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 G42 M240i squeezes the Gen 2 B58 into the smallest shell BMW currently offers it in, which is exactly why owners bring it to Samuel. A compact coupe carrying M340i running gear wants for nothing mechanically; what it responds to is calibration. With xDrive putting the power down and the ZF eight-speed handling shifts, the G42 turns software headroom into usable pace faster than any of its larger siblings.
From the factory the G42 M240i makes 374 bhp and 500 Nm. Samuel's Stage 1 calibration lifts that to 440 bhp and 680 Nm with no hardware changes at all, and the extra torque lands where the compact coupe uses it: third and fourth gear, real roads. Fit a downpipe and intake and Stage 2 pushes on to 480 bhp and 700 Nm, still on the standard turbo, still perfectly happy as a daily.
Beyond that, the platform keeps going. Hybrid and full-frame turbo conversions take a committed G42 build towards 1,000 bhp with the right fuelling behind them. Everything happens remotely: you flash through the OBD port using bootmod3, MHD or MG Flasher, Samuel writes the file to your account within 24 hours, and the original calibration stays saved so the car can go back to stock whenever you choose.
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.
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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.
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
It takes the G42 from 374 bhp and 500 Nm to 440 bhp and 680 Nm using nothing but software. The stock turbo, intercooler and fuel system all carry the Stage 1 figures comfortably, so there is no hardware bill; you flash the map yourself over OBD and the difference is obvious from the first drive.
Well, and it is one of the reasons the tuned G42 feels so quick. An extra 180 Nm from Stage 1 would trouble a rear-driven car in the wet; xDrive simply deploys it. Traction off the line and out of slow corners improves real-world pace far more than the headline power figure suggests, and no drivetrain changes are needed.
A downpipe, which on these OPF-equipped cars means an OPF delete, plus an upgraded intake. With those fitted, Samuel calibrates the standard turbo to 480 bhp and 700 Nm. Nothing else is required at this stage; the factory fuelling and cooling hold the figures on the Gen 2 B58.
The compact body doesn't limit the engine. A hybrid turbo with supporting fuelling moves a G42 into the 550 bhp-plus bracket, and a full-frame turbo conversion with port injection can carry the platform towards 1,000 bhp. Every build at that level is calibrated bespoke around the exact hardware list you send Samuel.
Because the map is written for your specific car either way. You supply your build details and fuel grade, Samuel calibrates the file by hand and delivers it to your bootmod3, MHD or MG Flasher account, and datalogs from your own driving let him refine it in the conditions the car actually lives in, not a one-off dyno session.
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