300 GTX — Stage 3 ECU Tune
- 33% power increase to 223kW
- 49% torque increase to 255Nm
- Improved throttle response
- Flex fuel capability for E85 and 98 RON
- Enhanced boost control management
- Optimized fuel delivery system
This GTX 300 left naturally aspirated territory behind with a full Stage 3 build centred on a Garrett turbo and Motec standalone engine management. The Rotax powerplant now runs flex fuel capability, backed by high-flow injectors, an upgraded fuel pump, and electronic boost control with wastegate management. Drive-by-wire calibration was refined to suit the new hardware.
The result is 223 kW and 255 Nm at the wheels, up from 167.5 kW and 171 Nm respectively. Gains of 55.5 kW and 84 Nm put this ski firmly in competition territory. The flex fuel calibration allows tuning between pump 98 RON and E85 depending on use, with boost and fuelling tables adjusted accordingly.
This is an off-road and closed-circuit build. The Motec platform gives granular control over all parameters, essential when running forced induction on a platform originally designed for natural aspiration.
Does the flex fuel calibration require switching maps manually between 98 and E85?
The Motec ECU handles fuel content adaptively within the calibrated range. No manual map switch is required, though optimal power on E85 will differ from 98 RON due to fuel properties.
What's involved in a Stage 3 PWC build like this?
Full forced induction conversion: turbocharger, standalone ECU, upgraded fuel system, boost control hardware, and drive-by-wire recalibration. It's a ground-up rebuild of the induction and management system.
Is this file suitable for a stock GTX 300 with bolt-ons?
No. This calibration is specific to the hardware listed: turbo, Motec ECU, injectors, fuel pump, and boost control. It will not run safely on different hardware.
This calibration was developed for a workshop like yours
The Sea-Doo 300 GTX above was calibrated by Protunes for a partner workshop — they did the vehicle work and kept their customer; we did the calibration engineering on the Motec. Add professional ECU and TCU calibration to your workshop without employing a calibration engineer.
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