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Home / ECU Remapping / BMW X3 35i
N55 Engine

BMW X3 35i

F25

The F25 X3 35i with the N55 straight-six. A practical SUV that gains meaningful performance from ECU remapping with strong mid-range torque.

302 Stock BHP
390 Stage 1 BHP
420+ Stage 3 Ceiling
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BMW X3 35i F25
Performance Stages

N55 Tuning Stages

All power figures are average estimates based on typical results. Actual gains depend on vehicle condition, fuel quality and supporting modifications.

01

Stage 1

360-390 bhp

Software only. No hardware changes required. Custom ECU calibration on fully standard engine.

  • Custom map written in-house
  • No additional parts needed
  • Fully reversible
02

Stage 2

390-420 bhp

Calibrated for bolt-on modifications. Downpipe, intake and supporting hardware.

  • Requires supporting hardware
  • Mapped to your specific mods
  • Data-logged and validated
03

Stage 3

420+ bhp

Full custom calibration for serious builds. Hybrid turbos, uprated fuelling and bespoke mapping.

  • Hybrid or upgraded turbo
  • Uprated fuel system
  • Bespoke build calibration

Ready to Tune Your X3 35i?

Get in touch to discuss your build. Every map is written in-house and tailored to your car.

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