Tuning · BMW M240i (G42) (G42)
M240i
B58 Gen 2
The G42 generation M240i 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 G42 M240i (2022-present) is the second-generation 2 Series coupe, and the first to run the B58 Gen 2 in the smallest possible body. Stock is 374 bhp / 500 Nm, sent rear-wheel via the ZF 8HP. The G42 is structurally a smaller cousin of the M340i, same engine, same gearbox, same MG1CS003 ECU, wrapped in a tighter coupe shell. The result is the quickest stock G42 figures BMW have ever shipped in a 2 Series, and a platform that responds cleanly to a Stage 1 remap.
BMW M240i (G42) tuning
The BMW M240i (G42) (G42, 2021–present) runs the B58 Gen 2 and leaves the factory at 374 bhp · 500 Nm, xDrive, 8-speed ZF automatic. Samuel tunes the G42 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. M240i 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 M240i 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 M240i, the file is delivered within 24 hours and is fully reversible to the supplied stock calibration.
Configurator
Build your M240i 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 M240i G42 tuning, stages, hardware and what to expect from the B58 Gen 2
The G42 M240i runs the B58 Gen 2, the revised 3.0-litre single-turbocharged inline-six shared with the M340i, M440i, Z4 M40i and Toyota Supra 3.0. From the factory, BMW set the G42 M240i at 374 bhp / 500 Nm; the platform is the same Gen 2 hardware that responds cleanly to a remap. BMW M240i G42 tuning with Samuel is a substantial step up from the older F22 M240i because the underlying Gen 2 hardware is more capable from the start, with a more efficient intercooler and the TU fuel pump fitted from factory.
Stage 1
440 bhp · 680 Nm
No hardware required. The MG1CS003 DME is flashed via the OBD port. BMW M240i G42 Stage 1 unlocks 440 bhp and 680 Nm from the OEM hardware (up from 374 / 500 stock), with substantially more accessible torque and noticeably sharper throttle. The BMW M240i G42 chip tuning starting point, the most cost-effective change available on the platform.
Every G42 M240i tune Samuel produces is calibrated individually for the specific car, fuel grade and installed hardware, not a base map loaded and left. BMW M240i G42 tuning done correctly accounts for the chassis weight, 8HP gearbox 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.
Read more →
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.
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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.
M240i specs & stage targets
BMW M240i (G42) tuning at a glance
- Engine
- B58 Gen 2
- Body styles
- G42 Coupe
- Chassis codes
- G42
- Production
- 2021–present
- 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
M240i tuning — frequently asked questions
M240i 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 M240i owner — broader torque and sharper throttle response from the factory hardware.
This page covers the G42 Coupe (G42). They share the B58 Gen 2 engine and run the same core calibration, but every M240i 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 M240i 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 M240i 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 M240i 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 M240i 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 M240i without issue.
Keep exploring
Keep exploring M240i tuning
Other B58 Gen 2 models we tune: M340i, M440i, Z4 M40i, X3 M40i, X4 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 M240i, 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