Introduction to the Alfa Romeo 2.0T GME Hurricane Twin-Scroll Turbocharger
The 2.0-liter GME (Global Medium Engine) Hurricane all-aluminum inline-four petrol engine (200 HP and 280 HP variants) featured in Alfa Romeo Giulia/Stelvio and Jeep Wrangler/Grand Cherokee incorporates a cylinder head with integrated exhaust manifold paired with a Garrett / Calsonic Twin-Scroll turbocharger and Electronic Wastegate (E-Wastegate). Furthermore, the engine employs a dedicated liquid-to-air Charge Air Cooler (CAC) integrated directly into the intake manifold plenum.
Twin-Scroll Architecture and E-Wastegate Control
The Twin-Scroll turbine housing separates exhaust gas pulses from cylinders 1-4 and 2-3 into dual isolated scrolls leading to the turbine wheel. The DC-motor driven E-Wastegate delivers instantaneous pressure relief during tip-out and shields the engine from knock at high load. Symptoms and DTCs:
- P0299: Turbocharger Underboost Condition.
- P00AF: Turbocharger Boost Control Actuator 1 Performance.
- P0234: Turbocharger Overboost Condition.
E-Wastegate Adaptation Protocol via WiTECH / AlfaOBD
Following E-Wastegate actuator replacement or turbocharger servicing, an electronic calibration sequence is mandatory:
- Linkage Pre-load Mechanical Setting: Adjust the turnbuckle linkage rod until the position sensor output voltage reads exactly 3.70V (+/- 0.05V) at the closed mechanical stop.
- Diagnostic Calibration: Connect WiTECH 2.0 or AlfaOBD. Navigate to: Engine Control Module -> Miscellaneous Functions -> Wastegate Actuator Learn.
- Cycle Verification: The ECM cycles the actuator through 5 full stroke sweeps to learn hard stop limits and peak motor current thresholds.
Charge Air Cooler (CAC) Coolant Bleeding Procedure
Subsequent to turbocharger or cooling system maintenance, the independent low-temperature CAC coolant loop must be thoroughly purged of air. Entrained air pockets cause Intake Air Temperature (IAT) spikes over 65°C, prompting the ECM to pull ignition timing and taper boost target:
- Attach a pneumatic vacuum coolant refiller tool to the dedicated CAC expansion tank.
- Draw a vacuum of **-0.85 bar** and fill the loop with 50/50 Mopar OAT coolant.
- Command the auxiliary electric CAC water pump via diagnostic tool (CAC Electric Water Pump Purge Routine) for 10 minutes.
Technical Fastener Specs and Torques
- E-Wastegate Actuator Mounting Bolts: 9 Nm.
- Turbine Downpipe V-Band Clamp: 15 Nm.
- CAC Intake Manifold Fasteners: 10 Nm.
Precision calibration of the E-Wastegate paired with complete CAC loop purging ensures full 400 Nm torque delivery and immediate throttle response in Alfa Romeo 2.0T engines.