drive or E85 for maximum knock resistance and power on track. It's practical for a car that sees mixed use between transport and competition.
Is this tune road-legal?
No. This is a full competition build intended for closed-circuit use only.
Workshop & Dealer Access
Protunes supplies ECU calibration files exclusively to approved workshops, tuners, and dealers throughout Australia. Platform: Haltech.
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