325i E90 — Stage 3 ECU Tune
- 265% increase in power output to 265kW
- 234% increase in torque to 277Nm
- Optimized boost control for reliable 32psi operation
- Enhanced fuel delivery via high-pressure pump and upgraded injectors
- Improved thermal management with air-to-air intercooler
- Drive-by-wire ECU management for precise throttle response
This E90 325i runs a dry sump S54 with non-VANOS Schrick cams and a GTX45 turbo, built for circuit use. The Maxxecu calibration manages 2.2 bar through boost control solenoids with E85 fuelling backed by a high pressure pump and upgraded system. The TH400 transmission handles torque delivery.
Result was 265 kW at the wheels with 277 Nm recorded. The torque figure stays modest given the non-VANOS setup and the TH400 driveline, but the package is sorted for repeatable high-rpm work. Calibration focused on safe knock margins and consistent boost control across the circuit lap rather than peak numbers.
Why is torque relatively low for a GTX45 turbo at 2.2 bar?
The non-VANOS camshafts and dry sump S54 setup sacrifice low-end torque for high-rpm breathing. The TH400 transmission also influences driveline losses measured at the wheels.
Is the Maxxecu platform common for S54 turbo builds?
Yes, it's a reliable standalone option for forced induction S54s, offering full control over boost, ignition, and E85 fuelling without OEM ECU limitations.
What's the intended use for this build?
Circuit and closed-course competition. The dry sump, TH400, and calibration priorities are all aimed at sustained high-rpm operation off-road.
Workshop & Dealer Access
Protunes supplies ECU calibration files exclusively to approved workshops, tuners, and dealers throughout Australia. Platform: Maxxecu.
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