STI 04 — Stage 3 ECU Tune
- 183% net increase in power delivery to 295kW
- 140Nm additional torque capacity for improved acceleration
- Enhanced boost control and solenoid management
- Optimised fuel injection mapping for Flex Fuel compatibility
- Drive-by-wire integration for responsive throttle control
- Stage 3 performance calibration for maximum output
This 2004 STI runs a full standalone on Haltech with flex-fuel capability, taking a tired factory EJ25 from 104 kW to 295 kW at the wheels. Torque climbed from 268 Nm to 408 Nm, the result of a complete fuelling overhaul: high-pressure pump, injectors, upgraded boost control hardware including wastegate and solenoids, and drive-by-wire integration.
The calibration was dialled in for E85 and 98 RON flex operation, giving the owner flexibility at the bowser while keeping the engine safe under high load on track days. It's a properly sorted track-focused package built for closed-circuit competition use, not weekend grocery runs.
What does the flex-fuel setup allow on this EJ25?
The calibration supports both E85 and 98 RON pump fuel, with the ECU adjusting automatically based on ethanol content. This gives flexibility at the track without retuning between events.
Why the jump to standalone ECU for a Stage 3 build?
At this power level and with full fuelling hardware, the factory ECU becomes a limitation. The Haltech gives proper control over flex-fuel, drive-by-wire, boost management, and allows safe tuning headroom for 295 kW.
Is this calibration suitable for street use?
This is a competition-spec build calibrated for closed-circuit and off-road use only. Power delivery and hardware are optimised for track conditions, not daily commuting.
Workshop & Dealer Access
Protunes supplies ECU calibration files exclusively to approved workshops, tuners, and dealers throughout Australia. Platform: Haltech.
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