Tuning · BMW X4 M40i (G02)
X4 M40i
B58 Gen 2
The X4 in M40i form with the Gen 2 B58 underneath. Hand-calibrated from Stage 1 to a fully bespoke big-turbo build. Choose your package, send your build to Samuel, and get a tune that fits the way you actually drive.
Engine
B58 Gen 2
Stock
374 bhp · 500 Nm
Stage 3 ceiling
374 bhp
About this tune
The G02 X4 M40i (2018-present) is the coupe-SUV variant of the X3 M40i, same B58 Gen 2 drivetrain, same MG1CS003 ECU, in a lower-roofline body with the same xDrive system. Stock is 374 bhp / 500 Nm. The X4 M40i is the rarer of the two SUV variants in the UK; tuning works identically to the X3 M40i and uses the same map.
BMW X4 M40i tuning
Choosing the X4 M40i over an X3 was a styling decision, and tuning it follows the same logic: the G02 coupe-SUV already trades a little practicality for attitude, so giving it the performance to match feels natural. It is the rarer of BMW's two mid-size M40i SUVs in the UK, but mechanically nothing about it is exotic, sharing the Gen 2 B58, ZF eight-speed and xDrive with its squarer sibling, along with the same appetite for calibration.
Stock, the X4 M40i produces 374 bhp and 500 Nm. Samuel's Stage 1 map reworks that to 440 bhp and 680 Nm with no parts fitted, and because xDrive shares the load across both axles the gain is all usable, wet or dry. Owners who fit a downpipe and intake step up to Stage 2 and its 480 bhp and 700 Nm target on the unchanged factory turbo.
As with every Gen 2 B58, serious hardware takes the ceiling to roughly 1,000 bhp via hybrid or full-frame turbo conversions. The G02 is tuned without leaving your postcode: the calibration arrives in your bootmod3, MHD or MG Flasher account, usually well inside 24 hours, you flash through the OBD socket, and the saved stock file means the whole exercise can be undone before any dealer appointment.
Configurator
Build your X4 M40i tune
Choose your stage — Stage 1, Stage 2 or Stage 3 — add the options that fit your car, and send the full build to Samuel for a custom remote remap. He'll quote, schedule, and personally calibrate within 24 hours of confirmation.
Add a stage or add-on
£0
Engine guide
BMW X4 M40i tuning, stages, hardware and what to expect from the G02 B58 Gen 2
The G02 X4 M40i runs the B58 Gen 2, the revised 3.0-litre single-turbocharged inline-six shared with the X3 M40i (same drivetrain, coupe-SUV body). From the factory, BMW set the X4 M40i at 374 bhp / 500 Nm; the hardware ceiling sits considerably higher. BMW X4 M40i tuning with Samuel applies the same Gen 2 Stage 1 / Stage 2 map family used on the X3 M40i, same calibration, same hardware, different body style.
Stage 1
440 bhp · 680 Nm
No hardware required. The MG1CS003 DME is flashed via the OBD port. BMW X4 M40i Stage 1 unlocks 440 bhp and 680 Nm from the OEM hardware (up from 374 / 500 stock). The BMW X4 M40i G02 tuning starting point, the most cost-effective change you can make to BMW's coupe-SUV performance variant.
Every X4 M40i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW X4 M40i tuning done correctly accounts for the G02 chassis weight, xDrive calibration and UK fuel quality; the map is reviewed against your data logs after the first flash and revised before sign-off.
Compatibility
Platform and hardware compatibility
Bootmod3 (BM3)
Full B58 Gen 2 support on the MG1CS003 DME across every Gen 2 chassis (M340i, M440i, M240i G42, Z4 M40i, X3/X4 M40i, Supra 3.0). OBD-port flashing, realtime monitoring via the BM3 app. The most widely used platform for B58 Gen 2 tuning.
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MHD
Full B58 Gen 2 support. Suitable for Stage 1 and Stage 2. Strong data-logging toolset and active community support.
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MG Flasher
Full B58 Gen 2 support. Clean interface and reliable flash process. A common alternative to BM3 for owners who prefer the MG ecosystem.
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xHP Flashtool
Compatible with the ZF 8HP gearbox fitted to every B58 Gen 2 chassis. Gearbox calibration matched to the ECU map, strongly recommended at Stage 2 and above where torque jumps significantly. Available as an add-on.
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ECU: MG1CS003 DME across all B58 Gen 2 production. Accessible via OBD for Stage 1 and Stage 2; bench-flash only required for some Stage 3 hybrid setups.
X4 M40i specs & stage targets
BMW X4 M40i tuning at a glance
- Engine
- B58 Gen 2
- Body styles
- G02 SUV Coupe
- Chassis codes
- G02
- Production
- 2018–2025
- Drivetrain
- xDrive
- Gearbox
- 8-speed ZF automatic
- Stock output
- 374 bhp · 500 Nm
- Tuning ceiling
- ~1000 bhp on the right hardware
| Stage | Target |
|---|---|
| Stage 1 | 440 bhp · 680 Nm |
| Stage 2 | 480 bhp · 700 Nm |
| Stage 3, Hybrid Turbo | 550-1000 bhp depending on spec |
| Stage 3, Big Turbo Kit | 550-1000 bhp depending on spec |
FAQ
X4 M40i tuning — frequently asked questions
No. The G02 shares its complete drivetrain and ECU with the X3 M40i, so the stage structure and targets are identical. What differs is the individual car: Samuel calibrates each file against your exact vehicle, fuel and fitted hardware, so an X4 map is generated for that X4 rather than copied across from an X3.
From a standard 374 bhp and 500 Nm, the Stage 1 calibration targets 440 bhp and 680 Nm with no hardware and no mechanical work, just a hand-built file flashed through the OBD port. On the road the difference shows most between 2,000 and 5,000 rpm, which is where the G02 spends nearly all of its time.
Stage 2 requires a downpipe, and on OPF-equipped cars that means deleting the petrol particulate filter, which makes the car for off-road use in the UK. With that and an intake fitted, the calibration targets 480 bhp and 700 Nm from the factory turbo. If you would rather keep the OPF, Stage 1's 440 bhp needs no exhaust changes at all.
The ZF eight-speed fitted to the G02 is used across BMW's range behind considerably stronger engines and takes Stage 1 and Stage 2 torque in its stride. No transmission work is needed at these levels; it is only on hybrid and big-turbo builds that the gearbox becomes part of the specification conversation.
Order the stage, send your vehicle details, and the finished calibration appears in your bootmod3, MHD or MG Flasher account, typically inside 24 hours. You flash it yourself through the OBD socket in about fifteen minutes with no ramp and no appointment, and Samuel reviews datalogs afterwards to confirm the map is behaving exactly as intended on your car.
Keep exploring
Keep exploring X4 M40i tuning
Other B58 Gen 2 models we tune: M240i, M340i, M440i, Z4 M40i, X3 M40i, Supra 3.0.
Engine guide
B58 Gen 2 tuning
Every B58 Gen 2 BMW we calibrate, with the full Stage 1, 2 and 3 breakdown for the engine.
Learn moreStages
Stage 1 & Stage 2 explained
What separates Stage 1 from Stage 2 on the X4 M40i, the real-world gains and the hardware each one needs.
Learn morePricing
How tuning is priced
How the licence, off-the-shelf maps and custom calibration are priced. We quote your exact spec, never a fixed menu.
Learn moreGuide
What is bootmod3?
New to remote flashing? A plain-English explainer on the platform and how a custom map reaches your car.
Learn more