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
The BMW X4 M40i (G02, 2018–2025) runs the B58 Gen 2 and leaves the factory at 374 bhp · 500 Nm, xDrive, 8-speed ZF automatic. Samuel tunes the G02 SUV Coupe to the same standard — every map hand-calibrated for the specific car, its fuel grade and its installed hardware, not a base file loaded and left. X4 M40i Stage 1 alone takes it from 374 bhp · 500 Nm to 440 bhp · 680 Nm on the standard turbo, flashed over OBD on BM3, MHD or MG Flasher.
Add the Stage 2 hardware and the X4 M40i targets 480 bhp · 700 Nm; from there the B58 Gen 2 stretches to around 1000 bhp on a hybrid or big-turbo build with supporting fuelling. Whichever stage suits the X4 M40i, the file is delivered within 24 hours and is fully reversible to the supplied stock calibration.
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.
Read more →
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.
Read more →
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
X4 M40i Stage 1 lifts the B58 Gen 2 from a stock 374 bhp · 500 Nm to 440 bhp · 680 Nm, with no hardware required. The map is flashed through the OBD port on BM3, MHD or MG Flasher and is the starting point for almost every X4 M40i owner — broader torque and sharper throttle response from the factory hardware.
This page covers the G02 SUV Coupe (G02). They share the B58 Gen 2 engine and run the same core calibration, but every X4 M40i tune Samuel delivers is tailored to your exact car, fuel grade and installed hardware — never a base map loaded and left.
Stage 2 on the X4 M40i targets 480 bhp · 700 Nm and needs downpipe (OPF delete if 2018+) + intake. Everything else — turbo, fuel system, intercooler — holds within the Stage 2 figures on the B58 Gen 2.
On the right hardware spec the B58 Gen 2 in the X4 M40i reaches around 1000 bhp. Stage 1 and Stage 2 run the standard turbo; beyond that needs a hybrid or full big-turbo conversion with supporting fuelling, and the calibration is built bespoke per car.
Remotely. Once Samuel has your build details, the calibrated X4 M40i map is delivered to your flashing tool account (BM3, MHD or MG Flasher) within 24 hours and you flash it yourself over OBD in about 15 minutes. It's fully reversible — the original B58 Gen 2 stock file is supplied before you flash, so the car can return to factory at any time.
A factory warranty can be voided if BMW shows a tune caused a specific failure, so it's a personal call. Samuel's X4 M40i maps are calibrated to stay within the mechanical limits of the B58 Gen 2 hardware, and because the tune is reversible to stock before any dealer visit, many owners run a tuned X4 M40i without issue.
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